Leave Your Solar Panel Installation Work in Komae City, Tokyo to Kakeru Koumuten Co., Ltd.!
For solar panel and storage battery installation in
Komae City, Tokyo,
trust Kakeru Koumuten!
Kakeru Koumuten is a company specializing in exterior renovations.
As a strong company in roofing work, we are entrusted withsolar panel installation and storage battery installation considering roofing and waterproofing!
“How to Choose a Solar Panel Contractor in Komae City, Tokyo”
“Costs for Solar Panel and Storage Battery Installation”
“Subsidies Available for Solar System Installation in Komae City, Tokyo”
We will also explain the above three points!
Installing solar panels carries risks such as“the occurrence of leaks” and other troubles.
To ensure a satisfactory solar panel installation, we recommend obtainingthree or so estimates!
Table of Contents (tap to open/close)
- Reasons Why Kakeru Koumuten is Chosen for Solar Panel Installation in Komae City, Tokyo
- Roof Inspection Before Installing Solar Panels
- Subsidies and Grants That May Be Available in Komae City, Tokyo
- Price List for Solar Panel and Storage Battery Installation
- Breakdown of Installation Capacity, Equipment, and Construction Costs
- Self-Estimate and Profit and Loss Simulator for Solar Power Generation
- Customer Testimonials
- Case Studies of Solar Panel Installations
- How to Choose a Solar Panel Installation Company in Komae 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 Storage Battery Installation in Komae City, Tokyo
- If You Are Looking for a Solar Panel Installation Company in Komae City, Tokyo, Contact Kakeru Koumuten
- Characteristics of Komae City, Tokyo and Points for Solar Construction
- Service Area in Komae City, Tokyo
Reasons Why Kakeru Koumuten is Chosen for Solar Panel Installation in Komae City, Tokyo
Regarding why our company is entrusted with solar panel installation by customers in Komae 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 Can Also Handle Exterior Renovations Other Than 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 and issues after installation!
Kakeru Koumuten Co., Ltd. specializes in roofing work and can also detach and attach solar panels in-house, allowing for quick responses to maintenance and urgent issues 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 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 we can assemble the scaffolding in-house.
By not outsourcing scaffolding work and using 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 can purchase materials at a lower cost!
Additionally, we always have a stock of roofing materials, so we can respond quickly in emergencies!
In-house sorting and transportation of waste materials
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 attached to the 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 each other, we also have samples of roofing materials and models that show the structure, allowing us to provide 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 Kakeru Koumuten handle everything from inquiries to project completion in a consistent manner, we can keep costs down and provide high-quality roof renovations.
Additionally, one representative will assist you from the estimate to the completion of the work.
Since the same person will handle sales and 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, ensuring confidence in our construction techniques.
We are capable of handling large-scale roof projects for factories and other facilities!
5. Warranty and Aftercare
In addition to the manufacturer’s warranty for solar panel installation work, our own construction warranty (leak warranty) is also included!
(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.
If you are unable to 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 improve 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 conduct technical training to ensure that all staff 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 construction 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 construction 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, which specializes 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 roof renovation first. |
| 2. Condition of Substrate and Waterproof Sheet | If the sheathing boards or roofing (waterproof sheet) under the roofing material are damaged, it will affect the fixing strength of the fittings 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 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 that can be installed (installation capacity) is determined by 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 fixing or using fittings 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. Location of Equipment Installation and Wiring | We will check the installation locations for the power conditioner and storage battery, as well as the wiring route to the distribution board. The length of the wiring will also affect costs. |
| 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. We will also check the width of the front road and any steps on the site during the on-site investigation. |
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 suited to 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 methods to replace with lightweight roofing materials 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, 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 renovate the roof 10 to 20 years after installation, there will be additional costs for removing and reinstalling 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, so please consult us according to the condition of your roof!
▶ Click here for roof renovations in Komae City, Tokyo
PossibleSubsidies and Grants in Komae City, Tokyo
If you are introducing solar panels or storage batteries in Komae City, Tokyo, the systems from the “National Government,” “Tokyo Metropolitan Government,” and your local “Komae City” may be applicable.
