Leave Your Solar Panel Installation in Setagaya, Tokyo to Kakeru Koumuten Co., Ltd.!
For solar panel and battery installation in
Setagaya, Tokyo,
Kakeru Koumuten is at your service!
Kakeru Koumuten is a company specializing in exterior renovations.
As a strong player in roofing, we are entrusted withsolar panel and battery installation considering roofing and waterproofing!
“How to Choose a Solar Panel Contractor in Setagaya, Tokyo”
“Costs for Solar Panel and 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 have no regrets about your solar panel installation, we recommend obtainingcomparative estimates from about three companies!
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 Installation Company 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 Installation Company in Setagaya, Tokyo, Contact Kakeru Koumuten
- Characteristics of Setagaya, Tokyo and Points for Solar Construction
- Service Area in Setagaya, Tokyo
Reasons Why Kakeru Koumuten is Chosen for Solar Panel Installation in Setagaya, Tokyo
Regarding the reasons why we are entrusted with solar panel installation by customers in Setagaya, 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 be grateful 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 Besides Solar Panel Installation!
Problems such as leaks that occur with solar panel installation may be caused by insufficient verification of the roof and waterproofing at the installation site.
Even if one is knowledgeable about solar panels, there are cases where the roof and waterproofing at the installation site are outside their expertise, so caution is necessary.
It is reassuring to have expertise in roofing to avoid maintenance issues and troubles after installation!
Kakeru Koumuten Co., Ltd. is strong in roofing work and can also detach and attach solar panels in-house, allowing for quick responses to maintenance and urgent troubles after solar panel installation!
2.Facilities Specialized in Exterior Renovation
Kakeru Koumuten Co., Ltd. has prepared the following warehouses and material storage areas to provide low-cost, high-quality solar work and exterior renovations.
We have established five bases for material storage and showrooms.
In-house Ownership of Scaffolding Materials
To ensure safety during work on the roof, we own the scaffolding materials necessary for temporary scaffolding according to construction conditions and can assemble scaffolding in-house.
By performing scaffolding work with our own scaffolding team instead of outsourcing, we can also cut costs for scaffolding work.
We own scaffolding materials for approximately 50 single-family homes!
Even if there are height differences on the site, our in-house scaffolding team will plan the scaffolding according to the local conditions.
Storage of Materials in Our Large Warehouse
We store roofing materials and paints, and we can also store removed solar panels.
By ordering a large quantity of materials at once, you canpurchase materials at a lower cost!
Additionally, we always have a stock of roofing materials, allowing us torespond quickly in emergencies!
Sorting and Transporting Waste Materials In-House
The installation of solar panels often involves roofing work, generating various waste materials such as 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 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 explain the structure, allowing for detailed explanations!
3.All Work Performed by Our Own Team
One of Kakeru Koumuten’s major strengths is its complete in-house construction.
By having a consistent system from inquiry to project completion, Kakeru Koumuten can keep costs down while providing high-quality roof renovations.
Additionally, one representative will handle everything from the estimate to project completion.
Since the担当者, such as sales and construction management, do not change, 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 workers and painting technicians, and we are confident in our construction techniques.
We can also handle large-scale roof construction for factories and other buildings!
5. Warranty and Aftercare
In addition to the manufacturer’s warranty for solar panel installation, we also provide our own施工保証 (leak warranty)!
(The施工保証 for solar panel installation is 10 years. Depending on the condition of the roof before installation, we may not be able to provide a warranty unless roof renovations are performed. The施工保証 is separate from the manufacturer’s product warranty, and the scope and conditions vary based on the warranty content.)
Aftercare is available annually, and we send out notification DM every year.
If you have questions about the warranty, please click on the image above!
6. Flexible and Prompt Response
Our company is equipped to handle various roofing troubles and situations.
If you cannot access the roof at high altitudes, we can utilize a drone to assist!
During leak investigations, we can also conduct inspections using a thermal imaging camera.
In cases where the power generation of solar panels decreases due to dirt, we can perform cleaning using specialized brushes.
