Leave Your Solar Panel Installation Work in Nishitama District, Tokyo to Kakeru Koumuten Co., Ltd.!
For Solar Panel and Battery Installation in
Nishitama District, Tokyo,
trust Kakeru Koumuten!
Kakeru Koumuten is a company specializing in exterior renovations.
As a company strong in roofing work, we are entrusted withsolar panel and battery installation considering roofing and waterproofing!
“How to Choose a Solar Panel Contractor in Nishitama District, Tokyo”
“Costs for Solar Panel and Battery Installation”
“Subsidies Available for Solar System Installation in Nishitama District, Tokyo”
We will also explain the above three points!
Installing solar panels can involve risks such as“the occurrence of leaks” and other troubles.
To ensure you have no regrets about your solar panel installation, we recommend obtainingestimates from about three companies!
Table of Contents (Tap to Open/Close)
- Reasons Why Kakeru Koumuten Is Chosen for Solar Panel Installation in Nishitama District, Tokyo
- Roof Inspection Before Installing Solar Panels
- Subsidies and Grants That May Be Applicable in Nishitama District, Tokyo
- Price List for Solar Panel and Storage Battery Installation
- Breakdown of Installation Capacity, Equipment, and Construction Costs
- Self-Estimate and Profit Simulation for Solar Power Generation
- Customer Testimonials
- Case Studies of Solar Panel Installations
- How to Choose a Solar Panel Installation Contractor in Nishitama District, Tokyo
- Benefits of Introducing Solar Equipment
- Points to Consider When Introducing Solar Power Generation
- How to Choose Solar Panels
- Frequently Asked Questions About Solar and Storage Battery Installation in Nishitama District, Tokyo
- If You’re Looking for a Solar Panel Installation Contractor in Nishitama District, Tokyo, Contact Kakeru Koumuten
- Characteristics of Nishitama District, Tokyo and Key Points for Solar Installation
- Service Areas in Nishitama District, Tokyo
Reasons Why Kakeru Koumuten Is Chosen for Solar Panel Installation in Nishitama District, Tokyo
Here are the reasons why our company is entrusted with solar panel installation by customers in Nishitama District, Tokyo.
“Our Unique Strengths in Solar Panel Installation That Cannot Be Imitated by Other Companies”
have received high praise from many customers.
Because we are confident, we welcome estimates from any number of companies!
1. We Also Handle Exterior Renovations Beyond Solar Panel Installation!
Problems such as leaks that occur with solar panel installation may be caused by insufficient checks on the roof and waterproofing at the installation site.
Even if one is knowledgeable about solar panels, there are cases where the roof and waterproofing at the installation site are outside their expertise, so caution is necessary.
It is reassuring to have expertise in roofing to avoid maintenance issues and troubles after installation!
Kakeru Koumuten Co., Ltd. is strong in roofing work and can also detach and attach solar panels in-house, allowing for quick responses to maintenance and urgent troubles after solar panel installation!
2.Facilities Specialized in Exterior Renovation
Kakeru Koumuten Co., Ltd. has organized the following warehouses and material storage areas to provide low-cost, high-quality solar work and exterior renovations.
We have established five bases for material storage and showrooms.
In-house Ownership of Scaffolding Materials
To ensure safety during work on the roof, we own the scaffolding materials necessary for temporary scaffolding according to the construction conditions and can assemble scaffolding in-house.
By not outsourcing scaffolding work and performing it with our own scaffolding team, we can also cut costs for scaffolding work.
We own scaffolding materials for approximately 50 single-family homes!
Even if there are height differences on the site, our in-house scaffolding team will plan the scaffolding according to the local conditions.
Storage of Materials in Our Large Warehouse
We store roofing materials and paints, and we can also store removed solar panels.
By ordering a large quantity of materials at once, you canpurchase materials at a lower cost!
Additionally, we always have a stock of roofing materials, allowing us torespond quickly in emergencies!
Sorting and Transporting Waste Materials In-House
The installation of solar panels often involves roofing work, generating various waste materials such as paints, wood, and metals.
By sorting and recycling waste materials, we can significantly cut waste disposal costs.
Exterior Renovation Dedicated Showroom
In the showroom, you can not only have meetings but also
check the actual foundation brackets for solar panels and see how they are installed on roofing materials!
We can also provide simulations of potential earnings and installation costs when introducing solar panels!
Since roofing and exterior wall work often accompany renovations, we also have samples of roofing materials and models that explain the structure, allowing for detailed explanations!
3.All Work Performed by Our Own Team
One of Kakeru Koumuten’s major strengths is its complete in-house construction.
By having a consistent system from inquiry to project completion, Kakeru Koumuten can provide high-quality roof renovations at reduced costs.
Additionally, one representative will handle everything from the estimate to the completion of the work.
Since the same person will be in charge, whether it’s sales or construction management, smooth communication is possible.
We can provide consistent in-house construction from temporary scaffolding installation, exterior wall painting, to roof renovations!
4. Various Permits and Skilled Workers
We have obtained construction industry permits and permits for industrial waste collection and transportation!
We also have nationally certified sheet metal and painting technicians on staff, and we are confident in our construction techniques.
We can also handle large-scale roof projects such as factories!
5. Warranty and Aftercare
In addition to the manufacturer’s warranty for solar panel installation, we also provide our own construction warranty (leakage warranty)!
(The construction warranty for solar panel installation is 10 years. Depending on the condition of the roof before installation, we may not be able to provide a warranty unless roof renovations are performed. The construction warranty is separate from the manufacturer’s product warranty, and the coverage and conditions vary depending on the warranty details.)
Aftercare is available every year, and we send out notification DM each year.
If you have questions about the warranty, please click on the image above!
6. Flexible and Prompt Response
Our company is equipped to handle various roofing troubles and situations.
If you cannot access the roof at high altitudes, we can respond using a drone!
During leak investigations, we can also conduct inspections using a thermal imaging camera.
If the power generation of solar panels decreases due to dirt, we can perform cleaning with a specialized brush.
We will respond according to your wishes.
7. Human Resource Development
To improve skills, we create various roof models and conduct practical training.
Since the construction methods vary depending on the shape and slope of the roof, we regularly provide technical training so that each staff member can handle various cases.