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 “Solar Power Generation Promotion Project for Households” | Individuals, corporations, or management associations installing a new unused solar power generation system (output under 50kW, JET certification, etc.) in residential properties within Tokyo. The generated power must be used in the living area. Pre-application is required. | Existing homes: 15,000 JPY per kW for systems up to 3.75 kW (maximum 450,000 JPY), 12,000 JPY per kW for systems over 3.75 kW and under 50 kW. New homes: 12,000 JPY per kW for systems up to 3.6 kW (maximum 360,000 JPY), 10,000 JPY per kW for systems over 3.6 kW. |
For the 2026 fiscal year, pre-applications are being accepted from May 29 (will end once the budget is reached). From the pre-application for the 2026 fiscal year, submission of a certificate issued by a financial institution is mandatory at the time of performance reporting. |
| Tokyo “Battery Storage Promotion Project for Households” | Owners of eligible devices (battery storage 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 2026 fiscal year are eligible. | Battery storage package: 100,000 JPY per kWh (maximum 1,200,000 JPY per household). Additional incentive for participating in DR demonstration (100,000 JPY per unit; 150,000 JPY per unit if energy management equipment is installed). Expansion of battery storage unit: 60,000 JPY per kWh (maximum 720,000 JPY per household). |
For the 2026 fiscal year, pre-applications are being accepted from May 29. Grant applications and performance reports will be accepted starting June 30. |
| Komae City “Global Warming Countermeasure Equipment Installation Subsidy” (2026 fiscal year) | Individuals (residents), joint housing (owners, management associations), and businesses are eligible, provided there are no tax delinquencies. Application is required before installation, and installations completed before grant approval are not eligible. | Solar power generation (purchase): 20,000 JPY per kW (maximum 80,000 JPY). Battery storage (purchase): 50,000 JPY. High-insulation windows: 50,000 JPY (100,000 JPY if installed alongside solar power generation). Fuel cells: 50,000 JPY. |
Applications started on April 1, 2026, and were closed on September 8, 2026, as the budget limit was reached, as stated on Komae City’s official page. |
| National “DR Household Battery Storage Project” (2025 fiscal year supplementary) | New installation of household battery 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 30% and a maximum of 600,000 JPY per application). | As of May 29, 2026, the budget has been reached, and the public offering has ended (there are no plans to reopen the public offering, and applications cannot be made at this time). |
| National “Mirai Eco Housing 2026 Project” (Renovation) | Battery storage is one of the eligible facilities, but it must be combined with essential works such as insulation renovation of windows (openings) and the building structure; applications cannot be made for battery storage installation alone. Solar panels are not included as eligible facilities. | Storage Battery: 96,000 JPY/unit | Ends as soon as 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 site. Please check the application status on the official site. |
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 equipment requirements will change. The subsidy in Komae City requires an application before the installation of equipment, and the budget limit for the fiscal year 2026 has been reached, ending the acceptance. Eligibility conditions, application procedures, and the possibility of combining with other programs vary by system, and it is not guaranteed that a subsidy will be granted upon application, so please confirm before contracting and starting work.
Kakeru Koumuten will guide you on the eligibility conditions and application periods for each program after confirming them.
National Subsidy “DR Home Storage Battery Project (Support for the Introduction of 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 newly introducing registered storage systems that can be utilized for demand response (DR), and in the fiscal year 2025 supplementary project, 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 also conditions such as being ineligible for those contracted or ordered before the grant decision.
However, the fiscal year 2025 supplementary application amount reached the budget on May 29, 2026, and the public recruitment has ended. The official site also states that there are no plans to reopen the public recruitment, and applications cannot be made at this time. Please check the official site for future public recruitment.
Furthermore, there are currently no subsidies confirmed for the installation of solar panels on existing homes.
👉 Click here for the DR Home Storage Battery Project official site
Tokyo “Promotion Project for the Introduction of Solar Power Generation in Homes”
This subsidy is for those installing unused solar power generation systems in residential homes in Tokyo. The simultaneous installation of storage batteries is not a condition.
●Existing Homes: For up to 3.75 kW, 150,000 JPY per kW (maximum 450,000 JPY); for over 3.75 kW and under 50 kW, 120,000 JPY per kW
●New Homes: For up to 3.6 kW, 120,000 JPY per kW (maximum 360,000 JPY); for over 3.6 kW and under 50 kW, 100,000 JPY per kW
●There are also additions 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, used in the residential part of homes in Tokyo. The process involves making a prior application and then applying for the grant after installation, and starting from the prior application for the fiscal year 2026, submission of a certificate issued by a financial institution at the time of performance reporting 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 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 Unit: 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 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 with the national SII for the fiscal year Reiwa 8 will be eligible.
