Leave Your Solar Panel Installation Work in Setagaya, Tokyo to Kakeru Koumuten Co., Ltd.!
For solar panel and storage battery installation in
Setagaya, 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 withsolar panel installation and storage battery work that considers roofing and waterproofing!
“How to Choose a Solar Panel Contractor in Setagaya, Tokyo”
“Costs for Solar Panel and Storage Battery Installation”
“Subsidies Available for Solar System Installation in Setagaya, 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 you do not regret your 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 Setagaya, Tokyo
- Roof Inspection Before Installing Solar Panels
- Possible Subsidies and Grants Available in Setagaya, Tokyo
- Price List for Solar Panel and Storage Battery Installation
- Breakdown of Installation Capacity, Equipment, and Construction Costs
- Self-Estimate and Profit Simulation for Solar Power Generation
- Customer Testimonials
- Case Studies of Solar Panel Installations
- How to Choose a Solar Panel Installer in Setagaya, 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 Setagaya, Tokyo
- If You Are Looking for a Solar Panel Installer in Setagaya, Tokyo, Contact Kakeru Koumuten
- Characteristics of Setagaya, Tokyo and Points for Solar Installation
- Service Area in Setagaya, Tokyo
Reasons Why Kakeru Koumuten is Chosen for Solar Panel Installation in Setagaya, Tokyo
Regarding why our company is entrusted with solar panel installation by customers in Setagaya, Tokyo,
“Our Unique Strengths in Solar Panel Installation That Others Cannot Imitate”
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 Beyond 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 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 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 solar work and exterior renovations at low cost and high quality.
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 cut costs for scaffolding construction.
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 canpurchase materials at a lower cost!
Additionally, we always have a stock of roofing materials, so we canrespond 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 installed on roofing materials!
Simulations for potential earnings and installation costs when introducing solar panels are also available!
Since roofing and exterior wall work often accompany these projects, we also provide samples of roofing materials and models that explain the structure in detail!
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 manage everything from inquiries to project completion in a consistent manner, we can keep costs down while providing high-quality roof renovations.
Additionally, one representative will handle everything from the estimate to project completion.
Since the same person is responsible for 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 permits for the construction industry and for the collection and transportation of industrial waste!
We also have nationally certified sheet metal workers and painting specialists on staff, and we are confident in our construction techniques.
We are capable of handling large-scale roof projects such as those for factories!
5. Warranty and Aftercare
In addition to the manufacturer’s warranty for solar panel installation, we also provide our own construction warranty (leakage warranty)!
(The construction warranty for solar panel installation is 10 years. Depending on the condition of the roof before installation, we may not be able to provide a warranty unless 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 altitudes, 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 with a specialized brush.
We will respond according to your wishes.
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 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 construction guidebook” and “profit and loss simulations” that take into account loan interest rates and electricity costs.
Profit and loss simulations can be created for projected cumulative profits and losses over 20 to 30 years.
Even customers who are not familiar with solar construction will receive materials that clearly summarize 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 materials 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 materials is damaged, it will affect the fixing strength of the fittings and waterproofing. We will also check for any signs of water leakage. |
| 3. Orientation, Slope, and Shadows of the Roof | The orientation and slope of the roof surface, as well as shadows from neighboring houses, trees, and utility poles, will affect the power generation. We will create a layout diagram from the drawings and the site, and you can check 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. The number of panels that can be installed varies depending on the size of the panels, so we will compare based on the total output of the roof. |
| 5. Fixing Method and Waterproofing Details | We will confirm whether the method involves drilling holes in the roofing materials for fixing or using fittings to secure the roofing materials. 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 placed on it. After investigating the existing roof, substrate, and load-bearing capacity, switching to lighter roofing materials may also be an option if necessary. |
| 7. Installation Location of Equipment and Wiring | We will check the installation location of the power conditioner and storage battery, as well as the wiring route to the distribution board. The length of the wiring will also affect the cost. |
| 8. Ease of Scaffolding Setup and Delivery Routes | If there 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 level 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 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 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 available. |
| Flat Roof / Rooftop | Fixed by installing a frame | Type and deterioration status of the waterproof layer, waterproofing around the frame. Consider in conjunction with the timing of waterproofing work. |
If you perform roof renovations 10 to 20 years after installation, 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 Setagaya, Tokyo
Potential Subsidies and Grants in Setagaya, Tokyo
If you are introducing solar panels or storage batteries in Setagaya, Tokyo, there is a possibility that national and Tokyo metropolitan programs may apply. In Setagaya, the Eco Housing Subsidy for Reiwa 8 does not cover solar panels or storage batteries.