8. Creation of Easy-to-Understand Materials and Simulations
Kakeru Koumuten provides “estimates,” “layout diagrams,” and “power generation simulations,” as well as “solar construction guidebooks” and “profit and loss simulations” that take loan interest rates and electricity costs into account.
Profit and loss simulations can be created for projected cumulative profits and losses over 20 to 30 years.
Even customers who are not familiar with solar construction will receive materials that clearly summarize points to consider and disadvantages!
We encourage you to obtain comparative estimates and compare them with other companies’ plans!
Roof Inspection Before Installing Solar Panels
Once solar panels are installed, they will remain on the roof for 20 or 30 years.
Confirming “Is it okay to install them directly on the current roof?” before installation is the key point to prevent leaks and unnecessary expenses!
Kakeru Koumuten, which specializes in roofing work, has summarized the items you want to check before installation.
| 1. Types of Roofing Materials and Age | The fixing method varies depending on the roofing material, such as slate, tiles, metal roofs, and flat roofs (rooftop waterproofing). If the remaining lifespan of the roofing material is short, we may suggest a roof renovation first. |
| 2. Condition of Substrate and Waterproof Sheet | If the sheathing or roofing (waterproof sheet) under the roofing material is damaged, it will affect the fastening strength and waterproofing. We will also check for any signs of leaks. |
| 3. Orientation, Slope, and Shadows of the Roof | The orientation and slope of the roof surface, as well as shadows from neighboring houses, trees, and utility poles, will affect the power generation. We will create a layout diagram from the drawings and the site, and you can check the power generation simulation. |
| 4. Shape of the Roof and Usable Area | The number of panels that can be installed (installation capacity) is determined by the shape and size of the roof. The number of panels that can be installed varies depending on the size of the panels, so we will compare based on the total output of the roof. |
| 5. Fixing Method and Waterproofing Details | We will confirm whether the method involves drilling holes in the roofing material for fixing or using brackets to secure the roofing material. The fixing method varies by technique, so please check the waterproofing treatment method for the fixing parts during the estimate. |
| 6. Weight of the Roof | The roof will become heavier due to the panels being installed. After investigating the existing roof, substrate, and load-bearing capacity, switching to lighter roofing materials may also be an option if necessary. |
| 7. Installation Location of Equipment and Wiring | We will check the installation location of the power conditioner and storage battery, as well as the wiring route to the distribution board. The length of the wiring will also affect the cost. |
| 8. Ease of Scaffolding Setup and Delivery Routes | If there are elevation differences on the site, planning for scaffolding and the delivery routes for equipment and materials may require some ingenuity. The width of the front road and the elevation differences on the site will also be confirmed during the on-site survey. |
Fixing Methods and Verification Points by Roofing Material
| Roof Material | Main Fixing Method | Pre-Installation Check Points |
|---|---|---|
| Slate Roof | Varies by method (e.g., fixing brackets to the roof material and substrate with screws) | Waterproof treatment of fixing parts, cracks or deterioration of slate, condition of the substrate. If deterioration is advanced, consider roof overlay (cover method) or replacement first. |
| Tile Roof | Fixed with brackets and methods suited to the type of tile (even methods that do not drill holes in the tiles will secure to the substrate) | Type and condition of tiles, substrate, load-bearing capacity. Depending on the investigation results, it may be necessary to replace with lighter roofing material before installation. |
| Metal Roof (Horizontal/Vertical) | Fixed with catch-type brackets that grip the roof material (depends on the combination of roof material and brackets) | Whether the roof material and brackets are compatible, installation conditions from the roof material manufacturer. If compatible, methods that do not drill holes may be available. |
| Flat Roof / Rooftop | Fixed by installing a frame | Type and deterioration status of the waterproof layer, waterproofing around the frame. Consider in conjunction with the timing of waterproofing work. |
If you perform roof renovations 10 to 20 years after installation, additional costs for solar panel removal will apply. If the roof is deteriorating, it may be more cost-effective in the long run to renovate to high-durability roofing material before installation.
Kakeru Koumuten is strong in roofing work and can also handle solar panel removal in-house, so please consult us according to the condition of your roof!
▶ Click here for roof renovations in Nishitama District, Tokyo
PossibleSubsidies and Grants
If you are introducing solar panels or storage batteries in Nishitama District, Tokyo, there is a possibility that the systems from the “National Government,” “Tokyo,” and your local municipality may apply. In Nishitama District, there are municipal subsidies in Hinode Town, while Mizuho Town, Hinohara Village, and Okutama Town do not have their own solar or storage battery subsidies listed on their official pages.
The following is based on the content confirmed on the official pages of each system as of October 7, 2026. The acceptance status may change depending on the budget, so please check the latest information before contracting or starting work.