The official page of Tokyo states that pre-registration is being accepted from May 29, Reiwa 8. For detailed conditions such as combinations with solar power generation, please check the official page.
👉 Here is the official page of Tokyo (Cool Net Tokyo)
Komae City “Subsidy for Equipment Installation for Global Warming Countermeasures” (Fiscal Year Reiwa 8)
Komae City’s “Subsidy for Equipment Installation for Global Warming Countermeasures” provides assistance for individuals (residents), condominiums (owners and management associations), and businesses within the city when installing equipment such as solar power generation and batteries. Conditions include no delinquency in city taxes, and it is necessary to apply before the installation of the equipment. If the installation is done before the grant decision, it will not be eligible, as stated on the city’s official page.
●Solar Power Generation (purchase): 20,000 JPY per kW (maximum limit 80,000 JPY)
●Battery (purchase): 50,000 JPY
●High Insulation Windows: 50,000 JPY (100,000 JPY if installed together with solar power generation)
●Fuel Cells: 50,000 JPY
For fiscal year Reiwa 8, applications started on April 1, Reiwa 8, and the application was closed as the budget limit was reached at 5 PM on September 8, Reiwa 8, as stated on Komae City’s official page (confirmed as of October 7, 2026). The details for the next fiscal year are not posted on the official page, so if you are considering applying, please check the latest information on the city’s official page.
Conditions for eligible equipment and application methods may change.
👉 Here is the official page of Komae City
Solar Panel Installation & Battery Installation Price List
⇧Service Menu | For Costs of Solar Panel Installation and Battery Installation, Click Here
⇧Service Menu | For Costs of Solar Panel Removal and Water Heater Removal, Click Here
Breakdown of Installation Capacity, Equipment, and Construction Costs
The costs for solar panels and batteries should be checked separately for “Equipment Costs (Equipment Price)” 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 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 (kilowatts). Batteries are compared based on the amount of electricity they can store, expressed in kWh (kilowatt-hours).
The amount of kW that can be installed on a roof varies for each house based on the roof’s shape, orientation, and size. 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 panels as approximately 800,000 yen to 1,200,000 yen for 3-5 kW and 1,200,000 yen to 1,900,000 yen for 6-10 kW. (These are just approximate amounts and may vary based on wiring length, scaffolding range, existing roofing materials, panel layout, etc.)
▶ Service Menu | For Costs of Solar Panel Installation and Battery Installation, Click Here
Items to Confirm in the Estimate (Cost Confirmation)
When comparing estimates, it’s common to compare different capacities and equipment. 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). |
| 2. Power Conditioner | Manufacturer, model number, capacity, number of units, installation location (indoor/outdoor). Also confirm whether it is a type that controls with a battery. |
| 3. Battery | Manufacturer, model number, capacity (kWh), usable range during power outages (entire house or specific circuits), installation location. |
| 4. Mounting Frame and Fittings | Name of fittings suitable for roofing materials and method of securing (whether it involves drilling holes or clamping). |
| 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 fixed points, whether necessary roof repairs and substrate reinforcements are included. |
| 7. Applications | Extent of support for applications to the power company, certification applications for selling electricity (FIT), and subsidy applications. |
| 8. Scaffolding | Scope and quantity of scaffolding. If roof work and exterior painting are done simultaneously, confirm that the same scope and quantity are not counted twice. |
| 9. Removal and Disposal | Whether the removal of existing solar thermal water heaters and old panels, as well as disposal costs for waste materials, are included. |
| 10. Tax Classification and Warranty | Whether prices are tax-inclusive or exclusive, conditions under which additional costs may arise, details and duration of manufacturer and workmanship warranties. |
Differences in capacity will change both the price and power generation. Kakeru Koumuten Co., Ltd. welcome comparisons, so if you bring estimates from other companies, we will explain the differences item by item!
Self-Estimate and Profit Simulation for Solar Power Generation
With the simulator above,
you can obtain a rough 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 get a rough estimate and profit simulation!
*The simulation results are approximate. Actual profits may vary based on assumptions such as electricity rates, self-consumption ratios, selling prices, and costs for equipment inspection or replacement.