The following information is based on the official pages of each program as of October 7, 2026. The acceptance status may change depending on the budget, so please check the latest information before contracting or starting work.
Eligibility Conditions and Application 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 system (output less than 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 up to 3.75 kW (maximum 450,000 JPY), 12,000 JPY per kW for over 3.75 kW to under 50 kW. New homes: 12,000 JPY per kW for up to 3.6 kW (maximum 360,000 JPY), 10,000 JPY per kW for over 3.6 kW. |
For the fiscal year 2026, pre-applications are being accepted from May 29 (will end once the budget is reached). From the pre-application for fiscal year 2026, submission of certificates issued by financial institutions will be 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). Must be installed between April 1, 2026, and March 30, 2031. If applying after October 1, 2026, only products registered with the national SII for fiscal year 2026 are eligible. | Battery storage package: 100,000 JPY per kWh (maximum 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 storage unit: 60,000 JPY per kWh (maximum 720,000 JPY per household). |
For the fiscal year 2026, pre-applications are being accepted from May 29. Grant application and performance reporting will start from June 30. |
| Setagaya Ward “Setagaya Eco Housing Subsidy for Fiscal Year 2026” | Individuals registered as residents in the ward who are renovating existing buildings within the ward using contractors from the ward (new homes are not eligible). Pre-registration before construction is required. Solar panels, stationary batteries, and solar thermal systems are not eligible. | Insulation renovations for windows and doors, installation of high-insulation bathtubs, high-reflective roof renovations, etc. (maximum 200,000 JPY). No subsidies for solar panels or batteries. | The first period (April 15 – August 31) has ended. The second period is from October 1, 2026, to January 31, 2027 (eligible construction is from September 1 to January 31, 2027). Updated on September 29, 2026. |
| National “DR Household Battery Storage Project” (Fiscal Year 2025 Supplement) | Newly introducing household battery storage 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 3/10, maximum 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 as stated on the official site, and applications are currently not possible). |
| National “Mirai Eco Housing 2026 Project” (Renovation) | Battery storage is one of the eligible facilities, but it must be combined with essential renovations such as insulation improvements for windows (openings) and the building structure; applications cannot be made for just battery installation. Solar panels are not included as eligible facilities. | Storage Battery: 96,000 JPY/unit | Ends once the budget limit is reached. As of October 5, 2026, the application amount for renovations is displayed as 8% of the budget on the official site. Please check the official site for the status of applications. |
The Tokyo solar power and storage battery subsidies require 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. In Setagaya Ward, the eco-home subsidy for fiscal year 2026 excludes solar panels and stationary storage batteries. Eligibility conditions, application procedures, and the possibility of combining different systems vary by program, and applying does not guarantee funding, so please confirm before contracting or starting work.
Kakeru Koumuten Co., Ltd. will provide guidance on eligibility conditions and application periods for each program after confirming them.
National Subsidy “DR Home Storage Battery Project (Support Project for Home Storage Systems for DR Resource Introduction)”
The national government has been implementing the “DR Home Storage Battery Project” to support the installation of home storage batteries.