Eligibility Conditions and Application Timing for Subsidy Programs
| Program | Main Eligibility Conditions | Subsidy Amount | Application Period & Status |
|---|---|---|---|
| Tokyo “Household Solar Power Generation Promotion Project” | Individuals, corporations, or management associations installing unused solar power systems (output under 50kW, JET certification, etc.) in residential properties within Tokyo. The generated power must be used for residential purposes. Pre-application is required | Existing homes: 15,000 JPY per kW for up to 3.75 kW (maximum 450,000 JPY), 12,000 JPY per kW for over 3.75 kW to under 50 kW New homes: 12,000 JPY per kW for up to 3.6 kW (maximum 360,000 JPY), 10,000 JPY per kW for over 3.6 kW |
For the fiscal year 2026, pre-applications are being accepted from May 29 (will end once the budget is reached). From the pre-applications for fiscal year 2026, submission of a certificate issued by a financial institution will be mandatory at the time of performance reporting. |
| Tokyo “Household Storage Battery Promotion Project” | Owners of eligible devices (storage batteries registered with SII, excluding national and local governments). Must be installed between April 1, 2026, and March 30, 2027. If applying after October 1, 2026, only products registered with the national SII for fiscal year 2026 are eligible | Storage battery package: 100,000 JPY per kWh (maximum 1,200,000 JPY per household) Additional amount for participating in DR demonstration (100,000 JPY per unit; 150,000 JPY per unit if energy management equipment is installed) Expansion of storage battery unit: 60,000 JPY per kWh (maximum 720,000 JPY per household) |
For the fiscal year 2026, pre-applications are being accepted from May 29. Grant application and performance reporting will start from June 30. |
| Hinode Town “Subsidy for Installation Costs of Eco Housing Promotion Equipment” (Fiscal Year 2026) | Those who installed or renovated eco housing equipment such as solar power generation or storage batteries between April 1, 2025, and March 31, 2026, are eligible. A list of equipment is available with images on the town’s official page. Equipment previously subsidized under this program is not eligible. Application requires a copy of the grant decision notice from the Tokyo Environmental Public Corporation. | The town’s official page states “under consideration,” and it is expected to be published by late October. | From November 2, 2026 (Monday) to December 28, 2026 (Monday). Applications are made in the following fiscal year, and equipment installed by March 31, 2026, is eligible for fiscal year 2026. |
| National “DR Household Storage Battery Project” (Fiscal Year 2025 Supplement) | Newly introducing household storage systems that can be utilized for DR (demand response) with registered products. | Calculated based on an initial effective capacity of 34,500 JPY per kWh (subsidy rate within 3/10; maximum 600,000 JPY per application). | The budget was reached on May 29, 2026, and the public recruitment has ended (the official site states there are no plans to reopen public recruitment, and applications are currently not accepted). |
| National “Mirai Eco Housing 2026 Project” (Renovation) | Storage batteries are one of the eligible facilities, but they must be combined with essential works such as insulation renovations of windows (openings) and the structure; applications cannot be made for just the installation of storage batteries. Solar panels are not included as eligible facilities | Storage battery: 96,000 JPY per household | The program will end once the budget limit is reached. As of October 5, 2026, the application amount for renovations is displayed as 8% of the budget on the official website. Please check the reception status on the official website. |
The Tokyo solar power and storage battery subsidy program requires prior application. For storage batteries applied for after October 1, 2026, only products registered with the national SII will be eligible, and the requirements for equipment will also change. The subsidy for Hinode Town applies to equipment installed by March 31, 2026, and the application period is set from November 2, 2026, to December 28, 2026. The subsidy program in Mizuho Town ended at the end of March 2019. Eligibility conditions, application procedures, and the possibility of combining programs vary by system, and applying does not guarantee funding, so please confirm before contracting or starting work.
Kakeru Koumuten will provide guidance on eligibility conditions and application periods for each program after confirming them.
National Subsidy “DR Home Storage Battery Project (Support Project for Home Storage Systems for DR Resource Introduction)”
The national government has been implementing the “DR Home Storage Battery Project” to support the installation of home storage batteries.
This program targets those who are introducing new registered storage systems that can be utilized for demand response (DR). In the fiscal year 2026 supplementary budget, the subsidy amount is determined based on a standard amount of 34,500 JPY per initial effective capacity of 1 kWh, with a subsidy rate of up to 30% and a maximum of 600,000 JPY per application. There are conditions such as excluding items contracted or ordered before the grant decision.
However, the fiscal year 2026 supplementary budget reached its application amount on May 29, 2026, and the public recruitment has ended. The official website also states that there are no plans to reopen the public recruitment, and applications are currently not possible. Please check the official website for future public recruitment.
Furthermore, there are currently no subsidies confirmed for the installation of solar panels for existing homes.
👉 Click here for the official website of the DR Home Storage Battery Project
Tokyo “Promotion Project for the Introduction of Solar Power Generation in Homes”
This subsidy is for those who are installing unused solar power generation systems in residential homes within Tokyo. The simultaneous installation of storage batteries is not a condition.
● Existing homes: For systems under 3.75 kW, 150,000 JPY per kW (maximum 450,000 JPY); for systems over 3.75 kW and under 50 kW, 120,000 JPY per kW.
● New homes: For systems under 3.6 kW, 120,000 JPY per kW (maximum 360,000 JPY); for systems over 3.6 kW and under 50 kW, 100,000 JPY per kW.
● Additional amounts are available for the installation of rooftop frames and waterproofing work.
The target is for unused panels with an output of less than 50 kW that have obtained JET certification, installed in residential homes in Tokyo, and used in living areas. The process involves making a prior application and then applying for the grant after installation. Starting from the fiscal year 2026 prior application, it has become mandatory to submit a certificate issued by a financial institution during the performance report.
According to the official page of Tokyo, pre-registration is being accepted from May 29, Reiwa 8. It will end once the budget is reached, so please check the official page for the registration status.
👉 Here is the official page of Tokyo (Cool Net Tokyo)
Tokyo “Household Battery Installation Promotion Project”
This is a subsidy for the installation costs of battery systems aimed at increasing self-consumption of electricity generated by solar power and improving energy independence during emergencies.
●Battery package: 100,000 JPY per kWh (up to 1,200,000 JPY per household)
●Additional for participating in DR demonstration: 100,000 JPY per unit (150,000 JPY per unit if energy management equipment is installed)
●Expansion of battery units: 60,000 JPY per kWh (up to 720,000 JPY per household)
Eligible applicants are owners of the subsidized equipment (excluding national and local governments), and installation must occur between April 1, Reiwa 8 and March 30, Reiwa 11. If pre-registration is done after October 1, Reiwa 8, only products registered in the national SII for Reiwa 8 are eligible.
The official page of Tokyo states that pre-registration is being accepted from May 29, Reiwa 8. For detailed information, including conditions for combination with solar power generation, please check the official page.
👉 Here is the official page of Tokyo (Cool Net Tokyo)
Hinode Town “Subsidy for Installation Costs of Eco-Housing Promotion Equipment” (Reiwa 8)
Hinode Town is providing subsidies to residents who install eco-housing equipment such as solar power generation and battery systems, aiming to reduce and efficiently utilize the total energy consumption in the town, as stated on the town’s official page. Equipment that has previously utilized this subsidy program is not eligible. A list of eligible equipment is available with images on the town’s official page.
●Application period: From November 2, Reiwa 8 (Monday) to December 28, Reiwa 8 (Monday)
●Eligible installation period: Equipment installed or renovated between April 1, Reiwa 7 and March 31, Reiwa 8
●Main required documents: Application form, identification documents, copies of receipts, copies of contracts and itemized statements, before-and-after installation photos, product specifications, and copies of the Tokyo Environmental Public Corporation’s subsidy approval and confirmation notification, etc.
The subsidy amount is listed as “under consideration” on the town’s official page, and it is scheduled to be published by late October. Since the application is made in the following fiscal year after installation, please confirm with the town regarding the treatment if you plan to install after October 7, 2026 (Cooperation Promotion Division, Environmental Policy Section 042-588-5068).