We will respond according to the customer’s wishes.
7. Human Resource Development
We create various roof models for skill enhancement 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 each staff member can handle various cases.
8. Creation of Easy-to-Understand Materials and Simulations
Kakeru Koumuten provides not only “estimates,” “layout diagrams,” and “power generation simulations” but also a “solar installation guidebook” and a “profit and loss simulation” that considers 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.
For customers who are not familiar with solar installations, we compile easy-to-understand materials that include points to note and disadvantages!
We encourage you to obtain comparative estimates and compare them with other companies’ plans!
Roof Inspection Before Installing Solar Panels
Once solar panels are installed, they will remain on the roof for 20 or 30 years.
Confirming “Is it okay to install them directly on the current roof?” before installation is the key point to prevent leaks and unnecessary expenses!
Kakeru Koumuten, which specializes in roofing work, has summarized the items to check before installation.
| 1. Types of Roofing Materials and Age | The fixing method varies depending on the roofing material, such as slate, tiles, metal roofs, and flat roofs (rooftop waterproofing). If the remaining lifespan of the roofing material is short, we may suggest roof renovation first. |
| 2. Condition of Substrate and Waterproof Sheet | If the sheathing or roofing (waterproof sheet) beneath the roofing material is damaged, it will affect the fastening strength and waterproofing. We will also check for any signs of leaks. |
| 3. Orientation, Slope, and Shadows of the Roof | The orientation and slope of the roof surface, as well as shadows from neighboring houses, trees, and utility poles, will affect the power generation. We will create a layout diagram from the drawings and the site, and you can check 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 fastening or using brackets to secure the roofing material. The fixing method varies by technique, so please check the waterproofing treatment method for the fixing parts during the estimate. |
| 6. Weight of the Roof | The roof will become heavier due to the panels being installed. After investigating the existing roof, substrate, and load-bearing capacity, switching to lighter roofing materials may also be an option if necessary. |
| 7. Installation Location of Equipment and Wiring | We will check the installation location of the power conditioner and storage battery, as well as the wiring route to the distribution board. The length of the wiring will also affect the cost. |
| 8. Ease of Scaffolding Setup and Delivery Routes | If there are elevation differences on the site, planning for scaffolding and the delivery routes for equipment and materials may require some ingenuity. The width of the front road and the elevation differences on the site will also be checked during the site survey. |
Fixing Methods and Checkpoints by Roofing Material
| Roof Material | Main Fixing Method | Pre-Installation Check Points |
|---|---|---|
| Slate Roof | Varies by method (e.g., fixing brackets to the roof material and substrate with screws) | Waterproof treatment of fixing parts, cracks or deterioration of slate, condition of the substrate. If deterioration is advanced, consider roof overlay (cover method) or replacement first. |
| Tile Roof | Fixed with brackets and methods suitable for the type of tile (even methods that do not drill holes in the tiles will fix to the substrate) | Type and condition of tiles, substrate, load-bearing capacity. Depending on the investigation results, there may be a method to replace with lighter roofing material before installation. |
| Metal Roof (Horizontal and Vertical) | Fixed with catch-type brackets that grip the roof material (depends on the combination of roof material and brackets) | Whether the roof material and brackets are compatible, installation conditions from the roof material manufacturer. If compatible, a method that does not drill holes may be selectable. |
| Flat Roof / Rooftop | Fixed by installing a frame | Type and deterioration status of the waterproof layer, waterproofing around the frame. Consider in conjunction with the timing of waterproofing work. |
If you perform roof renovation 10 to 20 years after installation, there will be additional costs for removing and reinstalling solar panels. If the roof is deteriorating, it may be more cost-effective in the long run to renovate to a highly durable roofing material before installation.
Kakeru Koumuten is strong 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 renovation in Setagaya, Tokyo
PossibleSubsidies and Grants in Setagaya, Tokyo
If you introduce solar panels or storage batteries in Setagaya, Tokyo, there is a possibility that “national” and “Tokyo” systems may apply. In Setagaya, the eco-house subsidy for Reiwa 8 does not cover solar panels or storage batteries.