This program targets those who are newly introducing registered storage systems that can be utilized for demand response (DR). 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 conditions such as that contracts or orders made before the grant decision are not eligible.
However, the fiscal year 2025 supplementary funding reached its budget on May 29, 2026, and the public offering has ended. The official site also states that there are no plans to reopen the public offering, and applications cannot be made at this time. Please check the official site for future public offerings.
Currently, there are 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 who are newly installing unused solar power generation systems in residential homes in Tokyo. The simultaneous installation of storage batteries is not a condition.
●Existing Homes: For systems below 3.75 kW, 150,000 JPY per kW (maximum 450,000 JPY); for systems over 3.75 kW and below 50 kW, 120,000 JPY per kW
●New Homes: For systems below 3.6 kW, 120,000 JPY per kW (maximum 360,000 JPY); for systems over 3.6 kW and below 50 kW, 100,000 JPY per kW
●Additional amounts are available for rooftop frame installation and waterproofing work.
The target is to install unused panels with an output of less than 50 kW that have obtained JET certification, for use in residential areas. The process involves prior application followed by a grant application after installation, and starting from the fiscal year 2026, submission of a certificate issued by a financial institution during the performance report is now mandatory.
The official page of Tokyo states that 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’s “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 yen per kWh (up to 1,200,000 yen per household)
●Additional for participating in DR demonstration: 100,000 yen per unit (150,000 yen per unit if energy management equipment is installed)
●Battery unit expansion: 60,000 yen per kWh (up to 720,000 yen per household)
The eligible applicants are owners of the subsidized equipment (excluding national and local governments), and the 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)
Setagaya Ward “Reiwa 8 Year Setagaya Ward Eco Housing Subsidy”
Setagaya Ward is implementing the “Setagaya Ward Eco Housing Subsidy” aimed at energy-saving renovations of homes within the ward. However, the official page of Setagaya Ward (updated September 29, Reiwa 8) states that solar panels, stationary batteries, and solar thermal systems are not eligible for subsidies in Reiwa 8.
●Eligibility: Individuals registered as residents in the ward who renovate existing buildings in the ward using contractors from the ward (newly built houses are not eligible)
●Eligible works: Insulation renovations for windows and doors, installation of high-insulation bathtubs, high-reflective roof renovations, etc.
●Maximum subsidy amount: 200,000 yen
Applications require pre-registration before construction, and the first period (April 15 – August 31) has already ended. The second period is from October 1, Reiwa 8 to January 31, Reiwa 9, and the eligible works are stated to be from September 1, Reiwa 8 to January 31, Reiwa 9. If you are considering solar panels or batteries, please check the Tokyo and national systems as they will be the main focus.
👉 Here is the official page of Setagaya Ward
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 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.
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, represented in kWh (kilowatt-hours).
The amount of kW that can be placed on the 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 panel costs as approximately 800,000 JPY to 1,200,000 JPY for 3-5 kW, and 1,200,000 JPY to 1,900,000 JPY for 6-10 kW. (These are rough estimates and can 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) 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 with a battery. |
| 3. Storage Battery | Manufacturer, model number, capacity (kWh), usable range during power outages (entire house or specific circuits), installation location. |
| 4. Mounting Frame & Fittings | Name of the fittings suitable for the roofing material and the method of securing them (whether it involves drilling holes or clamping). |
| 5. Wiring & Electrical Work | Wiring route and length, work around the distribution board, presence of a monitor to check power generation. |
| 6. Roof Reinforcement & Waterproofing | Details of waterproofing treatment at the fixing points, 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 roof work and exterior painting are done simultaneously, confirm that the same scope and quantity are not duplicated. |
| 9. Removal & 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 & Warranty | Whether prices are tax-inclusive or exclusive, conditions under which additional costs may arise, 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 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 get an approximate estimate and a profit simulation for up to 30 years!
If you know the total installation capacity of solar panels on the roof and the capacity of the storage battery, you can obtain an approximate estimate and profit simulation!