👉 Here is the Hinode Town “Subsidy for Installation Costs of Eco-Housing Promotion Equipment (Reiwa 8)”
Additionally, Hinode Town has a “Living Environment Improvement Project” (covering repairs and renovations of houses, repainting of exteriors and roofs, etc., with a subsidy of 5% of the estimated or paid amount (excluding tax), limited to 100,000 JPY per household, from June 1, Reiwa 8 to February 26, Reiwa 9, on a first-come, first-served basis), but solar power generation and battery systems are not explicitly included as eligible.
👉 Here is the Hinode Town “Living Environment Improvement Project”
About Subsidy Programs in Mizuho Town, Hinokuni Village, and Okutama Town
Mizuho Town: The town’s official page “Subsidy Program for Purchase of Residential Renewable Energy and Energy-Saving Equipment” states that this program ended on March 31, 2019.
👉 Click here for Mizuho Town’s official page
Hinohara Village: The village’s official page “Subsidies for Introduction of Renewable Energy Equipment” does not list any unique subsidies for solar power generation or storage batteries, but provides information on national and Tokyo Metropolitan programs. As of April 1, 2026, the list of subsidy programs does not include solar power generation or storage batteries.
👉 Click here for Hinohara Village’s official page Click here for Hinohara Village’s subsidy program list
Okutama Town: The town’s official page on subsidy information (Migration and Settlement Support Subsidy, Settlement Promotion Support Fund, Vacant House Utilization Promotion Project Grant) does not include subsidies for residential solar power generation or storage batteries.
👉 Click here for Okutama Town’s subsidy information
Programs may change, so please check the latest information from each town and the national and Tokyo Metropolitan programs before signing a contract.
Solar Panel Installation & Storage Battery Installation Price List
⇧Service Menu | For Costs of Solar Panel Removal and Hot Water Heater Dismantling, Click Here
Breakdown of Installation Capacity, Equipment, and Construction Costs
The costs for solar panels and storage batteries should be confirmed by separating them into “Equipment Costs (Device Costs)” and “Construction Costs”.
Even for the same “Complete Solar Panel Installation,” the amount can vary significantly depending on the installation capacity, equipment grade, and roof condition.
Considerations for Installation Capacity (kW) and Storage Battery Capacity (kWh)
The installation capacity of solar panels is determined by “Output of One Panel (W) × Number of Panels”, with the unit being kW (kilowatt). Storage batteries are compared based on the amount of electricity they can store, represented in kWh (kilowatt-hour).
The amount of kW that can be placed on the roof varies for each house based on the shape, orientation, and size of the roof. At Kakeru Koumuten, we create layout diagrams from blueprints and on-site surveys to present the installation capacity.
On our pricing page, we list solar panel costs as approximately 800,000 JPY to 1,200,000 JPY for 3-5 kW, and 1,200,000 JPY to 1,900,000 JPY for 6-10 kW. (These are just approximate amounts and can vary based on wiring length, scaffold range, existing roofing materials, panel layout, etc.)
▶ Service Menu | For Costs of Solar Panel Installation and Storage Battery Installation, Click Here
Items to Confirm in the Estimate (Cost Verification)
When comparing estimates, it is common to compare different capacities and equipment by only looking at the amounts. Please check if the following items are clearly stated in each company’s estimate!
| 1. Solar Panels | Manufacturer, model number, output per panel (W), number of panels, total installation capacity (kW) should be listed. |
| 2. Power Conditioner | Manufacturer, model number, capacity, number of units, installation location (indoor/outdoor). Also check if it is a type that controls the battery together. |
| 3. Battery | Manufacturer, model number, capacity (kWh), range available during power outages (entire house or specific circuits), installation location. |
| 4. Mounting Frame and Hardware | Name of the hardware suitable for the roofing material and the method of securing it (whether it is a method that drills holes or a method that grips and secures). |
| 5. Wiring and Electrical Work | Wiring route and length, work around the distribution board, presence of a monitor to check power generation. |
| 6. Roof Reinforcement and Waterproofing | Details of waterproofing treatment at the fixing points, whether necessary roof repairs and substrate reinforcements are included. |
| 7. Application | How much support is included for applications to the power company, feed-in tariff (FIT) certification applications, and subsidy applications. |
| 8. Scaffolding | Scope and quantity of scaffolding. If it is simultaneous with roof work or exterior painting, confirm that the same scope and quantity are not counted twice. |
| 9. Removal and Disposal | Whether the removal of existing solar thermal water heaters or old panels and the disposal costs of waste materials are included. |
| 10. Tax Classification and Warranty | Whether it is tax-inclusive or tax-excluded, conditions under which additional costs may arise, details and duration of manufacturer warranty and workmanship warranty. |
If the capacity differs, both the amount and power generation will change. Kakeru Koumuten Co., Ltd. welcome competitive estimates, so if you bring estimates from other companies, we will explain the differences for each item!
Self-Estimate and Profit Simulation for Solar Power Generation
With the simulator above,
you can obtain an approximate estimate and a profit simulation for up to 30 years!
If you know the total installation capacity of solar panels on the roof and the capacity of the battery, you can perform an approximate estimate and profit simulation!
*The simulation results are approximate. Actual profits may vary based on assumptions such as electricity rates, self-consumption ratios, feed-in prices, and costs for equipment inspection or replacement.
Customer Voices
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customer reviews
Asao-ku, Kawasaki City | We received reviews about the ridge cap and rain gutter replacement work!
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customer reviews
Kohoku-ku, Yokohama | We received reviews about the roof overlay (cover method)!
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customer reviews
Kohoku-ku, Yokohama | We Received Reviews About Exterior Painting!
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customer reviews
Hodogaya-ku, Yokohama | We received reviews about our exterior fence construction!
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customer reviews
Tsurumi-ku, Yokohama | We received reviews about roof and exterior wall painting, as well as metalwork and rain gutter replacement work!
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customer reviews
Higashiyamato City, Tokyo | We received reviews about exterior painting and roof overlay (cover method)!
