Leave Your Solar Panel Installation Work in Chuo City, Tokyo to Kakeru Koumuten Co., Ltd.!
For solar panel and storage battery installation in
Chuo Ward, Tokyo,
Kakeru Koumuten is at your service!
Kakeru Koumuten is a company specializing in exterior renovations.
As a company strong in roofing work, we are entrusted with solar panel and storage battery installations considering roofing and waterproofing!
“How to Choose a Solar Panel Contractor in Chuo Ward, Tokyo”
“About the Costs of Solar Panel and Storage Battery Installation”
“About Subsidies Applicable to Solar System Installation in Chuo Ward, Tokyo”
We will also explain the above three points!
The installation of solar panels carries risks such as “the occurrence of leaks” and other troubles.
To ensure a satisfactory solar panel installation, we recommend obtaining about three estimates!
Table of Contents (Tap to Open/Close)
- Reasons Why Kakeru Koumuten is Chosen for Solar Panel Installation in Chuo City, Tokyo
- Roof Inspection Before Installing Solar Panels
- Possible Subsidies and Grants Available in Chuo City, Tokyo
- Price List for Solar Panel and 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 Chuo City, 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 Battery Installation in Chuo City, Tokyo
- If You Are Looking for a Solar Panel Installation Contractor in Chuo City, Tokyo, Contact Kakeru Koumuten
- Characteristics of Chuo City, Tokyo and Points for Solar Installation
- Service Area in Chuo City, Tokyo
Reasons Why Kakeru Koumuten is Chosen for Solar Panel Installation in Chuo City, Tokyo
Regarding the reasons our company is entrusted with solar panel installation by customers in Chuo City, Tokyo,
“Our Unique Strengths in Solar Panel Installation That Cannot Be Imitated by Other Companies”
have received high praise from many customers.
so we would appreciate it if you could compare our estimates with those of other companies.
Because we are confident, we welcome estimates from any number of companies!
1. We Also Handle Exterior Renovations Aside from Solar Panel Installation!
Issues such as leaks that occur during solar panel installation may be caused by insufficient checks on the roof and waterproofing at the installation site.
Even if you are knowledgeable about solar panels, there are cases where the roof and waterproofing at the installation site are outside your 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 prepared 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 construction conditions and can assemble scaffolding in-house.
By not outsourcing scaffolding work and using our own scaffolding team, we can also reduce the costs of 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 In-house 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 can purchase materials at a lower cost!
Additionally, we always have a stock of roofing materials, so we can respond 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 paint, wood, and metal.
By sorting and recycling waste materials, we can significantly cut waste disposal costs.
Exterior renovation dedicated showroom
In the showroom, not only can you have meetings, but you can also
check the actual foundation brackets for solar panels and see how they are installed on roofing materials!
You can also simulate the revenue and installation costs when introducing solar panels!
Since roofing and exterior wall work often accompany each other, we also provide samples of roofing materials and models that show 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 maintaining 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 project completion.
Since the same person will manage sales and construction oversight, smooth communication is ensured.
We can provide consistent in-house construction from temporary scaffolding setup to exterior wall painting and roof renovations!
4. Various Permits and Skilled Workers
We have obtained construction industry licenses and permits for industrial waste collection and transportation!
We also have nationally certified sheet metal and painting technicians, giving us confidence in our construction techniques.
We are capable of handling large-scale roofing projects for factories and other facilities!
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 a roof renovation is performed. The construction warranty is separate from the manufacturer’s product warranty, and the coverage and conditions vary based on the warranty details.)
Aftercare is available annually, 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.
Even if you cannot access the roof at high places, we can utilize drones to assist!
During leak investigations, we can also conduct surveys using a thermal imaging camera.
If the power generation of your solar panels decreases due to dirt or other factors, we can provide cleaning services using specialized brushes.
We will respond according to your preferences.
7. Human Resource Development
To enhance skills, we create various roofing 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 not only “estimates,” “layout diagrams,” and “power generation simulations” but also a “solar installation guidebook” and a “profit and loss simulation” that takes into account loan interest rates and electricity costs.
The profit and loss simulation can be created for projected cumulative profits and losses over 20 to 30 years.