Customer Testimonials
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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 Installation
| 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 Manufactured / 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 grant, 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 estimate are based on the system and calculations at the time of construction, and may differ under the current system. |
| Construction Period |
| About 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 can 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 the grant, so we explained it to the customer along with the estimate!
How to Choose a Solar Panel Installation Contractor in Komae City, Tokyo
There are many solar panel installation contractors available in Komae 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:
● Ensure they have extensive knowledge not only about solar panels but also about roofs
● Confirm the presence of warranties and after-sales maintenance
● 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
Improper installation of solar panels can 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
・Installing solar panels on a severely deteriorated roof, leading to leaks
・Installing solar panels on a roof with a short lifespan, resulting in the need for renovations to detach and reattach the solar panels within a few years
・Misjudging the type of waterproofing and applying incorrect treatment, causing leaks
and more
When installing solar panels, understanding the condition and type of the existing roof allows you to avoid unnecessary expenses and unexpected troubles.
▶ Go to “Roof Verification Before Installing Solar Panels” in this article
Confirm the presence of warranties and after-sales maintenance
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, disclaimers, and cost conditions.
Solar panels and battery storage units come with manufacturer warranties, but also check for the presence of a workmanship warranty in case leaks occur after installation!
For contractors that offer a workmanship warranty, if leaks occur after installation, they may cover the repairs under the warranty if it falls within the warranty period and conditions.
Additionally, some contractors offer after-sales services separate from warranties, so make sure to check if the contractor you are considering has after-sales service.
Since abnormalities or damages on the roof may not be visible, you might not notice them yourself.
By conducting inspections of hidden areas during after-sales maintenance, you can more easily prevent significant repairs or failures by detecting abnormalities early!
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, it may not be possible to provide a warranty without performing roof renovations.)
We also provide aftercare maintenance and send out annual DM!
If you check the DM and wish to proceed, we will visit for aftercare maintenance!
Obtain estimates from multiple contractors (3 companies as a guideline)
When requesting solar panel installation, be sure to 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 your desired contractor at a lower price, we recommend obtaining estimates from multiple contractors.
When comparing estimates, please check:
“Verification of estimate items”
“Types of solar panels”
“Warranties and after-sales services”
and make a detailed comparison! 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!
▶ To “Breakdown of installation capacity, equipment, and construction costs” in this article
Confirm whether they provide support for subsidy applications
There may be subsidies available for solar panel installations and battery installations, but if the order of procedures is incorrect or if there are deficiencies in the documents, the grant may not be awarded.
Since there are systems that require prior application, such as the Tokyo Metropolitan Government’s subsidies, it is reassuring to have a contractor who can assist with the preparation of necessary documents and the flow of procedures.
Complete the procedures specified for each system (for Tokyo’s subsidies, prior application is required) 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 Komae City, 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!
Although the selling price of electricity has decreased compared to ten years ago, you can gain benefits by reducing the electricity you buy from the power company by consuming the electricity you generate yourself!
As electricity costs 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 (less than 10kW) will be set at “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 is often more advantageous to use it at home (self-consume) rather than sell it, making a combination with a storage battery a viable option.
👉 Ministry of Economy, Trade and Industry | For purchase prices and periods, click here
Advantage 2 Subsidies can be utilized!
Subsidy conditions and amounts vary by prefecture and municipality, but if you meet the conditions, you may be able to utilize subsidies!
Reducing the actual burden amount through subsidies is a significant advantage!
In the case of Komae City, it is possible that the national, Tokyo Metropolitan, and Komae City systems may apply. Komae City’s grant requires an application before installation, but it has been reported that the budget limit for the 2026 fiscal year has been reached, and applications are now closed (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 such as 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 from hitting the roof.
Especially in summer, this 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 becomes 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.
(Note that 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 a roof renovation 10 to 20 years later, there will be costs for removing and reattaching 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 is reassuring to ask for a simulation that considers maintenance costs before introducing solar panels!
Point 2 The risk of leaks may increase depending on the roofing material
The fixing methods for slate roofs and tile roofs vary by construction method, but in methods that fix hardware to the roofing material or substrate with screws, waterproofing of the fixed parts is crucial.
In methods that create holes in the roof, the risk of leaks inevitably occurs.