The following is based on the information checked on the official pages of each system as of October 7, 2026. The acceptance status may change depending on the budget, so please check the latest information before contracting or starting work.
Eligibility Conditions and Application Timing for Subsidy Programs
| Program | Main Eligibility Conditions | Subsidy Amount | Application Period & Status |
|---|---|---|---|
| Tokyo “Home Solar Power Generation Promotion Project” | Individuals, corporations, or management associations installing a new unused solar power system (output under 50kW, JET certification, etc.) in residential properties within Tokyo. The generated power must be used in the residential part. Pre-application is required. | Existing homes: 15,000 JPY per kW for up to 3.75 kW (maximum 450,000 JPY), 12,000 JPY/kW for over 3.75 kW to under 50 kW. New homes: 12,000 JPY/kW for up to 3.6 kW (maximum 360,000 JPY), 10,000 JPY/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 “Home Battery Installation Promotion Project” | Owners of eligible equipment (batteries registered with SII) excluding national and local governments. Installation must occur between April 1, 2026, and March 30, 2027.If applying after October 1, 2026, only products registered with the national SII for fiscal year 2026 are eligible. | Battery 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 units: 60,000 JPY/kWh (maximum 720,000 JPY per household). |
For the fiscal year 2026, pre-applications are being accepted from May 29. Grant applications and performance reports will be accepted from June 30. |
| Setagaya Ward “Fiscal Year 2026 Setagaya Eco Housing Subsidy” | Individuals registered as residents in the ward who are renovating existing buildings in the ward with 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-efficiency bathtubs, and high-reflective roof renovations are eligible (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 Home Battery Project” (Fiscal Year 2025 Supplement) | Newly introducing home 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 maximum 600,000 JPY per application). | The budget was reached on May 29, 2026, and the public offering has ended (the official site states there are no plans to reopen the public offering, and applications cannot be made at this time). |
| National “Mirai Eco Housing 2026 Project” (Renovation) | Batteries are one of the eligible facilities, but they must be combined with essential renovations such as insulation for windows (openings) and the building structure; applications cannot be made for battery installation alone. Solar panels are not included as eligible facilities. | Battery: 96,000 JPY per household. | Budget will end as soon as the limit is reached. As of October 5, 2026, the application amount for renovations is displayed as 8% of the budget on the official website. Please check the reception status on the official site. |
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 simultaneous applications vary by program, and applying does not guarantee issuance, so please confirm before contracting or starting work.
Kakeru Koumuten will provide guidance on eligibility conditions and application periods for each program after confirming them.
National Subsidy “DR Home Storage Battery Project (Support Project for the Introduction of Home Storage Systems for DR Resource Implementation)”
The government has been implementing the “DR Home Storage Battery Project” to support the installation of home storage batteries.
This program targets those who are introducing new storage systems of registered products that can be utilized for demand response (DR). In the fiscal year 2025 supplementary project, the subsidy amount was determined based on a standard amount of 34,500 JPY per 1 kWh of initial effective capacity, 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 application amount reached the budget on May 29, 2026, and the public offering has ended. The official site also states that there are no plans to resume the public offering, and applications are currently not possible. Please check the official site for future public offerings.
Additionally, there are currently no subsidies confirmed for the installation of solar panels on existing homes.
👉 Here is the official site for the DR Home Storage Battery Project
Tokyo “Promotion Project for the Introduction of Solar Power Generation in Homes”
This subsidy is for those who are installing unused solar power generation systems in residential homes in Tokyo. The simultaneous installation of storage batteries is not a condition.
● Existing homes: For systems under 3.75 kW, 150,000 JPY per kW (maximum 450,000 JPY); for systems over 3.75 kW and under 50 kW, 120,000 JPY per kW.
● New homes: For systems under 3.6 kW, 120,000 JPY per kW (maximum 360,000 JPY); for systems over 3.6 kW and under 50 kW, 100,000 JPY per kW.
● Additional amounts for rooftop frame installation and waterproofing work are also available.