Even customers who are not familiar with solar installations will receive materials that clearly summarize important points 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 to 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, specializing in roofing work, has summarized the items to check before installation.
| 1. Types of Roofing Materials and Age | The fixing method varies depending on the roofing materials such as slate, tiles, metal roofs, and flat roofs (roof waterproofing). If the remaining lifespan of the roofing material is short, we may suggest a roof renovation first. |
| 2. Condition of the Substrate and Waterproof Sheet | If the sheathing or roofing (waterproof sheet) under the roofing material is damaged, it can 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, can affect the amount of electricity generated. We will create a layout diagram from the drawings and the site, and you can check it with a power generation simulation. |
| 4. Shape of the Roof and Usable Area | The number of panels (installation capacity) that can be placed depends on the shape and size of the roof. Since the number of panels that can be installed varies depending on the size of the panels, 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 fastening or using brackets to secure the roofing material. The fixing method varies by technique, so please check the waterproofing treatment method for the fixed parts during the estimate. |
| 6. Weight of the Roof | The roof will become heavier due to the panels. After investigating the existing roof, substrate, and load-bearing capacity, switching to lighter roofing materials may 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 also affects the cost. |
| 8. Ease of Scaffolding Setup and Delivery Routes | If there is a height difference 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 checked during the site survey. |
Fixing Methods and Checkpoints 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 suitable for the type of tile (even methods that do not drill holes in the tiles will fix to the substrate) | Type and condition of tiles, substrate, load-bearing capacity. Depending on the investigation results, there may be a method to replace with lightweight roofing material before installation. |
| Metal Roof (Horizontal and 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, a method that does not drill holes may be selectable. |
| 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, there will be additional costs for the removal and reinstallation of solar panels. If the roof is deteriorating, renovating to a highly durable roofing material before installation may help reduce costs in the long run.
Kakeru Koumuten Co., Ltd. specializes in roofing work and can also handle the removal and reinstallation of solar panels in-house, so please consult us according to the condition of your roof!
▶ Click here for roof renovations in Chuo City, Tokyo
PotentialSubsidies and Grants in Chuo City, Tokyo
If you are introducing solar panels or storage batteries in Chuo City, Tokyo, there is a possibility that the systems from the “National Government,” “Tokyo Metropolitan Government,” and your residence’s “Chuo City” may apply.
The following information is based on the official pages of each system as of October 7, 2026. The application status may change depending on the budget, so please check the latest information before contracting or starting work.
Eligibility Conditions and Application Period for Subsidy Programs
| Program | Main Eligibility Conditions | Subsidy Amount | Application Period & Status |
|---|---|---|---|
| Tokyo “Home Solar Power Generation Promotion Project” | Individuals, corporations, or management associations installing a new unused solar power system (output less than 50kW, JET certification, etc.) in residential properties within Tokyo. The generated power must be used in the residential part. Pre-application is required. | Existing homes: 15,000 JPY per kW for systems up to 3.75kW (maximum 450,000 JPY), 12,000 JPY per kW for systems over 3.75kW and under 50kW. New homes: 12,000 JPY per kW for systems up to 3.6kW (maximum 360,000 JPY), 10,000 JPY per kW for systems over 3.6kW. |
For the fiscal year 2026, pre-applications are being accepted from May 29 (will end once the budget is reached). From the pre-application for the fiscal year 2026, submission of a certificate issued by a financial institution will be mandatory at the time of performance reporting. |
| Tokyo “Home Battery Installation Promotion Project” | Owners of eligible equipment (batteries registered with SII, excluding national and local governments). Installation must occur between April 1, 2026, and March 30, 2031. If applying after October 1, 2026, only products registered with the national SII for the fiscal year 2026 are eligible. | 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; if energy management equipment is installed, 150,000 JPY per unit). Expansion of battery units: 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 applications and performance reports will be accepted starting June 30. |