*The simulation results are approximate. Actual profits may vary based on assumptions such as electricity rates, self-consumption ratios, 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 Sales / Aluminum Catch Type Hardware |
| Fixing Method & Waterproofing Arrangement |
| Fixed to the horizontal metal roof using catch type hardware (Catch Method) |
| Price Range |
| 2,200,000 JPY～2,300,000 JPY *Due to the grant being provided, the actual burden amount is approximately 1,000,000 JPY Estimated recovery period for construction costs: about 8 to 9 years (self-consumption) *The grant amount and recovery 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 grants are available, and I would like to know how much can be provided. |
Our Proposal
We visited to provide an estimate and created a layout diagram for the solar panels from the drawings!
The layout diagram shows the arrangement of solar panels 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 Setagaya, Tokyo
There are many solar panel installation contractors available in Setagaya, Tokyo, and you may be unsure which one to choose.
Therefore, when requesting solar panel installation and battery storage installation work, let’s check the following 4 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 (3 companies is a guideline)
● Check if they provide support for subsidy applications
By confirming the above 4 points, you will be able to choose a reliable contractor.
Knowledge of 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 installed on a severely deteriorated roof causing leaks
・Solar panels installed on a roof with a short lifespan, requiring renovations for removal and reinstallation within a few years
・Misjudgment of the type of waterproofing leading to incorrect treatment and resulting in 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 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, 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 within the warranty period and conditions, they may cover the repairs under the warranty.
Additionally, some contractors provide aftercare services separate from warranties, so be sure to check if the contractor you are considering has aftercare services.
Since abnormalities or damages on the roof may not be visible, you might not notice them yourself.
By conducting inspections during aftercare, you can easily detect abnormalities early and prevent major repairs or failures!
At Kakeru Koumuten Co., Ltd., the installation of solar panels comes with a leak warranty as part of our workmanship warranty. (The warranty for solar panel installation is 10 years, and depending on the condition of the roof before installation, we may not be able to provide a warranty unless roof renovation is performed.)
We also provide aftercare maintenance, sending out annual direct mail!
After checking the DM, if you wish, we will visit for aftercare maintenance!
Get estimates from multiple contractors (3 companies is a guideline)
When requesting solar panel installation, let’s get estimates from multiple contractors.
Even for the same manufacturer and the same work content, costs may vary, and warranties and after-services may differ.
Additionally, obtaining multiple estimates makes it easier to negotiate prices.
To request from your desired contractor at a lower price, we recommend getting estimates from multiple contractors.
When comparing estimates, please check:
“Check the items in the estimate”
“Type of solar panel”
“Warranties and after-services”
and make a detailed comparison! Avoid judging solely based on cost, as lower costs can result from using lower-grade materials or skipping processes!
▶ To “Breakdown of installation capacity and equipment/construction costs” in this article
Check if they provide support for subsidy applications
There may be subsidies available for solar panel installation and battery installation, but if the order of procedures is incorrect or if there are deficiencies in the documents, the subsidy may not be granted.
Since there are systems like the Tokyo subsidy 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 the Tokyo subsidy, prior application) before proceeding with the construction!
For the Tokyo subsidy, after installation, a grant application and performance report must be submitted, and the flow will be granted after review! (The flow of procedures varies by system)
▶ To “Subsidies and grants that may be applicable in Setagaya, 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 generated electricity, 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 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 likely to be more advantageous to use it at home (self-consume) rather than sell it, making the combination with a storage battery a viable option.
👉 Ministry of the Environment, Trade and Industry | For purchase prices, periods, etc., 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 amount through subsidies is a significant advantage!
In Setagaya Ward, there is a possibility that the national and Tokyo Metropolitan systems may apply. The eco-house subsidy in Setagaya Ward does not cover solar panels or storage batteries for the 2026 fiscal year (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 may 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 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 deteriorating, it is reassuring to renovate it with durable roofing materials before installing solar panels!