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 from the fiscal year 2026, submission of a certificate issued by a financial institution is mandatory at the time of performance reporting.
The official page of Tokyo states that prior applications have been accepted since May 29, 2026. The program will end as soon as the budget is reached, so please check the official page for the reception status.
👉 Here is the official page of Tokyo (Cool Net Tokyo)
Tokyo’s “Home 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)
●Battery unit expansion: 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, 2026, and March 30, 2027. If applying in advance after October 1, 2026, only products registered in the national SII for the fiscal year 2026 will be eligible.
The official Tokyo page states that advance applications have been accepted since May 29, 2026. For detailed information, including conditions for combining with solar power generation, please check the official page.
👉 Click here for the official Tokyo (Cool Net Tokyo) page
Setagaya Ward “Fiscal Year 2026 Setagaya Eco Housing Subsidy”
Setagaya Ward is implementing the “Setagaya Eco Housing Subsidy” aimed at energy-saving renovations of homes within the ward. However, the official Setagaya Ward page (updated September 29, 2026) states that solar panels, stationary batteries, and solar thermal systems are not eligible for subsidies in fiscal year 2026.
●Eligibility: Individuals registered as residents in the ward who renovate existing buildings in the ward with 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 JPY
Applications require prior registration before construction, and the first period (April 15 – August 31) has ended. The second period is from October 1, 2026, to January 31, 2027, with eligible works from September 1, 2026, to January 31, 2027. If you are considering solar panels or batteries, please check the Tokyo and national systems as they will be the main focus, so refer to the above Tokyo system.
👉 Click here for the official Setagaya Ward page
Solar Panel Installation & Battery Installation Price List
⇧Service Menu | For costs related to solar panel removal and water heater removal, click here
Breakdown of Installation Capacity, Equipment, and Construction Costs
The costs for solar panels and storage batteries should be confirmed by separating them into “Equipment Costs (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 Storage Battery Capacity (kWh)
The installation capacity of solar panels is determined by “Output of One Panel (W) × Number of Panels”, with the unit being kW (kilowatts). Storage 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 the roof varies for each house depending 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 JPY to 1,200,000 JPY for 3 to 5 kW, and 1,200,000 JPY to 1,900,000 JPY for 6 to 10 kW. (These are just estimated amounts and may vary based on factors such as wiring length, scaffold range, existing roofing materials, and panel layout.)
▶ Installation Menu | Costs for Solar Panel Installation and Battery Installation
Items to Confirm in the Estimate (Cost Check)
When comparing estimates, it is common to compare different capacities and equipment based solely on price. 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) are written. |
| 2. Power Conditioner | Manufacturer, model number, capacity, number of units, installation location (indoor/outdoor). Also confirm whether it is a type that controls in conjunction with the battery. |
| 3. Battery | Manufacturer, model number, capacity (kWh), range usable during a power outage (entire house or specific circuits), installation location. |
| 4. Mounting Frame and Hardware | Name of hardware suitable for roofing materials and method of securing (whether it is a method that drills holes or a method that clamps to secure). |
| 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 application for selling electricity (FIT), and subsidy applications. |
| 8. Scaffolding | Range and quantity of scaffolding. If it is simultaneous with roofing work or exterior painting, check that the same range and quantity are not double counted. |
| 9. Removal and Disposal | Whether the removal of existing solar thermal water heaters or old panels and disposal costs for waste materials are included. |
| 10. Tax Classification and Warranty | Whether it is tax-inclusive or tax-exclusive, conditions under which additional costs may arise, and details and duration of manufacturer and workmanship warranties. |
If the capacities differ, both the price and power generation will change. Kakeru Koumuten Co., Ltd. welcome 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 estimated quote and a financial 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 estimated quote and financial simulation!
*The simulation results are estimates. Actual financial results may vary based on assumptions such as electricity rates, self-consumption ratios, feed-in prices, and costs for equipment inspection and replacement.
Customer Feedback
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customer reviews
Asao-ku, Kawasaki City | We received reviews about the ridge cap and rain gutter replacement work!