| Chuo Ward “Subsidy for Introduction of Renewable Energy and Energy-Saving Equipment for Residential and Multi-Family Housing” | Residents, owners of rental multi-family housing within the ward, small businesses, and management associations of condominium complexes within the ward. Installation and payment must be completed by March 15, 2027, with completion reports submitted by March 31. Pre-application is required at least two weeks before construction. | General: 100,000 JPY per kW for solar power generation (maximum 350,000 JPY), 10,000 JPY per kWh for battery systems (maximum 100,000 JPY). Participants in “Chuo Eco Act” receive additional amounts (150,000 JPY per kW for solar power, maximum 420,000 JPY; 15,000 JPY per kWh for batteries, maximum 120,000 JPY). |
From April 1, 2026, will end once the budget is exhausted. As of September 30, 2026, the remaining budget ratio is 32.0%, and after reaching 20% remaining, only window applications will be accepted (updated on October 5, 2026). |
| National “DR Home Battery Project” (Fiscal Year 2025 Supplement) | Newly installing home battery systems that can be utilized for DR (demand response). | Calculated based on a standard amount of 34,500 JPY per kWh of initial effective capacity (subsidy rate within 30% and maximum 600,000 JPY per application). | The budget was reached on May 29, 2026, and the public recruitment has ended (there are no plans to reopen public recruitment, and applications cannot be submitted at this time). |
| National “Mirai Eco Housing 2026 Project” (Renovation) | The storage battery is one of the eligible facilities, but it must be combined with essential work such as insulation renovation of windows (openings) and the building structure; installation of the storage battery alone cannot be applied for. Solar panels are not included as eligible facilities | Storage Battery: 96,000 JPY/unit | Applications will end once the budget limit is reached. As of October 5, 2026, the official website indicates that the application amount for renovations is 8% of the budget. Please check the official website for the application status. |
The Tokyo solar power and storage battery subsidy requires prior application. Storage batteries applied for after October 1, 2026, will only be eligible if they are registered products under the national SII program, and the equipment requirements will change. The subsidy in Chuo Ward requires a prior application to be submitted about two weeks before the construction, and the process is to start construction after receiving the notification of grant decision. Each program has different eligibility conditions, application procedures, and whether they can be combined, and applying does not guarantee a grant, so please confirm before contracting and starting construction.
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 Introducing Home Storage Systems for DR Resources)”
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 storage systems of registered products that can be utilized for demand response (DR), and in the fiscal year 2025 supplementary budget, the subsidy amount was 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 that contracts or orders made before the grant decision are not eligible.
However, the fiscal year 2025 supplementary budget applications reached the budget on May 29, 2026, and the public recruitment has ended. The official website also states that there are no plans to resume public recruitment, and applications cannot be made at this time. Please check the official website for future public recruitment.
Additionally, there are currently no subsidies confirmed for the installation of solar panels on existing homes by the national government.
👉 Click here for the official website of the DR Home Storage Battery Project
Tokyo Metropolitan Government “Promotion Project for Introducing Solar Power Generation in Homes”
This subsidy is for those who are installing unused solar power generation systems in residential homes within Tokyo. There is no requirement for simultaneous installation of storage batteries.
●Existing homes: For 3.75 kW or less, 150,000 JPY per kW (maximum 450,000 JPY); for over 3.75 kW to less than 50 kW, 120,000 JPY per kW
●New homes: For 3.6 kW or less, 120,000 JPY per kW (maximum 360,000 JPY); for over 3.6 kW to less than 50 kW, 100,000 JPY per kW
●There are also additional amounts for the installation of rooftop frames and waterproofing work.
The target is to install unused panels with an output of less than 50 kW that have obtained JET certification, in residential homes within Tokyo, and used in living spaces. The process involves making a prior application and then applying for the grant after installation. Starting from the fiscal year 2026 prior application, submission of a certificate issued by a financial institution during the performance report has become mandatory.
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 Introduction 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 recipients are owners of subsidized equipment (excluding national and local governments), and installation must be completed 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)
Chuo Ward “Subsidy for Introduction of Natural Energy and Energy-Saving Equipment for Residential and Multi-Family Housing”
This is a subsidy for those introducing solar power systems and battery systems to residential and multi-family housing within the ward. Before starting construction, pre-application must be made, and the process requires receiving a notification of grant decision before starting work. Eligible recipients include residents, owners of rental multi-family housing within the ward, small and medium-sized enterprises, and management associations of condominium complexes within the ward who bear the costs.