Of course, we will ensure proper 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 hardware specifically for horizontal metal roofs
Point 3 The Roof Becomes Heavier
Installing solar panels will make the roof heavier. After investigating the existing roof, substrate, and load capacity, replacing it with 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 consider how much electricity can be generated in a limited area, and the more electricity generated, the better!
Solar panels come in various sizes and outputs depending on the manufacturer.
A 350W output panel and a 400W output panel may seem like the higher output panel is better at first glance.
However, if the size of the panels does not fit well on the roof, there may be cases where “20 panels of 350W can be installed” and “15 panels of 400W can be installed,” resulting in different numbers of panels that can be installed on the same roof due to size differences.
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 calculations are for total output (kW). The actual electricity generation (kWh) will vary depending 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 years and 20 years.
The degree of output reduction after long-term use varies by product. The manufacturer’s output guarantee values are standard figures for warranty purposes and do not indicate the actual degradation rate or electricity generation itself.
By not deciding solely based on initial output and considering the degradation rate, you can choose solar panels without regrets!
How to Choose 3: Compare Based on 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 output warranties, some manufacturers offer a 30-year warranty while others offer a 10-year warranty, so it varies!
Longer warranties are better, so be sure to check the warranty periods and conditions of the manufacturers you are considering!
Frequently Asked Questions about Solar and Storage Battery Installation in Komae City, Tokyo
We have compiled frequently asked questions from customers considering the installation of solar panels and storage batteries in Komae City, Tokyo. (Tap to open answers)
How much does it cost to install solar panels and storage batteries in Komae City, Tokyo?
The cost varies depending on the installation capacity, equipment, and condition of the roof. In the above construction example (solar panel 4.3kW + storage battery, completed in April 2025), it was 2.2 million yen to 2.3 million yen.
Guidelines for different capacities are published on the solar panel and storage 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 and storage battery installation in Komae 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 Tokyo (Cool Net Tokyo) page. Komae City offers a subsidy for equipment installation to combat global warming (20,000 yen per kW for solar power with a limit of 80,000 yen, and 50,000 yen for storage batteries), but as of September 8, 2026, the budget limit has been reached and applications have closed, as stated on Komae City’s official page. 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?
It varies by program. Tokyo’s subsidies require pre-application, and Komae City’s grants also require application before the installation of equipment. 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.
It is possible to install on a slate roof, but it is necessary to check the condition of the roofing material and substrate. The method of securing varies by construction method, and if using a method that secures brackets to the roofing material or substrate, waterproofing treatment of the fixed parts is crucial.
Kakeru Koumuten 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 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 10 to 20 years after installation, the cost of removing and reinstalling solar panels will be incurred separately. 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 on how to proceed with the installation after checking the condition of the roof during the site survey!
Is it better to install a storage battery together with solar panels?
If you want to use generated electricity 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 it at home rather than selling it.
Additionally, the Tokyo Metropolitan Government’s subsidy for storage batteries (for Reiwa 8, it is 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. The subsidy program in Komae City also includes storage batteries (50,000 yen for purchases) as eligible (applications for Reiwa 8 have ended). 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 generation simulation.
Komae City is located in the area where the Tama River flows on the south side of the city, and the shape and orientation of the roof, as well as the shadows cast by surrounding buildings, vary for each house. You can check the expected generation amount through the 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 if roof work is performed simultaneously or depending on the shape of the roof and installation capacity.
Please note that additional time is required for applications for subsidies and power companies, so please consult us as soon as possible.
What is the current selling price (FIT)?
For residential use (under 10 kW), the selling price will be 24 yen/kWh for the first 4 years and 8.3 yen/kWh from the 5th to the 10th year for certifications after October 2025, and the same price will apply in the 2026 fiscal year.
The idea is to recover initial costs quickly in the first 4 years and then focus on self-consumption. Kakeru Koumuten provides a financial simulation that takes into account loan interest rates and electricity rates.
Can you handle maintenance and inspections after installation?
Yes, we can. Kakeru Koumuten sends out annual after-maintenance notices via DM and visits customers who wish to have inspections. We can also clean solar panels using a special brush if the generation amount 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 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 consistently. The removed panels can be stored in our own warehouse.
For costs, please refer to the solar panel removal and water heater removal pricing page.
If you are looking for a solar panel installation company in Komae City, Tokyo, please consult Kakeru Koumuten Co., Ltd.
Our company handles a wide range of exterior renovations, including solar panel installations, roofing work, and exterior wall work in Komae City, Tokyo.