Case Studies of Solar Panel Installations
| Construction Details |
| Solar Panel Installation Battery Installation |
| Existing Roofing Material |
| Horizontal Metal Roof (Super Galtect) |
| Installation Capacity |
| Solar Panel: 4.3kW Battery: 5kWh |
| Base Mounting Hardware Used |
| Niigata Manufacturing/Aluminum Catch Type Hardware |
| Fixing Method & Waterproofing Details |
| Fixed using catch type hardware gripping the horizontal metal roof (Catch Method) |
| Price Range |
| 2,200,000 JPY～2,300,000 JPY *Due to the grant being provided, the actual burden amount is approximately 1,000,000 JPY Estimated recovery period for construction costs: about 8 to 9 years (self-consumption) *The grant amount and recovery estimates are based on the system and calculations at the time of construction, and may differ under the current system. |
| Construction Period |
| Approximately 3 days |
| Completion Month |
| April 2025 |
| Inquiry Details |
| I am considering the installation of solar panels and storage batteries. I heard that grants are available, and I would like to know how much will be provided. |
Our Proposal
We visited to provide an estimate and created a layout diagram for the solar panels from the drawings!
The layout diagram shows the arrangement of solar panels when placed on the roof.
Since we can also determine the installation capacity, it allows for power generation simulations and financial simulations.
We have also understood the expected amount of the grant, so we explained it to the customer along with the estimate!
How to Choose a Solar Panel Installation Contractor in Nishitama District, Tokyo
There are many solar panel installation companies that serve Nishitama District, Tokyo, and you may be unsure which company to choose.
Therefore, when requesting solar panel installation and battery storage installation work, let’s check the following four points.
● Have extensive knowledge not only about solar panels but also about roofs
● Confirm the existence of warranties and aftercare services
● Obtain estimates from multiple companies (three companies are a guideline)
● Check if they provide support for subsidy applications
By confirming the above four points, you will be able to choose a reliable company.
Have knowledge about roofs as well as solar panels
Defective installation of solar panels can sometimes be caused by a lack of knowledge and verification regarding roofs and waterproofing.
While knowledge about solar panels is certainly important, understanding the roof and waterproofing at the installation site of the solar panels is also crucial.
⚠︎Examples of troubles caused by insufficient checks on roofs and waterproofing
・Solar panels were installed on a severely deteriorated roof, leading to leaks
・Solar panels were installed on a roof with a short lifespan, necessitating renovations to detach and reattach the solar panels within a few years
・Misjudging the type of waterproofing led to incorrect treatment and subsequent leaks
and more
When installing solar panels, understanding the condition and type of the existing roof allows for installation that avoids unnecessary expenses and unexpected troubles.
▶ Go to “Roof Check Before Installing Solar Panels” in this article
Confirm the existence of warranties and aftercare services
When choosing a solar installation company, make sure to check for warranties. It is important to confirm not only the duration of the warranty but also the scope of coverage, exclusions, and cost conditions.
Solar panels and battery storage units come with manufacturer warranties, but also check for the existence of installation warranties in case leaks occur after installation!
For companies that offer installation warranties, if leaks occur after installation, they may cover the repairs under the warranty, provided it is within the warranty period and conditions.
Additionally, some companies offer aftercare services separate from warranties, so be sure to check if the company you are considering has aftercare services.
Since abnormalities or damages on the roof can be in hidden areas, customers may not notice them themselves.
By conducting inspections of hidden areas during aftercare maintenance, you can more easily detect abnormalities early and prevent major repairs or failures!
At Kakeru Koumuten Co., Ltd., the installation of solar panels comes with a leak warranty as part of the workmanship warranty. (The warranty for solar panel installation is 10 years, and depending on the condition of the roof before installation, we may not be able to provide a warranty unless roof renovation is performed.)
We also conduct aftercare maintenance and send out annual DM!
After checking the DM, if you wish, we will visit for aftercare maintenance!
Obtain estimates from multiple contractors (3 companies as a guideline)
When requesting solar panel installation, let’s obtain estimates from multiple contractors.
Even for the same manufacturer and the same construction content, costs may vary, and warranties and after-sales services may differ.
Additionally, obtaining multiple estimates makes it easier to negotiate prices.
To request from your preferred contractor at a lower price, we recommend obtaining estimates from multiple contractors.
When comparing estimates,
“Check the estimate items”
“Type of solar panels”
“Warranties and after-sales services”
let’s compare them in detail and make a judgment! If the rank of auxiliary materials is low or if steps are skipped, costs can be reduced, so avoid making judgments based solely on price!
▶ Go to “Breakdown of installation capacity, equipment, and construction costs” in this article
Check if they provide support for subsidy applications
There may be subsidies available for solar panel installation and battery installation, but if the order of procedures is incorrect or if there are deficiencies in the documents, it may not be granted.
Since there are systems that require prior application, such as the Tokyo subsidy, it is reassuring to have a contractor that supports the preparation of necessary documents and the flow of procedures.
Complete the procedures specified for each system (for the Tokyo subsidy, prior application) before proceeding with the construction!
For the Tokyo subsidy, after installation, you will need to submit a grant application and performance report, which will be granted after review! (The flow of procedures varies by system)
▶ Go to “Subsidies and grants that may be applicable in Nishitama District, Tokyo” in this article
Benefits of Introducing Solar Equipment
The benefits of introducing solar panels are the following 5 points!
Benefit 1: Economic Benefits
The biggest advantage of introducing solar panels is the economic benefit!
The selling price for electricity has decreased compared to ten years ago, but by consuming the electricity generated, you can reduce the amount of electricity purchased from the utility company and gain benefits!
As electricity prices rise, the ability to cover your consumption with solar power becomes attractive!
If you plan to use the generated electricity at night, installing a storage battery is essential!
Furthermore, the selling price (FIT) for residential use (under 10kW) will be set as “24 yen/kWh for the first four years, and 8.3 yen/kWh from the fifth to the tenth year” for certifications after October 2025, with the same price applying for the 2026 fiscal year. After the fifth year, it is likely to be more advantageous to use it at home (self-consume) rather than selling it, making the combination with a storage battery a viable option.
👉 Ministry of the Environment | For purchase prices and periods, click here
Advantage 2 Subsidies can be utilized!
The conditions and amounts of subsidies vary by prefecture and municipality, but if you meet the requirements, you may be able to utilize subsidies!
Reducing the actual burden through subsidies is a significant advantage!