●Solar power system: 100,000 JPY per kW (up to 350,000 JPY)
●Battery system: 10,000 JPY per kWh of storage capacity (up to 100,000 JPY)
●Participants in “Chuo Eco Act” receive additional amounts (solar power is 150,000 JPY per kW, up to 420,000 JPY; battery is 15,000 JPY per kWh, up to 120,000 JPY)
Applications must be submitted about two weeks before the installation work, and installation and payment must be completed by March 15, Reiwa 9, with completion reports submitted by March 31, Reiwa 9. It is noted that if national and Tokyo subsidies are used together, the ward’s subsidy may be reduced.
The official page of Chuo Ward (updated October 5, Reiwa 8) states that acceptance will end once the budget is depleted from April 1, Reiwa 8, and as of September 30, Reiwa 8, the remaining budget ratio is 32.0%. Once the remaining budget reaches 20%, applications will be restricted to in-person submissions only. Since the acceptance status may change, those considering applying should check the official page early.
👉 Here is the official page of Chuo Ward
Solar Panel Installation & Battery Installation Price List
⇧Service Menu | For Costs Related to Solar Panel Installation & Battery Installation, Click Here
⇧Service Menu | For Costs Related to Solar Panel Removal & Water Heater Dismantling, Click Here
Breakdown of Installation Capacity, Equipment, and Construction Costs
The costs for solar panels and batteries should be checked separately as “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.
Understanding Installation Capacity (kW) and 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). 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 installation costs as approximately 800,000 JPY to 1,200,000 JPY for 3 to 5 kW, and 1,200,000 JPY to 1,900,000 JPY for 6 to 10 kW. (These are just estimated amounts and may vary based on wiring length, scaffolding range, existing roofing materials, panel layout, etc.)
▶ Installation Menu | Costs for Solar Panel Installation and Battery Installation
Items to Confirm in the Quotation (Cost Check)
When comparing prices in multiple quotes, it is common to compare different capacities and equipment. Please check if the following items are clearly stated in each company’s quotation!
| 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 confirm if it is a type that controls in conjunction with the battery. |
| 3. Battery | Manufacturer, model number, capacity (kWh), range usable 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 involves drilling holes or clamping). |
| 5. Wiring and Electrical Work | Wiring route and length, work around the distribution board, and whether there is a monitor to check power generation. |
| 6. Roof Reinforcement and Waterproofing | Details of waterproofing treatment at fixed points, and whether necessary roof repairs and substrate reinforcements are included. |
| 7. Applications | How much support is included for applications to the power company, certification for selling electricity (FIT), and subsidy applications. |
| 8. Scaffolding | Scope and quantity of scaffolding. If it is simultaneous with roof work or exterior painting, check 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 disposal costs for waste materials are included. |
| 10. Tax Classification and Warranty | Whether the price is tax-inclusive or tax-exclusive, conditions under which additional costs may arise, and details and duration of manufacturer and workmanship warranties. |
If the capacities differ, both the price and power generation will change. Kakeru Koumuten Co., Ltd. welcome price comparisons, so if you bring quotes from other companies, we will explain the differences item by item!
Self-Quotation and Profit Simulation for Solar Power Generation
With the simulator above,
you can get a rough estimate and income simulation for up to 30 years!
If you know the total installation capacity of solar panels on the roof and the capacity of the storage battery, you can obtain a rough estimate and income simulation!
*The simulation results are estimates. Actual income may vary depending on assumptions such as electricity rates, self-consumption ratios, selling prices, and costs for equipment inspection and replacement.
Customer Feedback
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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 range |
| Base Mounting Hardware Used |
| Niigata Manufacturing / Aluminum Catch Type Hardware |
| Fixing Method & Waterproofing Arrangement |
| Fixed by catching the horizontal metal roof with catch-type hardware (Catch Method) |
| Price Range |
| 2,200,000 JPY～2,300,000 JPY *Due to the subsidy being granted, the actual burden amount is approximately 1,000,000 JPY Estimated recovery period for construction costs: about 8 to 9 years (self-consumption) *The subsidy amount and recovery estimate 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 subsidies are available, and I would like to know how much will be granted. |
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 subsidies to be granted, and we explained this to the customer along with the estimate!