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customer reviews
Kohoku-ku, Yokohama | We received reviews about the roof overlay (cover method)!
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customer reviews
Kohoku-ku, Yokohama | We Received Reviews About Exterior Painting!
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customer reviews
Hodogaya-ku, Yokohama | We received reviews about our exterior fence construction!
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customer reviews
Tsurumi-ku, Yokohama | We received reviews about roof and exterior wall painting, as well as metalwork and rain gutter replacement work!
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customer reviews
Higashiyamato City, Tokyo | We received reviews about exterior painting and roof overlay (cover method)!
Case Studies of Solar Panel Installations
| Construction Details |
| Solar Panel Installation Battery Installation |
| Existing Roofing Material |
| Horizontal Metal Roof (Super Galtect) |
| Installation Capacity |
| Solar Panel: 4.3kW Battery: 5kWh |
| Base Mounting Hardware Used |
| Niigata Manufacturing/Aluminum Catch Type Hardware |
| Fixing Method & Waterproofing Details |
| Fixed using catch type hardware to grip the horizontal metal roof (Catch Method) |
| Price Range |
| 2,200,000 JPY～2,300,000 JPY *Due to the grant being provided, the actual burden amount is approximately 1,000,000 JPY Estimated recovery period for construction costs: about 8 to 9 years (self-consumption) *The grant amount and recovery 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 introduction of solar panels and storage batteries. I heard that grants are available, and I would like to know how much will be provided. |
Our Proposal
We visited to provide an estimate and created a layout diagram for the solar panels from the drawings!
The layout diagram shows the arrangement when solar panels are 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 Setagaya, Tokyo
There are many solar panel installation contractors that serve Setagaya Ward, Tokyo, and you may be unsure which contractor to choose.
Therefore, when requesting solar panel installation and battery storage installation work, let’s check the following four points.
● Have extensive knowledge not only about solar panels but also about roofs
● Confirm the existence of warranties and aftercare services
● Obtain estimates from multiple contractors (three companies is 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.
Have knowledge not only about solar panels but also about roofs
Defective installation of solar panels can sometimes be caused by a lack of knowledge and confirmation 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 confirmation of roofs and waterproofing
・Solar panels were installed on a deteriorated roof, leading to leaks
・Solar panels were installed on a roof with a short lifespan, necessitating a remodel to detach and reattach the solar panels within a few years
・Misjudgment of the type of waterproofing led to incorrect treatment and subsequent leaks
and more
When installing solar panels, understanding the condition and type of the existing roof allows you to avoid unnecessary expenses and unexpected troubles.
▶ Go to “Roof Confirmation Before Installing Solar Panels” in this article
Confirm the existence of warranties and aftercare services
When choosing a solar installation contractor, let’s confirm the existence of warranties. It is important to check not only the duration of the warranty but also the scope of coverage, disclaimers, and cost conditions.
Solar panels and battery storage units come with manufacturer warranties, but also check for the existence of installation warranties in case leaks occur after installation!
For contractors that offer installation warranties, 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 make sure to check if the contractor you are considering has aftercare services.
Since abnormalities or damage on the roof can be in unseen areas, you may not notice them yourself.
By conducting inspections of unseen areas during aftercare maintenance, you can more easily detect abnormalities early and prevent major repairs or failures!
Kakeru Koumuten Co., Ltd. provides a rain leak guarantee 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, we may not be able to provide a warranty unless roof renovations are performed.)
We also conduct aftercare maintenance and send out annual DM!
After confirming the DM, we will visit for aftercare maintenance if you wish!
Obtain estimates from multiple contractors (3 companies as a guideline)
When requesting solar panel installation, let’s obtain estimates from multiple contractors.
Even for the same manufacturer and the same construction content, costs may vary, and warranties and after-sales services may differ.
Additionally, obtaining multiple estimates makes it easier to negotiate prices.
To request your desired contractor at a lower price, we recommend obtaining estimates from multiple contractors.