In Nishitama District, there may be national and Tokyo Metropolitan programs available, and Hinode Town also offers local subsidies. The Hinode Town subsidy has an application period from November 2 to December 28 of Reiwa 8, and applications are made in the following fiscal year after installation (please check the official page for details).
Advantage 3 Environmentally friendly!
Solar power generation emits low levels of carbon dioxide and reduces dependence on fossil fuels, contributing to the mitigation of global warming.
Since solar panels do not produce noise or exhaust gases during the generation process, they are considered an environmentally friendly method of power generation. (However, devices like power conditioners do have operational noise.)
Advantage 4 Heat insulation effects are expected!!
By installing them on the roof or rooftop, the panels block direct sunlight from hitting the roof.
Especially in summer, it can help reduce the temperature of the roof, providing expected heat insulation effects!
（This does not improve the insulation performance of the building itself）
Benefit 5 Electricity can be used even during power outages!!
If a storage battery is installed, it is possible to use electricity even during emergencies such as power outages!
Even without a storage battery, if you have a power conditioner with autonomous operation functionality, you may be able to use electricity from a dedicated outlet during daytime generation.
（The devices, output, and duration that can be used during a power outage vary depending on the model and wiring method）
What points should be noted when introducing solar power generation?
Next, we will explain the “three points to note” when installing solar panels!
Point 1 Maintenance costs can be incurred
A particularly overlooked maintenance cost is for the roof where solar panels are installed.
If you perform roof renovations 10 to 20 years later, there will be costs for removing and reattaching the solar panels.
If the existing roof is deteriorating, it is reassuring to renovate it with durable roofing materials before installing solar panels!
Additionally, there will be costs for regular inspections of the equipment, repairs or replacements of the power conditioner, and updates due to the deterioration of the storage battery.
It would be reassuring to consider maintenance costs in simulations before introducing solar panels!
Point 2 The risk of leaks increases depending on the roofing material
The fixing methods for slate roofs and tile roofs vary by construction method, but when fixing hardware with screws to the roofing material or substrate, waterproofing of the fixed areas becomes crucial.
In methods that involve making holes in the roof, the risk of leaks inevitably arises.
Of course, we will perform thorough waterproofing, but if you are concerned about making holes, replacing the roofing material with a metal roof and fixing the solar panels using the catch method is also an option. (The catch method has compatibility conditions between the roofing material and hardware, and it cannot be used with all metal roofs)
Catch-type base metal fittings for horizontal metal roofs
Note 3: The roof will become heavier
Since solar panels will be installed, the roof will become heavier. After investigating the existing roof, substrate, and load capacity, switching to a lighter roof may also be an option if necessary.
How to Choose Solar Panels?
There are many manufacturers of solar panels, and their output and costs vary.
It is not simply a matter of “this manufacturer has the best solar panels”; it is important to choose solar panels that are suitable for your life plan and building!
Here are some points to consider when comparing solar panels!
Choosing Method 1: Compare by Total Output of the Roof
When installing solar panels on the roof, it is important to know how much power can be generated in a limited area, and the more power generated, the better!
Solar panels vary in size and output depending on the manufacturer.
A panel with an output of 350W and a panel with an output of 400W may seem like the higher output panel is better at first glance.
However, if the size of the panel does not fit well on the roof, “20 panels of 350W can be installed, while only 15 panels of 400W can be installed,” meaning the number of panels that can be installed on the same roof may differ due to the size of the panels.
400W×15 panels = 6kW (total output of the roof)
350W×20 panels = 7kW (total output of the roof)
As shown above, even if the output of a single panel is lower, the total output of the roof may be higher!
It is important to consider the total output of the roof rather than the output of a single panel!
*The above is a calculation of total output (kW). The actual power generation (kWh) will vary depending on conditions such as the roof’s orientation, slope, and shading.
Choosing Method 2: Compare by Degradation Rate of Solar Panels
Solar panels have a degradation rate, and their output gradually decreases over 10 years and 20 years.
The degree of output reduction after long-term use varies by product. The manufacturer’s output guarantee value is a standard figure for warranty purposes and does not indicate the actual degradation rate or power generation itself.
Choosing solar panels without considering the degradation rate, in addition to the initial output, will lead to a more satisfactory decision!
Choosing Method 3: Compare by Warranty Period
There are several types of warranties for solar panels, including “output warranty,” “natural disaster warranty,” and “system warranty,” and the warranty periods vary by manufacturer.
Regarding the output warranty, some manufacturers offer a 30-year warranty while others provide a 10-year warranty, so it varies widely!
It’s always better to have a longer warranty, so let’s check the warranty periods and conditions of the manufacturers you are considering!
Frequently Asked Questions about Solar Panel and Battery Installation in Nishitama District, Tokyo
We have compiled frequently asked questions from customers considering the installation of solar panels and batteries in Nishitama District, Tokyo. (Tap to open the answers)
How much does it cost to install solar panels and batteries in Nishitama District, Tokyo?
The cost varies depending on the installation capacity, equipment, and roof condition. In the above construction example (solar panel 4.3kW + battery, completed in April 2025), it was 2.2 million yen to 2.3 million yen.
For cost estimates by capacity, please refer to the solar panel and battery installation pricing page. We will create a layout diagram from the drawings and site survey and provide a free estimate!
Are there any subsidies available for solar panel and battery installation in Nishitama District, Tokyo?
As of October 7, 2026, Tokyo’s “Household Solar Power Generation Promotion Project” (for existing homes, 15,000 yen per kW for systems under 3.75kW, with a maximum of 450,000 yen) and “Household Battery Installation Promotion Project” (100,000 yen per kWh, with a maximum of 1.2 million yen per household) are accepting pre-applications starting May 29, 2026, as stated on the official Tokyo (Cool Net Tokyo) page. In Hinode Town, there is a subsidy for the installation costs of eco-friendly housing promotion equipment (the application period for fiscal year 2026 is from November 2 to December 28, and equipment installed by March 31, 2026, is eligible), as noted on the official page of Hinode Town. The subsidy for residential renewable energy and energy-saving equipment in Mizuho Town ended in March 2019, and there are no specific subsidies for solar panels and batteries listed on the official pages of Hinokubo Village and Okutama Town. The national DR household battery project has closed its public recruitment.
Since the application status may change, please refer to the subsidy and grant section and consult with us before signing a contract.
Can I apply for subsidies after the construction is completed?