How to Choose a Solar Panel Installation Contractor in Chuo City, Tokyo
There are many solar panel installation contractors available in Chuo City, Tokyo, and you may be unsure which contractor to choose.
Therefore, when requesting solar panel installation and battery storage installation work, let’s confirm the following four points:
● Have extensive knowledge not only about solar panels but also about roofs
● Confirm the presence of warranties and aftercare services
● Obtain estimates from multiple contractors (three companies as a guideline)
● Check if they provide support for subsidy applications
By confirming the above four points, you will be able to choose a reliable contractor.
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 verification of 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 a renovation to detach and reattach the solar panels within a few years
・Misjudgment of the type of waterproofing led to incorrect processing 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 Verification Before Installing Solar Panels” in this article
Confirm the presence of warranties and aftercare services
When choosing a solar installation contractor, let’s confirm the presence of warranties. It is important to check not only the duration of the warranty but also the coverage, exclusions, and cost conditions.
While the solar panels and battery storage units come with manufacturer warranties, it is also essential to check for the presence of a workmanship warranty in case leaks occur after installation!
For contractors that offer workmanship 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 contractors offer aftercare services separate from warranties, so be sure to check if the contractor you are considering has aftercare services.
Changes or damages on the roof may not be visible, so you might not notice them yourself.
By conducting inspections of hidden areas during aftercare maintenance, early detection of issues can help prevent significant repairs or failures!
Kakeru Koumuten Co., Ltd. offers a rain leak warranty as part of the workmanship warranty for solar panel installations. (The warranty for solar panel installations is 10 years, and depending on the condition of the roof before installation, a roof renovation may be required to provide the warranty.)
We also provide aftercare maintenance, sending out annual direct mail!
Please check the DM, and 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 with 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, please check:
“Verification of estimate items”
“Type of solar panel”
“Warranties and after-sales services”
and make detailed comparisons for your judgment! Avoid judging solely based on cost, as using lower-grade materials or skipping processes can reduce costs!
▶ 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 there are deficiencies in the documents, the subsidy may not be granted.
Since there are systems like Tokyo’s subsidies that require prior application, 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 Tokyo’s subsidies, prior application) before proceeding with the construction!
For Tokyo’s subsidies, after installation, you will need to submit a grant application and performance report, which will be reviewed before the grant is awarded! (The flow of procedures varies by system)
▶ To “Subsidies and grants that may be applicable in Chuo Ward, Tokyo” in this article
Benefits of Introducing Solar Equipment
The benefits of introducing solar panels are as follows!
Benefit 1 Economic Benefits
The biggest advantage of introducing solar panels is the economic benefit!
The selling price of 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, and the same price will apply for the 2026 fiscal year. After the fifth year, it tends to be more advantageous to use it at home (self-consumption) rather than selling it, so combining it with a storage battery is also an option.
👉 Ministry of Economy, Trade and Industry | 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 conditions, you may be able to utilize subsidies!
Reducing the actual burden through subsidies is a significant advantage!
In Chuo Ward, there is a possibility of being eligible for the national, Tokyo Metropolitan, and Chuo Ward systems. The Chuo Ward subsidy will end once the budget is exhausted, and as of September 30, Reiwa 8, the remaining budget ratio is reported to be 32.0% (please check the application status for each system).
Advantage 3 Environmentally friendly!
Solar power generation has low carbon dioxide emissions and can reduce dependence on fossil fuels, contributing to the mitigation of global warming.
Solar panels themselves do not produce noise or exhaust gases during the generation process, making them an environmentally friendly method of power generation. (However, devices like power conditioners do have operational noise.)
Advantage 4 Heat insulation effects can be expected!!
By installing panels on the roof or rooftop, they block direct sunlight to the roof.
Especially in summer, it can help reduce the temperature rise of the roof, providing a heat insulation effect!
(Note that this does not improve the building’s insulation performance 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 reinstalling the solar panels.
If the existing roof is deteriorated, 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 ask for a simulation that considers maintenance costs 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 fixtures with screws, etc., to the roofing material and substrate, waterproofing of the fixed parts becomes crucial.