When comparing estimates, please check:
“Confirmation of estimate items”
“Types of solar panels”
“Warranties and after-sales services”
and make a detailed comparison for your judgment! Avoid judging solely based on cost, as using lower-grade materials or skipping processes can reduce costs!
▶ Go to “Breakdown of installation capacity, equipment, and construction costs” in this article
Check if they provide support for subsidy applications
There may be subsidies available for solar panel installations and battery installations, but if the order of procedures is incorrect or there are deficiencies in the documents, the subsidy may not be granted.
Since there are systems like 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 is required) before proceeding with the construction!
For the Tokyo subsidy, after installation, you will need to submit a grant application and performance report, which will be reviewed before the grant is provided! (The flow of procedures varies by system)
▶ Go 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 the following 5 points!
Benefit 1: Economic Benefits
The biggest advantage of introducing solar panels is the economic benefit!
The selling price of electricity has decreased compared to ten years ago, but by consuming the electricity generated, you can reduce the amount of electricity purchased from the utility company and gain benefits!
As electricity 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 (under 10kW) will be set as “24 yen/kWh for the first four years, and 8.3 yen/kWh from the fifth to the tenth year” for certifications after October 2025, and the same price will apply for the fiscal year 2026. After the fifth year, it is likely to be more advantageous to use it at home (self-consumption) rather than selling it, so combining it with a storage battery is also an option.
👉 For purchase prices, periods, etc., visit the Agency for Natural Resources and Energy
Advantage 2 Subsidies can be utilized!
The conditions and amounts of subsidies vary by prefecture and municipality, but if you meet the conditions, you may be able to utilize subsidies!
Reducing the actual burden through subsidies is a significant advantage!
In Setagaya Ward, there is a possibility of being eligible for national and Tokyo Metropolitan programs. The eco-housing subsidy in Setagaya Ward does not cover solar panels and storage batteries for the fiscal year Reiwa 8 (please check the application status for each program).
Advantage 3 Environmentally friendly!
Solar power generation has low carbon dioxide emissions and can reduce dependence on fossil fuels, contributing to the mitigation of global warming.
Solar panels themselves do not produce noise or exhaust gases during the generation process, making them an environmentally friendly method of power generation. (However, devices like power conditioners do have operational noise.)
Advantage 4 Heat insulation effects are expected!!
By installing them on the roof or rooftop, the panels block direct sunlight to the roof.
Especially in summer, it can help reduce the temperature of the roof, providing expected heat insulation effects!
（This does not improve the insulation performance of the building itself）
Benefit 5 Electricity can be used even during power outages!!
If a storage battery is installed, it 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 capability, 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 remodeling 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 remodel it with durable roofing materials before installing solar panels!
Additionally, there will be costs for regular inspections of the equipment, repairs or replacements of the power conditioner, and updates due to the deterioration of the storage battery.
It would be reassuring to ask for a simulation considering 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 in methods that fix hardware to the roofing material and substrate with screws, waterproofing of the fixed parts becomes crucial.
In methods that involve making holes in the roof, the risk of leaks inevitably arises.
Of course, we will ensure proper waterproofing, but if you are concerned about making holes, replacing the roofing material with a metal roof and fixing the solar panels using the catch method is also an option. (The catch method has compatibility conditions between the roofing material and hardware, and it cannot be used with all metal roofs)
Catch-type base metal fittings for horizontal metal roofs
Note 3: The roof will become heavier
Since solar panels will be installed, the roof will become heavier. After investigating the existing roof, substrate, and load capacity, replacing it with a lighter roof may also be an option if necessary.
How to Choose Solar Panels?
There are many manufacturers of solar panels, and their output and costs vary.
It is not simply a matter of “this manufacturer has the best solar panels”; it is important to choose solar panels that are suitable for your life plan and building!
Here are some points to consider when comparing solar panels!
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 the more electricity generated, the better!
Solar panels come in various sizes and outputs depending on the manufacturer.
A panel with an output of 350W and a panel with an output of 400W may seem that the higher output panel is better at first glance.