This varies by program. Tokyo’s subsidies require pre-application, while the subsidy in Hinode Town is applied for in the following fiscal year (for fiscal year 2026, equipment installed by March 31, 2026, is eligible). Conditions such as whether you can contract and start construction before applying may differ by program, so please confirm before signing a contract.
The order of procedures varies by program, so please check before signing a contract and starting construction.
Can solar panels be installed on slate roofs? I’m worried about leaks.
Installation is possible on slate roofs, but it is necessary to check the condition of the roofing material and substrate. The method of securing the panels varies by construction method, and when using a method that secures brackets to the roofing material or substrate, waterproofing treatment of the fixed parts is essential.
Kakeru Koumuten Co., Ltd. is a specialized exterior renovation company strong in roofing work, so we will check the condition of the roof before installation and suggest methods such as roof overlay (cover method) or replacement if deterioration is progressing.
My roof is old. Should I do a roof renovation first?
It depends on the condition of the roof. If a roof renovation is needed after 10 to 20 years of installation, there will be additional costs for removing and reinstalling solar panels. If the remaining lifespan of the roof is short, it may be more cost-effective to renovate with durable roofing materials before installation.
Please consult us about the installation process after confirming the condition of the roof through an on-site survey!
Should I install a storage battery together with the solar panels?
If you want to use the generated electricity at night or prepare for power outages, simultaneous installation is recommended. The selling price of electricity will be 8.3 yen/kWh after the fifth year, making it more advantageous to use it at home rather than selling it.
Additionally, the subsidy for storage batteries in Tokyo (for Reiwa 8, 100,000 yen per kWh, with a maximum of 1,200,000 yen per household) is a program aimed at increasing self-consumption of electricity generated by solar power. You can compare “solar only” and “solar + storage battery” through a financial simulation.
How many kW can be installed on my roof? Is it okay for north-facing or shaded roofs?
The capacity that can be installed varies depending on the shape, orientation, and size of the roof. At Kakeru Koumuten, we create a layout diagram from the drawings and on-site survey, and provide you with the installation capacity and power generation simulation.
The Nishitama District consists of four towns and villages with different terrains, from Mizuho Town to Hinohara Village and Okutama Town, where over 90% of the area is forested. The shape and orientation of the roof, as well as the shading from surrounding buildings, will differ for each house. You can check the expected power generation through the power generation simulation.
How long will the construction period be?
For the above construction example (solar panel 4.3 kW + storage battery), it took about 3 days. The duration may vary if roofing work is done simultaneously or depending on the shape of the roof and installation capacity.
Please note that additional time is required for subsidies and applications to the power company, so please consult us as soon as possible.
What is the current selling price (FIT)?
For residential use (less than 10 kW), the selling price from certifications after October 2025 will be 24 yen/kWh for the first four years, and 8.3 yen/kWh from the fifth to the tenth year, with the same price applied in the 2026 fiscal year.
The idea is to recover initial costs quickly during the first four years and focus on self-consumption afterward. Kakeru Koumuten provides a financial simulation that considers loan interest rates and electricity costs.
Can you handle maintenance and inspections after installation?
Yes, we can. Kakeru Koumuten sends out annual after-service maintenance DM notices and visits for inspections upon request. We can also clean solar panels with a special brush if the power generation decreases due to dirt.
Since it is difficult to check areas on the roof by yourself, please feel free to consult us if you have any concerns.
Can you also renovate a roof that already has solar panels installed?
It is possible. Kakeru Koumuten Co., Ltd. can detach and reattach solar panels in-house, allowing us to perform roof overlay (cover method) or re-roofing after removing the panels, and we will handle everything consistently until reinstallation. The removed panels can be stored in our own warehouse.
For costs, please refer to the solar panel detachment and water heater removal pricing page.
If you are looking for a solar panel installation contractor in Nishitama District, Tokyo, please consult Kakeru Koumuten
Our company handles many exterior renovations, including solar panels, roof work, and exterior wall work in Nishitama District, Tokyo.
We receive requests from many customers, including renovation companies and real estate agencies!
Kakeru Koumuten promises “high-quality renovations at low cost”, and we have received great feedback from numerous customers.
We continue to update our construction performance every year, and we will strive to improve quality to satisfy even more customers in the future.
Our company can perform not only roof overlay (cover method) and re-roofing but also partial roof repairs, exterior painting, and exterior wall cover methods all in-house.
We are happy to assist with small jobs like partial repairs and rain gutter cleaning!
In urgent cases like leak repairs, we may be able to provide temporary measures without setting up scaffolding, as long as safety can be ensured, so please consult us!
“I want to know recommended solar panels”, “I want to keep costs down as much as possible”, “I just want an estimate for now”, we will provide the best solutions for your specific requests.
We will never propose unnecessary work that prioritizes profit!
We always stand in our customers’ shoes and will propose the best construction plan!
We are confident that we will not lose in terms of cost, quality, and planning compared to other companies for exterior work!
We are confident, so we welcome competitive quotes!
Estimates are completely free, and if we are inferior to other companies, you are free to decline!
Characteristics of Nishitama District, Tokyo and Points for Solar Work
Nishitama District consists of four towns and villages: Mizuho Town, Hinode Town, Hinohara Village, and Okutama Town, located in the western part of Tokyo. Even within the same district, the terrain and surrounding environment vary greatly by town and village, and the points to be careful about when installing solar panels and storage batteries also change. Below are the characteristics of each town and village in Nishitama District, Tokyo, and points to be careful about during installation (tap to open).
View the characteristics of Nishitama District, Tokyo and points for solar work
■ Mizuho Town: The Sayama Hills spread to the east, and tea fields extend to the north. The hazard map was revised in June of Reiwa 8
Mizuho Town has an area of 16.85 square kilometers, approximately 5.76 kilometers east to west and 6.115 kilometers north to south, with the Sayama Hills located in the eastern part of the town and tea fields spreading to the north of the town center, as stated on the town’s official page. In residential areas close to the green hills, the shadows cast by surrounding trees vary from house to house. The town’s disaster prevention hazard map was revised in June of Reiwa 8, and in addition to the flood and landslide maps, new maps for internal water and landslide disasters were created, as noted. Since the placement of power conditioners and storage batteries can affect their impact during flooding depending on where they are installed indoors or outdoors, please confirm the assumptions about your residence’s location and consult us about the installation site.