In methods that involve making holes in the roof, the risk of leaks inevitably arises.
Of course, we will ensure proper waterproofing, but if you are concerned about making holes, one option is to replace the roofing material with a metal roof and fix the solar panels using the catch method. (The catch method has compatibility conditions between the roofing material and fixtures, and it cannot be used with all metal roofs.)
Catch-type base fixture exclusively for horizontally laid metal roofs
Point 3 The Roof Becomes Heavier
Installing solar panels will make the roof heavier. After investigating the existing roof, substrate, and load-bearing capacity, switching to a lightweight 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!
How to Choose 1: Compare Based on Total Roof Output
When installing solar panels on the roof, it is important to know how much electricity can be generated in a limited area, and the more electricity generated, the better!
The size and output of solar panels vary by manufacturer.
While a 350W output panel may seem less impressive compared to a 400W output panel, it is essential to consider how well the panel size fits the roof. For example, “20 panels of 350W can be installed” while “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 just the output of a single panel!
*The above calculations are for total output (kW). The actual electricity generation (kWh) will vary based on conditions such as roof orientation, slope, and shading.
How to Choose 2: Compare Based on Degradation Rate of Solar Panels
Solar panels have a degradation rate, and their output gradually decreases over 10 or 20 years.
The degree of output decline 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 electricity generation itself.
By considering the degradation rate along with the initial output, you can choose solar panels without regrets!
How to Choose 3: Compare Based on Warranty Years
Solar panel warranties include various types such as “output warranty,” “natural disaster warranty,” and “system warranty,” and the warranty years differ by manufacturer.
For output warranties, some manufacturers offer a 30-year warranty, while others may only provide a 10-year warranty, so it varies!
Longer warranties are better, so be sure to check the warranty years and conditions of the manufacturers you are considering!
Frequently Asked Questions about Solar Power and Storage Battery Installation in Chuo Ward, Tokyo
We have compiled frequently asked questions from customers considering the installation of solar panels and storage batteries in Chuo City, Tokyo. (Tap to open answers)
How much does it cost to install solar panels and storage batteries in Chuo City, Tokyo?
The cost varies depending on the installation capacity, equipment, and condition of the roof. In the above case study (solar panel 4.3kW + storage battery, completed in April 2025), it was 2.2 million yen to 2.3 million yen.
Estimates by capacity are available on our solar panel and storage battery installation pricing page. We will create a layout diagram from the drawings and on-site survey and provide a free estimate!
Are there any subsidies available for solar and storage battery installation in Chuo City, Tokyo?
As of October 7, 2026, Tokyo’s “Promotion Project for Solar Power Generation in Households” (for existing homes, 15,000 yen per kW for systems under 3.75kW, with a maximum of 450,000 yen) and “Promotion Project for Storage Battery Installation in Households” (100,000 yen per kWh for storage batteries, with a maximum of 1.2 million yen per household) are accepting pre-applications starting May 29, 2026, as listed on the official page of Tokyo (Cool Net Tokyo). In Chuo City, the subsidy for the introduction of natural energy and energy-saving equipment for residential and multi-family housing (general application for solar power generation is 100,000 yen per kW with a maximum of 350,000 yen, and for storage systems, 10,000 yen per kWh with a maximum of 100,000 yen) is currently accepting applications until the budget runs out, as stated on the official page of Chuo City. The national DR household storage battery project has ended 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 subsidy requires a pre-application, and Chuo City’s assistance also requires applications to be submitted approximately two weeks before construction. Conditions such as whether you can sign a contract or start construction before applying differ by program, so please confirm before signing a contract.
The order of procedures varies by program, so please check before signing a contract or starting construction.
Can solar panels be installed on a slate roof? I’m worried about leaks.
Installation on a slate roof is possible, but it requires checking the condition of the roofing material and substrate. The method of securing the panels varies by construction method, and when securing brackets to the roofing material and substrate, waterproofing of the secured areas is crucial.
Kakeru Koumuten is a specialist in exterior renovations with strong expertise in roofing work, so we will check the condition of the roof before installation and suggest methods such as roof overlay or replacement if deterioration is advanced.