Additionally, regular inspections of the equipment, repairs or replacements of the power conditioner, and costs for updating due to the deterioration of the storage battery will also be incurred.
It is reassuring to be able to request 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 brackets with screws to the roofing material or substrate, waterproofing of the fixed areas becomes crucial.
In methods that involve making holes in the roof, the risk of leaks inevitably arises.
Of course, we will 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 a catch method is also an option. (The catch method has compatibility conditions between the roofing material and brackets, and it cannot be used with all metal roofs.)
Catch-type base brackets exclusive to 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-bearing 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 by Total Output of the Roof
When installing solar panels on the roof, it is important to know how much electricity can be generated in a limited area, and generating more electricity is always better!
The size and output of solar panels vary by manufacturer.
A 350W output panel and a 400W output panel may seem that 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 a different number of panels that can be installed on the same roof due to the size difference.
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 one panel is lower, the total output of the roof may be higher!
It is important to consider the total output of the roof rather than the output of a single panel!
*The above is a calculation of total output (kW). The actual electricity generation amount (kWh) will vary depending on conditions such as the roof’s orientation, slope, and shading.
How to Choose 2: Compare by Degradation Rate of Solar Panels
Solar panels have a degradation rate, and their output gradually decreases over 10 years and 20 years.
The degree of output reduction after long-term use varies by product. The manufacturer’s output guarantee value is a standard figure for warranty purposes and does not indicate the actual degradation rate or electricity generation amount.
Choosing solar panels by considering the degradation rate, not just the initial output, will lead to a regret-free decision!
How to Choose 3: Compare by Warranty Period
There are several types of warranties for solar panels, including “output warranty,” “natural disaster warranty,” and “system warranty,” and the warranty periods vary by manufacturer.
For output warranties, some manufacturers offer a 30-year warranty, while others provide 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 Installation and Storage Battery Installation in Setagaya, Tokyo
We have compiled frequently asked questions from customers considering the installation of solar panels and storage batteries in Setagaya, Tokyo. (Tap to open answers)
How much does it cost to install solar panels and storage batteries in Setagaya, Tokyo?
The cost varies depending on the installation capacity, equipment, and roof condition. 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 by capacity are published on the solar panel installation 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 installations in Setagaya, Tokyo?
As of October 7, 2026, Tokyo’s “Household Solar Power Generation Promotion Project” (for existing homes, 15,000 yen per kW for up to 3.75 kW, with a maximum of 450,000 yen) and “Household Storage Battery Promotion Project” (100,000 yen per kWh, with a maximum of 1.2 million yen per household) are accepting pre-applications starting May 29, 2026, as listed on the official Tokyo (Cool Net Tokyo) page. Setagaya Ward has stated that solar panels and stationary storage batteries are not eligible for the Eco Housing Subsidy for the fiscal year 2026, as noted on Setagaya Ward’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?
This varies by program. Tokyo’s subsidies require pre-application. 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 differs by construction method, and when fixing brackets to the roofing material or substrate, waterproofing of the fixed parts is crucial.
Kakeru Koumuten is a specialized exterior renovation company strong in roofing work, so we will check the roof’s condition 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, renovating to a highly durable roofing material before installation may help reduce total costs.
Please consult us on how to proceed with the installation after checking the roof’s condition during the on-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 in your home rather than selling it.
Additionally, the Tokyo Metropolitan Government’s subsidy for storage batteries (for the Reiwa 8 fiscal year, it is 100,000 yen per kWh, with a maximum of 1,200,000 yen per household) aims to increase self-consumption of electricity generated by solar power. In Setagaya Ward, the eco-house subsidy for the Reiwa 8 fiscal year does not cover stationary storage batteries, so the Tokyo subsidy will be the main focus. You can compare “solar only” and “solar + storage battery” in the income and expenditure simulation for your consideration.