However, if the size of the panel does not fit well with the roof, “20 panels of 350W can be installed, while only 15 panels of 400W can be installed,” meaning that the number of panels that can be installed may differ even 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 (kWh) will vary depending on conditions such as roof 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 or 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.
Choosing solar panels while considering the degradation rate, rather than just the initial output, will help you avoid regrets!
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!
It’s always better to have a longer warranty, so let’s check the warranty periods and conditions of the manufacturers you are considering!
Frequently Asked Questions about Solar Power 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 the 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 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 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 power and storage battery installation in Setagaya, Tokyo?
As of October 7, 2026, Tokyo’s “Solar Power Introduction Promotion Project for Households” (for existing homes, 15,000 yen per kW for up to 3.75 kW, with a maximum of 450,000 yen) and “Storage Battery Introduction Promotion Project for Households” (100,000 yen per kWh, with a maximum of 1.2 million yen per household) are accepting pre-applications starting May 29, 2026, as stated on the official page of Tokyo (Cool Net Tokyo). In Setagaya, it is noted on the official page that solar panels and stationary storage batteries are not eligible for the Eco Housing Subsidy for the 2026 fiscal year. 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 depends on the system. Tokyo’s subsidies require prior application. Conditions such as whether you can contract and start construction before applying differ by system, so please check before signing a contract.
The order of procedures varies by system, so please confirm before contracting and 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 fixing method varies by construction method, and when fixing brackets to the roofing material or substrate, waterproofing treatment of the fixed parts is essential.
Kakeru Koumuten is a specialized exterior renovation company strong in roofing work, so we will check the condition of the roof before installation and if deterioration is progressing, we can also propose methods such as roof overlay (cover method) or replacement before installation.
My roof is old. Should I do a roof renovation first?
It depends on the condition of the roof. If a roof renovation is needed after 10 to 20 years, there will be an additional cost for removing and reinstalling solar panels. If the remaining lifespan of the roof is short, it may be more cost-effective to renovate with durable roofing materials before installation.
Please consult us on how to proceed with the installation after confirming the condition of the roof through a site survey!
Is it better to install a storage battery together with the solar panels?
For those who want to use the generated electricity at night or prepare for power outages, simultaneous installation is recommended. The selling price for electricity 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 Reiwa 8, it is 100,000 yen per kWh, with a maximum of 1.2 million yen per household) aims to increase self-consumption of electricity generated by solar power. In Setagaya Ward, the eco-house subsidy for Reiwa 8 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 a financial simulation for your consideration.
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 blueprints and site survey, and 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 orientation 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 will the construction period be?
In the above construction example (solar panels 4.3 kW + storage battery), it took about 3 days. The duration may vary depending on whether roof work is done simultaneously and the shape and installation capacity of the roof.
Please note that there will be an additional period for applying for subsidies and to the power company, so please consult us early.
What is the current selling price (FIT)?
For residential use (less than 10 kW), from the certification after October 2025, the first 4 years will be 24 yen/kWh, and from the 5th to the 10th year, it will be 8.3 yen/kWh, and the same price will apply for the 2026 fiscal year.
The idea is to recover the 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 costs.
Can you handle maintenance and inspections after installation?
Yes, we can. Kakeru Koumuten sends out annual after-maintenance DM notifications and visits for inspections upon request from customers. We can also clean solar panels with a dedicated brush if the power generation is reduced 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 remove and reinstall 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 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 contractor in Setagaya, Tokyo, please consult Kakeru Koumuten
Our company handles a wide range of exterior renovations, including solar panels, roof work, and exterior wall work in Setagaya, Tokyo.
We have received requests from many customers, including renovation companies and real estate agencies!
Kakeru Koumuten promises “high-quality renovations at low costs”, and we have received positive feedback from numerous customers.
We continue to update our construction performance records every year, and we 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 methods for exterior walls.
We are happy to handle small jobs such as 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 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 the customer’s position and will propose the best construction plan!
We are confident that we will not be outdone by other companies in terms of cost, quality, and efficiency in exterior work!
We welcome competitive quotes because we are confident!