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 within 10 to 20 years after installation, the cost of removing and reinstalling the solar panels will be incurred separately. If the remaining lifespan of the roof is short, it may be more cost-effective to renovate to a highly durable roofing material before installation.
Please consult us on how to proceed with the installation after checking the condition of the roof during the on-site survey!
Is it better to install a storage battery together with solar panels?
If you want to use the electricity generated at night or prepare for power outages, simultaneous installation is recommended. The selling price will be 8.3 yen/kWh after the fifth year, making it more advantageous to use the electricity at home rather than selling it.
Additionally, the Tokyo Metropolitan Government’s subsidy for storage batteries (for the 2026 fiscal year, 100,000 yen per kWh, with a maximum of 1,200,000 yen per household) aims to increase the self-consumption of electricity generated by solar power. In Chuo Ward, storage systems are also included in the subsidy program. You can compare “solar power only” and “solar power + storage battery” through a financial simulation.
How many kW can be installed on my roof? Is it okay for north-facing roofs or roofs with shadows?
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.
Chuo Ward is mostly reclaimed land from the Edo period, characterized by flat lowland areas. The shape and orientation of the roof, as well as the shadows cast by surrounding buildings, will differ for each house. You can check the estimated power generation through the power generation simulation.
How long does the construction period take?
In the above construction example (solar panel 4.3 kW + storage battery), it took about 3 days. The duration may vary depending on whether roof work is done simultaneously and the shape and installation capacity of the roof.
Additionally, please note that there will be a separate period required for applying for subsidies and 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 4 years, and 8.3 yen/kWh from the 5th to the 10th year, with the same price applying for the 2026 fiscal year.
The idea is to recover initial costs more quickly in the first four years and then focus on self-consumption. Kakeru Koumuten provides a financial simulation that takes into account 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 customers who wish to have inspections. We can also clean solar panels using a special brush if power generation decreases due to dirt.
Since the roof is a place that is difficult to check by yourself, please feel free to consult us if you have any concerns.
Can you also handle renovations for roofs that already have solar panels installed?
Yes, we can. Kakeru Koumuten can detach and reattach solar panels in-house, allowing us to remove the panels, perform roof overlay (cover method) or re-roofing, and then reinstall them in a consistent manner. The removed panels can be stored in our own warehouse.
For costs, please refer to the solar panel removal and hot water heater removal pricing page.
If you are looking for a solar panel installation contractor in Chuo City, Tokyo, please consult Kakeru Koumuten Co., Ltd.
Our company handles a wide range of exterior renovations, including solar panels, roof work, and exterior wall work in Chuo City, Tokyo.
We receive requests from many customers, including renovation companies and real estate agencies, who have contacted us!
Kakeru Koumuten Co., Ltd. promises “high-quality renovations at low cost”, and we have received great feedback from numerous customers.
We continue to update our annual construction achievements and will strive to improve quality to satisfy even more customers in the future.
Our company can perform all exterior renovations, not only roof overlay work and re-roofing but also partial roof repairs, exterior painting, and exterior cover methods.
We are also happy to handle 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 about recommended solar panels”, “I want to keep costs as low 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 the customer’s position and will propose the best construction plan!
We are confident that we will not be outdone by other companies in terms of cost, quality, and organization for exterior work!
We are confident, so we welcome competitive quotes!
Estimates are completely free, and if our company is found to be inferior to others, you are free to decline!
Characteristics of Chuo City, Tokyo, and Points for Solar Work
Chuo City covers an area of 10.115 square kilometers, bordered by the Sumida River to the east, with Koto City and Sumida City, and facing Tokyo Bay to the south. Most of the area is land reclaimed after the Edo period, characterized as a low-lying area with very little elevation. We have summarized the characteristics of the terrain in Chuo City, Tokyo, and points to consider when installing solar panels and storage batteries below. (Tap to open)
View the characteristics of Chuo City, Tokyo, and points for solar work
■ Low-lying reclaimed land. Check scaffolding, delivery, and shadows for each site
The official page of the ward introduces that the area is approximately 3 kilometers long from east to west and about 5.5 kilometers from north to south. Even within this compact ward, the size of the site, the distance from adjacent buildings, and the width of the front road vary from one house to another, affecting the space for scaffolding, the route for equipment delivery, and the shadow cast by neighboring buildings. Additionally, there are condominium buildings in the ward, and the ward’s subsidies also apply to management associations. At Kakeru Koumuten, our own scaffolding team plans the scaffolding according to the site conditions, creates layout drawings from the blueprints and site surveys, and you can confirm them through a power generation simulation.