How many kW can be installed on our roof? Is it okay for north-facing roofs or roofs with shadows?
The capacity that can be installed varies depending on the shape, direction, and size of the roof. At Kakeru Koumuten, we create a layout diagram from the drawings and on-site survey, and we will provide you with the installation capacity and power generation simulation.
Setagaya Ward belongs to the Musashino Plateau, where the Kokubunji Cliff Line runs along the Tama River in the southern part, and the shape and direction of the roof, as well as the shading from surrounding buildings, vary for each house. You can check the expected power generation through the power generation simulation.
How long is the construction period?
For 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 there will be a separate period 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 (under 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, and the same price will apply 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 income and expenditure simulations that take into account loan interest rates and electricity rates.
Can you provide maintenance and inspections after installation?
Yes, we can. Kakeru Koumuten sends out annual after-maintenance DM notices and visits for inspections upon request from customers. We can also clean solar panels with a specialized brush if the power generation decreases due to dirt.
It is difficult to check areas on the roof by yourself, so 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 all in one go. The removed panels can be stored in our own warehouse.
For costs, please refer to the solar panel detachment and hot water heater removal pricing page.
If you are looking for a solar panel installation company in Setagaya, Tokyo, please consult Kakeru Koumuten Co., Ltd.
Our company handles a wide range of exterior renovations, including solar panels, roofing work, and exterior wall work in Setagaya, Tokyo.
We receive requests from many customers, including renovation companies and real estate agencies!
Kakeru Koumuten Co., Ltd. promises “high-quality renovations at low costs”, 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 is capable of performing all exterior renovations, not only roof overlay work and re-roofing but also partial roof repairs, exterior painting, and exterior cover installations.
We are also happy to assist with 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!
Whether you want to know about recommended solar panels, keep costs down, or just get an estimate, 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 shoes and will suggest the optimal construction plan!
We are confident that we will not be outdone in terms of cost, quality, and organization compared to other companies in 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!
Features of Setagaya, Tokyo, and Points for Solar Work
Setagaya Ward covers an area of approximately 58.05 square kilometers. It belongs to the Musashino Plateau of the Holocene strata, with a continuous cliff known as the Kokubunji Cliff Line along the Tama River flowing in the southern part of the ward, with an elevation of about 30 to 45 meters. We have summarized the characteristics of the terrain in Setagaya, Tokyo, and points to be careful about when installing solar panels and storage batteries below. (Tap to open)
View the features of Setagaya, Tokyo, and points for solar work
■ Terrain with cliffs and valleys. Check scaffolding, delivery, and shadows for each site
The official page of the ward introduces that small rivers flow through the area, forming valleys and low plains, and according to the land use survey for the fiscal year 2021, the average residential land area is 230.4 square meters, the building coverage ratio is 47.7%, and the average number of floors is 2.35. In sites with elevation differences, such as along cliff lines, or where the distance between neighboring houses is close, the space for scaffolding, the route for equipment delivery, and the shadow cast by neighboring houses vary from house to house. 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 this through a power generation simulation.
■ Check the hazard maps for Tama River floods, internal water flooding, and small river floods. Pay attention to the installation locations of equipment
Setagaya Ward has published hazard maps for floods and internal water flooding, including a version for Tama River floods and a version addressing small river floods and internal water flooding for rivers such as Nogawa and Sengawa, which was updated to the latest version in July of Reiwa 8. The impact of power conditioners and storage batteries, separate from the panels on the roof, may vary depending on where they are installed indoors or outdoors during water damage. Please check the expected flooding in your area using 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 and ages of roofs 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 lots vary from house to house. At Kakeru Koumuten, we will check the type and condition of the roof and the situation of the lot before installation and propose methods for securing the roof, waterproofing details, and scaffolding plans.