■ Hinode Town: A long, narrow town from east to west. Check site conditions and delivery routes on-site for each district
Hinode Town has an administrative area of 28.07 square kilometers, with a length of approximately 12.0 kilometers east to west and 2.5 kilometers north to south, forming a long and narrow shape, as stated on the town’s official page. Within the town, the elevation differences of the sites and the width of the front roads may vary by district, so it is necessary to confirm the scaffolding setup and the delivery routes for panels and storage batteries on-site. At Kakeru Koumuten, our in-house scaffolding team plans the scaffolding according to the site conditions, creates layout diagrams from the drawings and site surveys, and you can confirm this through power generation simulations.
■ Hinohara Village: 93% of the area is forested land. Settlements are scattered along the river, and confirm the areas at risk of landslides
Hinohara Village has a total area of 105.41 square kilometers, with 93% being forested land, surrounded by steep mountains, and settlements are scattered along the Akigawa River from north to south, as stated on the village’s official page. The shadows cast by the surrounding mountains and trees vary by location, and in narrow areas, it may be necessary to devise delivery routes for materials. The village’s landslide and flood hazard maps are published by district, showing landslide warning areas and special warning areas. Please confirm the area of your residence and consult us about the installation site.
■ Okutama Town: 94% of the town is forested. Consideration for winter cold and landslide warning areas
Okutama Town has an area of 225.53 square kilometers, measuring 19.5 kilometers east to west and 17.5 kilometers north to south, and the town’s basic environmental plan states that 94% of the town’s area is covered by forests, with annual precipitation at the Okutama Observatory ranging from approximately 1,300 to 2,100 millimeters, and the average temperature is around 12 to 13℃, with January’s average temperature at 1.5℃ (these values are from the observatory, not the entire town). Due to the location surrounded by mountains, the sunlight impact varies by location because of the surrounding mountains and trees, so please check with a power generation simulation. For storage batteries, confirm the installation conditions (such as the usable temperature range) with the manufacturer’s specifications and consult us about the installation location. Additionally, the Tokyo Metropolitan Government designated landslide warning areas on June 28, 2019, and maps have been created and distributed for each community, as stated on the town’s official page.
■ Roof types and ages vary from house to house. Check the roof and waterproofing before installation
Even within the same town, roof types, ages, and lot shapes differ from house to house. The capacity and fixing methods that can be installed vary depending on the shape and orientation of the roof and the materials used. At Kakeru Koumuten, we will check the type and condition of the roof and the situation of the lot before installation, and propose fixing methods, waterproofing details, and scaffolding plans.
■ The annual sunshine hours at the Tokyo Observatory are approximately 1,927 hours
According to the Japan Meteorological Agency’s average values (1991-2020), the annual sunshine hours at the Tokyo Observatory are about 1,927 hours, with January (approximately 193 hours) having the most and June during the rainy season (approximately 124 hours) having the least. (This is a reference value, not based on measurements within Nishitama District.)
The power generation in Nishitama District can also vary due to the shadows cast by surrounding buildings, mountains, and trees, so it is important to conduct a year-round power generation simulation and choose the capacity of the storage battery to match the times of high electricity usage.
Our company handles many exterior construction and solar power projects in Nishitama District, Tokyo.
We are happy to assist with partial roof repairs such as roof overlay work, roof replacement, and leak repairs, as well as other repairs! Please feel free to consult us about any sudden troubles!
Service Area in Nishitama District, Tokyo
Kakeru Koumuten accepts requests throughout Kanagawa Prefecture and all of Tokyo.
List of Areas in Nishitama District, Tokyo
● Mizuho Town
Mizuho Town Ishihata / Mizuho Town Komagatake Fuji / Mizuho Town Takane / Mizuho Town Tonogaya / Mizuho Town Nagaoka Shimokoshioka / Mizuho Town Nagaoka Nagasebe / Mizuho Town Nagaoka Fujihashi / Mizuho Town Nagaoka / Mizuho Town Nihongi / Mizuho Town Hakonegasaki / Mizuho Town Hakonegasaki Nishimatsubara / Mizuho Town Hakonegasaki Higashimatsubara / Mizuho Town Fujiyama Kurihara Shinden / Mizuho Town Minamihei / Mizuho Town Musashi / Mizuho Town Musashino
● Hinode Town
Hinode Town Okuno / Hinode Town Hirai
● Hinohara Village
Hinohara Village Ozawa / Hinohara Village Kazuma / Hinohara Village Kobe / Hinohara Village Kamimoto / Hinohara Village Kurakake / Hinohara Village Shimomoto / Hinohara Village Nangō / Hinohara Village Hiri / Hinohara Village Fujiwara / Hinohara Village Hitosato / Hinohara Village Mito / Hinohara Village Honjuku
● Okutama Town
Okutama Town Umizawa / Okutama Town Umezawa / Okutama Town Ootanba / Okutama Town Kawai / Okutama Town Kawano / Okutama Town Kawachi / Okutama Town Kodanba / Okutama Town Sakae / Okutama Town Shirawara / Okutama Town Tanazawa / Okutama Town Dansaburo / Okutama Town Tōrō / Okutama Town Hibara / Okutama Town Hara / Okutama Town Hikawa
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・Trust Kakeru Koumuten for exterior renovations in Nishitama District, Tokyo!
・Kakeru Koumuten Co., Ltd. project achievements
・Kakeru Koumuten Co., Ltd. aftercare services
・Kakeru Koumuten Co., Ltd. service menu and price list
・Kakeru Koumuten Co., Ltd. staff blog and announcements
・Explaining the importance of comparative estimates and key points!
・Top 12 solar power generation manufacturers! Features and selection tips included!
・What are the installation costs for solar power generation? Thorough explanation of cost-saving tips!
・What are the best locations for installing solar power generation? Key points for site selection included!
・Find out more about solar power generation estimates here!
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contact Kakeru Koumuten Co., Ltd.
Kakeru Koumuten is a young company whose team is, on average, in their late twenties, but our skills are second to none.
Our greatest strength is that we handle scaffolding, roofing and painting entirely in-house. In an industry where these tasks are usually divided among contractors, our complete service simplifies project management and helps keep costs down. Above all, if a problem arises, we respond promptly.
We proudly describe ourselves as the youngest and most helpful renovation company in Kanagawa!