■ Check the flood and storm surge hazard maps. Pay attention to the installation location of equipment.
The hazard map for Chuo Ward includes the Sumida River, Kanda River, and Nihonbashi River version (with a maximum expected total rainfall of 690 millimeters and maximum hourly rainfall of 153 millimeters) and the Arakawa version (with an average total rainfall of 632 millimeters over three days in the basin), and for storm surges, it refers to the storm surge inundation area map published by Tokyo Metropolis. Depending on where the power conditioner and storage battery are installed, separate from the panels on the roof, the impact during flooding may vary. Please check the inundation assumptions for your residence on the ward’s hazard map and consult with us about the installation location and height in conjunction with the installation conditions of the manufacturer you are using.
■ The types of roofs and their ages vary from house to house. Check the roof and waterproofing before installation.
Even within the same ward, the types of roofs, their ages, and the shapes of the sites vary from one house to another. At Kakeru Koumuten, we will confirm the type and condition of the roof and the situation of the site before installation and propose the 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 approximately 1,927 hours, with January (about 193 hours) having the most and June during the rainy season (about 124 hours) having the least. (This is a reference value, not an observation value within Chuo Ward.)
The power generation amount in Chuo Ward can also be affected by shadows from surrounding buildings, so conducting a year-round power generation simulation and selecting the capacity of the storage battery according to the times when electricity is used the most are key points.
Our company handles many exterior construction and solar power projects in Chuo Ward, 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 Chuo Ward, Tokyo
Kakeru Koumuten accepts requests throughout Kanagawa Prefecture and all of Tokyo.
List of Areas in Chuo Ward, Tokyo
Akashicho, Chuo Ward / Irifune, Chuo Ward / Kachidoki, Chuo Ward / Kyobashi, Chuo Ward / Ginza, Chuo Ward / Shinkawa, Chuo Ward / Shintomi, Chuo Ward / Tsukishima, Chuo Ward / Tsukiji, Chuo Ward / Tsukuda, Chuo Ward / Toyosu, Chuo Ward / Nihonbashi, Chuo Ward / Nihonbashi Odendama-cho, Chuo Ward / Nihonbashi Kakigaracho, Chuo Ward / Nihonbashi Kabuto-cho, Chuo Ward / Nihonbashi Kayabacho, Chuo Ward / Nihonbashi Koamicho, Chuo Ward / Nihonbashi Kodenmacho, Chuo Ward / Nihonbashi Kobunacho, Chuo Ward / Nihonbashi Tomizawacho, Chuo Ward / Nihonbashi Nakasu, Chuo Ward / Nihonbashi Ningyocho, Chuo Ward / Nihonbashi Hakozaki-cho, Chuo Ward / Nihonbashi Hamacho, Chuo Ward / Nihonbashi Bakurocho, Chuo Ward / Nihonbashi Hisamatsu-cho, Chuo Ward / Nihonbashi Horidome-cho, Chuo Ward / Nihonbashi Honishicho, Chuo Ward / Nihonbashi Honmachi, Chuo Ward / Nihonbashi Muromachi, Chuo Ward / Nihonbashi Yokoyamacho, Chuo Ward / Hatchobori, Chuo Ward / Hamarikyu Gardens, Chuo Ward / Harumi, Chuo Ward / Higashi Nihonbashi, Chuo Ward / Minato, Chuo Ward / Yaesu, Chuo Ward
・Trust Kakeru Koumuten for exterior wall painting in Chuo City, Tokyo!
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・Trust Kakeru Koumuten for exterior renovations in Chuo City, 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 comparison estimates and key points!
・Top 12 solar power generation manufacturers! Features and selection tips included!
・What are the costs of solar power generation? Comprehensive tips to reduce costs!
・What are the best locations for solar power installation? Key points for site selection included!
・Check out our 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!