Estimates are completely free, and if our company is inferior to others, feel free to decline!
Characteristics of Setagaya, Tokyo and Key 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, and along the Tamagawa River flowing through the southern part of the ward, there is a continuous cliff known as the Kokubunji Cliff Line, with an elevation of about 30 to 45 meters. We have summarized the characteristics of the terrain in Setagaya, Tokyo, and key points to consider when installing solar panels and storage batteries below. (Tap to open)
View the characteristics of Setagaya, Tokyo and key 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 in the land use survey for the fiscal year 2021, it is reported that 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 to neighboring houses is close, the space for scaffolding, the route for equipment delivery, and the impact of shadows from 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 blueprints and site surveys, and you can confirm this through a power generation simulation.
■ Check the hazard maps for Tamagawa floods, internal water flooding, and small river floods. Pay attention to the installation location of equipment
Setagaya Ward has published hazard maps for floods and internal water flooding, including a version for Tamagawa floods and a version that addresses small river floods and internal water flooding such as Nogawa and Sengawa, which was updated to the latest version in July of Reiwa 8 . The impact of flooding may vary depending on where power conditioners and storage batteries are installed, whether indoors or outdoors, separate from the panels on the roof. Please check the flooding assumptions for your residence on the ward’s hazard map and consult with us about the installation location and height in accordance with the installation conditions of the manufacturer you will use.
■ 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 the Tokyo Observatory are about 1,927 hours
According to the Japan Meteorological Agency’s average values (1991-2020), the annual sunshine hours at the Tokyo Observatory are about 1,927 hours, with January (about 193 hours) having the most and June during the rainy season (about 124 hours) having the least. (This is a reference value, not an observation value within Setagaya Ward.)
The power generation in Setagaya Ward can also be affected by shadows from surrounding buildings, so it is important to conduct a year-round power generation simulation and choose the capacity of the storage battery according to the time periods when electricity is used the most.
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, Umegau / Setagaya Ward, Okura / Setagaya Ward, Ohara / Setagaya Ward, Okamoto / Setagaya Ward, Okusawa / Setagaya Ward, Ooyama / Setagaya Ward, Kasuya / Setagaya Ward, Kamata / Setagaya Ward, Kamiyama / Setagaya Ward, Kamikitazawa / Setagaya Ward, Kamisoshigaya / Setagaya Ward, Kaminoge / Setagaya Ward, Kamiyouga / Setagaya Ward, Kitakusuyama / Setagaya Ward, Kitazawa / Setagaya Ward, Kitami / Setagaya Ward, Kinuta / Setagaya Ward, Kinuta Park / Setagaya Ward, Kyuden / Setagaya Ward, Kyoudou / Setagaya Ward, Goutokuji / Setagaya Ward, Komazawa / Setagaya Ward, Komazawa Park / Setagaya Ward, Sakura / Setagaya Ward, Sakuragaoka / Setagaya Ward, Sakurashinmachi / Setagaya Ward, Sakurajousui / 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, Tamagawadenenchoufu / 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, Minamikusuyama / Setagaya Ward, Miyasaka / Setagaya Ward, Youga / Setagaya Ward, Wakabayashi
・For exterior wall painting in Setagaya, Tokyo, trust Kakeru Koumuten Co., Ltd.!
・For roof renovations in Setagaya, Tokyo, trust Kakeru Koumuten Co., Ltd.!
・For exterior renovations in Setagaya, Tokyo, trust Kakeru Koumuten Co., Ltd.!
・Kakeru Koumuten Co., Ltd. project achievements
・Kakeru Koumuten Co., Ltd. aftercare services
・Kakeru Koumuten Co., Ltd. service menu and price list
・Kakeru Koumuten Co., Ltd. staff blog and announcements
・Explaining the importance of getting multiple estimates and points to compare!
・Top 12 solar power manufacturers! Features and selection tips included!
・What are the installation costs for solar power? Comprehensive tips to reduce costs!
・What are the best locations for solar power installation? Points for selecting installation sites included!
・Check out our solar power installation 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!