We receive requests from many customers, including renovation companies and real estate agencies, who have contacted us!
Kakeru Koumuten promises “high-quality renovations at low costs”, and we have received positive 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 cover installations for exterior walls.
We are also happy to handle small jobs like partial repairs and rain gutter cleaning!
In urgent cases such as leak repairs, we may be able to provide emergency 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 down as much as possible”, “I just want an estimate for now”, we will provide optimal 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 plans!
We are confident that we will not be outdone by other companies in terms of cost, quality, and efficiency in exterior construction!
We welcome competitive estimates with confidence!
Estimates are completely free, and if you find our company lacking compared to others, feel free to decline!
Characteristics of Komae City, Tokyo, and Points for Solar Construction
Komae City is bordered by Setagaya Ward to the east, Chofu City to the west and north, and Kawasaki City in Kanagawa Prefecture to the south, separated by the Tama River, with an area of 6.39 square kilometers (2,940 meters east-west and 3,660 meters north-south), as stated on the city’s official page. We have summarized the characteristics of Komae City, Tokyo, and points to consider when installing solar panels and storage batteries below. (Tap to open)
View the characteristics of Komae City, Tokyo, and points for solar construction
■ The city area is approximately 2.9 kilometers east-west and 3.7 kilometers north-south. Check the delivery routes for each site
The city area is not large, and the width of the front road, the distance between neighboring houses, and the elevation differences of the site vary from one house to another. The setup of scaffolding and the delivery routes for panels and storage batteries will be confirmed on-site. At Kakeru Koumuten, our in-house scaffolding team plans the scaffolding according to the site, creates layout diagrams from blueprints and on-site surveys, and you can confirm this with a power generation simulation.
■ Check the flood and internal water hazard maps for the Tama River, Nogawa River, and Iruma River. Be cautious about the installation locations of equipment
Komae City’s disaster prevention map and hazard map include flood (the Tamagawa River flood version assumes a total rainfall of 588 millimeters over 48 hours, and the Nogawa and Iruma River flood version assumes a maximum rainfall of 153 millimeters over 1 hour and a total rainfall of 690 millimeters over 24 hours, representing the maximum possible rainfall), internal water, and landslide warning areas (updated April 16, 2026). The placement of power conditioners and storage batteries, separate from the panels on the roof, may affect their performance during water damage depending on where they are installed indoors or outdoors. Please check the assumptions for your location on the city map and consult with us regarding the installation location and height, in accordance with the installation conditions of the manufacturer you are using.
■ Roof types and ages vary from house to house. Check the roof and waterproofing before installation
Even within the same city, the types of roofs, ages, and shapes of the properties vary from house to house. The capacity and fixing methods that can be installed depend on the shape and orientation of the roof, as well as the roofing materials used. At Kakeru Koumuten, we will check the type and condition of the roof and the situation of the property before installation and propose the fixing method, waterproofing details, and scaffolding plan.
■ The annual sunshine hours at the Tokyo Observatory is about 1,927 hours
According to the Japan Meteorological Agency’s average values (1991-2020), the annual sunshine hours at the Tokyo Observatory is about 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 based on observations in Komae City.)
The power generation in Komae City can also be affected by the shadows of surrounding buildings and trees, so it is important to conduct annual power generation simulations and choose the capacity of the storage battery to match the times of high electricity usage.
Our company handles many exterior construction and solar projects in Komae City, 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 Komae City, Tokyo
Kakeru Koumuten accepts requests throughout Kanagawa Prefecture and all of Tokyo.
List of Areas in Komae City, Tokyo
Izumi Honcho, Komae City / Inokata, Komae City / Iwato Minami, Komae City / Iwato Kita, Komae City / Komai Cho, Komae City / Naka Izumi, Komae City / Nishi Izumi, Komae City / Nishi Nogawa, Komae City / Higashi Izumi, Komae City / Higashi Nogawa, Komae City / Moto Izumi, Komae City
・Trust Kakeru Koumuten for exterior wall painting in Komae City, Tokyo!
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・Trust Kakeru Koumuten for exterior renovations in Komae City, Tokyo!
・Kakeru Koumuten Co., Ltd. project achievements
・Kakeru Koumuten Co., Ltd. aftercare services
・Kakeru Koumuten Co., Ltd. service menu and pricing
・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? 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!