■ The annual sunshine hours at Tokyo Observatory is approximately 1,927 hours
According to the Japan Meteorological Agency’s average values (1991-2020), the annual sunshine hours at Tokyo Observatory is approximately 1,927 hours, with January (approximately 193 hours) having the most, and June during the rainy season (approximately 124 hours) having the least. (This is not based on observation values within Setagaya Ward, but is a reference value.)
The power generation in Setagaya 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 to match the times of high electricity usage are key points.
Our company handles many exterior construction and solar power projects in Setagaya 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 Setagaya Ward, Tokyo
Kakeru Koumuten accepts requests throughout Kanagawa Prefecture and all of Tokyo.
List of Areas in Setagaya Ward, Tokyo
Setagaya Ward, Akatsuki / Setagaya Ward, Ikejiri / Setagaya Ward, Unanene / Setagaya Ward, Umegaoka / Setagaya Ward, Okura / Setagaya Ward, Ohara / Setagaya Ward, Okamoto / Setagaya Ward, Okusawa / Setagaya Ward, Oyamadai / Setagaya Ward, Kasuya / Setagaya Ward, Kamata / Setagaya Ward, Kamiyama / Setagaya Ward, Kamikitazawa / Setagaya Ward, Kamisoshigaya / Setagaya Ward, Kaminoge / Setagaya Ward, Kamiyoga / Setagaya Ward, Kitakusuyama / Setagaya Ward, Kitazawa / Setagaya Ward, Kitami / Setagaya Ward, Kinuta / Setagaya Ward, Kinuta Park / Setagaya Ward, Kyuden / Setagaya Ward, Kyodo / Setagaya Ward, Gotokuji / Setagaya Ward, Komazawa / Setagaya Ward, Komazawa Park / Setagaya Ward, Sakura / Setagaya Ward, Sakuragaoka / Setagaya Ward, Sakurashinmachi / Setagaya Ward, Sakurajōsui / Setagaya Ward, Sangenjaya / Setagaya Ward, Shimoma / Setagaya Ward, Shinmachi / Setagaya Ward, Seijo / Setagaya Ward, Seta / Setagaya Ward, Setagaya / Setagaya Ward, Soshigaya / Setagaya Ward, Taishido / Setagaya Ward, Daisawa / Setagaya Ward, Daita / Setagaya Ward, Tamagawa / Setagaya Ward, Tamagawadai / Setagaya Ward, Tamagawa Denenchofu / Setagaya Ward, Tamazutsumi / Setagaya Ward, Chitosedai / Setagaya Ward, Tsurumaki / Setagaya Ward, Todoroki / Setagaya Ward, Nakacho / Setagaya Ward, Noge / Setagaya Ward, Nozawa / Setagaya Ward, Hachiman-yama / Setagaya Ward, Hanegi / Setagaya Ward, Higashitamagawa / Setagaya Ward, Fukazawa / Setagaya Ward, Funabashi / Setagaya Ward, Matsubara / Setagaya Ward, Mishuku / Setagaya Ward, Minami-Karasuyama / Setagaya Ward, Miyasaka / Setagaya Ward, Yoga / Setagaya Ward, Wakabayashi
・Leave your exterior wall painting in Setagaya, Tokyo to Kakeru Koumuten!
・Leave your roof renovation in Setagaya, Tokyo to Kakeru Koumuten!
・Leave your exterior renovation in Setagaya, Tokyo to Kakeru Koumuten!
・Kakeru Koumuten Co., Ltd. construction achievements
・Kakeru Koumuten Co., Ltd. after maintenance
・Kakeru Koumuten Co., Ltd. construction menu and price list
・Kakeru Koumuten Co., Ltd. staff blog and announcements
・Explaining the importance of comparative estimates and key points!
・Top 12 solar power generation manufacturers! Features and selection tips included!
・What are the installation costs for solar power generation? Thorough explanation of cost-saving tips!
・What are the best locations for solar power installation? Key points for site selection included!
・Here is the introduction to solar power generation estimates!
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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!
