Leave Your Solar Panel Installation Work in Shinagawa, Tokyo to Kakeru Koumuten Co., Ltd.!
For solar panel and storage battery installation in
Shinagawa, Tokyo,
trust Kakeru Koumuten!
Kakeru Koumuten is a company specializing in exterior renovations.
As a company strong in roofing work, we are entrusted withsolar panel and storage battery installations considering roofing and waterproofing!
“How to Choose a Solar Panel Contractor in Shinagawa, Tokyo”
“Costs for Solar Panel and Storage Battery Installation”
“Subsidies Available for Solar System Installation in Shinagawa, 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 obtainingthree estimates!
Table of Contents (tap to open/close)
- Reasons why Kakeru Koumuten is chosen for solar panel installation in Shinagawa, Tokyo
- Roof inspection before installing solar panels
- Possible subsidies and grants available in Shinagawa, Tokyo
- Price list for solar panel installation and storage battery installation
- Breakdown of installation capacity, equipment, and construction costs
- Self-estimation and financial simulation for solar power generation
- Customer testimonials
- Case studies of solar panel installations
- How to choose a solar panel installation company in Shinagawa, Tokyo
- Benefits of introducing solar equipment
- Points to consider when introducing solar power generation
- How to choose solar panels
- Frequently asked questions about solar construction and storage battery construction in Shinagawa, Tokyo
- If you are looking for a solar panel installation company in Shinagawa, Tokyo, contact Kakeru Koumuten
- Characteristics of Shinagawa, Tokyo and points for solar construction
- Service area in Shinagawa, Tokyo
Reasons why Kakeru Koumuten is chosen for solar panel installation in Shinagawa, Tokyo
Regarding the reasons why we are entrusted with solar panel installation by customers in Shinagawa, Tokyo,
“Our strengths in solar panel installation that cannot be imitated by other companies”
have received high praise from many customers.
so we would appreciate it if you could compare our estimates with those of other companies.
Because we are confident, we welcome multiple estimates!
1. We also handle exterior renovations other than solar panel installation!
Issues such as leaks that occur during 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 and issues after installation!
Kakeru Koumuten 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.Specialized Equipment for Exterior Renovation
Kakeru Koumuten 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 necessary scaffolding materials for temporary scaffolding based on 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 related to 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, enabling us torespond quickly in emergencies!
Sorting and Transportation of 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 Remodeling 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 installed on roofing materials!
We can also provide simulations of the revenue and installation costs when introducing solar panels!
Since roofing and exterior wall work often accompany projects, we also have samples of roofing materials and models that explain the structure, allowing for detailed explanations!
3.All Work Performed by Our Own Team
One of Kakeru Koumuten’s major strengths is its complete in-house construction.
By having a consistent system from inquiry to project completion, Kakeru Koumuten can provide high-quality roof renovations at reduced costs.
Additionally, one representative will handle everything from the estimate to the completion of the work.
Since the same person will manage sales and construction, smooth communication is possible.
We can provide consistent in-house construction from temporary scaffolding installation to exterior wall painting and 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 specialists, giving us confidence in our construction techniques.
We can also handle large-scale roof projects for factories and other facilities!
5. Warranty and Aftercare
In addition to the manufacturer’s warranty for solar panel installation, we also provide our own construction warranty (leakage warranty)!
(The construction warranty for solar panel installation is 10 years. Depending on the condition of the roof before installation, a roof renovation may be required to provide the warranty. The construction warranty is separate from the manufacturer’s product warranty, and the scope and conditions may vary based on the warranty details.)
Aftercare is available annually, and we send out notification DM each year.
If you have questions about the warranty, please click on the image above!
6. Flexible and Prompt Response
Our company is equipped to handle various roofing troubles and situations.
If you cannot access the roof at high altitudes, we can utilize a drone to assist!
During leak investigations, we can also conduct surveys using a thermal imaging camera.
If the power generation of the solar panels decreases due to dirt, we can provide cleaning with a specialized brush.
We will respond according to the customer’s wishes.
7. Human Resource Development
We create various roof models to conduct practical training for skill enhancement.
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 “financial simulation” that takes into account loan interest rates and electricity costs.
The financial 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 consider and disadvantages!
We encourage you to obtain comparative estimates and review plans from other companies!
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 (rooftop waterproofing). If the remaining lifespan of the roofing material is short, we may suggest a roof renovation first. |
| 2. Condition of the Substrate and Waterproof Sheet | If the sheathing or roofing (waterproof sheet) under the roofing material is damaged, it 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 can 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 shape and size of the roof determine the number of panels that can be installed (installation capacity). The number of panels that can be installed varies depending on the size of the panels, so we will compare based on the overall output of the roof. |
| 5. Fixing Method and Waterproofing Details | We will confirm whether the method involves drilling holes in the roofing material for fixing or using brackets to secure the roofing material. The fixing method varies by construction method, 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. After investigating the existing roof, substrate, and load-bearing capacity, replacing with 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 any steps 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 fixed parts, cracks or deterioration of slate, condition of the substrate. If deterioration is advanced, consider roof overlay (cover method) or replacement first. |
| Tile Roof | Fixed with brackets and methods suited to the type of tile (even methods that do not drill holes in the tiles will fix to the substrate) | Type and condition of tiles, substrate, load-bearing capacity. Depending on the investigation results, there may be methods to replace with lighter roofing materials before installation. |
| Metal Roof (Horizontal and Vertical) | Fixed with catch-type brackets that grip the roof material (depends on the combination of roof material and brackets) | Whether the roof material and brackets are compatible, installation conditions from the roof material manufacturer. If compatible, methods that do not drill holes may be available. |
| Flat Roof / Rooftop | Fixed by installing a frame | Type and deterioration status of the waterproof layer, waterproofing around the frame. Consider in conjunction with the timing of waterproofing work. |
If you plan to renovate the roof 10 to 20 years after installation, there will be additional costs for removing and reinstalling solar panels. If the roof is deteriorating, renovating to a highly durable roofing material before installation may help reduce costs in the long run.
Kakeru Koumuten Co., Ltd. specializes in roofing work and can also handle the removal and reinstallation of solar panels in-house, so please consult us according to the condition of your roof!
▶ Click here for roof renovations in Shinagawa, Tokyo
Potential Subsidies and Grants in Shinagawa, Tokyo
If you are introducing solar panels or storage batteries in Shinagawa, Tokyo, there is a possibility that the systems from the “National Government,” “Tokyo Metropolitan Government,” and your local “Shinagawa Ward” may apply.
The following is based on information confirmed on the official pages of each system as of October 7, 2026. The application status may change depending on the budget, so please check the latest information before contracting or starting work.
Eligibility Conditions and Application Timing for Subsidy Programs
| Program | Main Eligibility Conditions | Subsidy Amount | Application Period & Status |
|---|---|---|---|
| Tokyo “Household Solar Power Generation Promotion Project” | Individuals, corporations, or management associations installing unused solar power systems (output under 50kW, JET certification, etc.) in residential properties within Tokyo. The generated power must be used in the residential part. Pre-application is required | Existing homes: 15,000 JPY per kW for up to 3.75kW (maximum 450,000 JPY), 12,000 JPY per kW for over 3.75kW and under 50kW New homes: 12,000 JPY per kW for up to 3.6kW (maximum 360,000 JPY), 10,000 JPY per kW for over 3.6kW |
For the fiscal year 2026, pre-applications are being accepted from May 29 (will end once the budget is reached). From the pre-application for fiscal year 2026, submission of a certificate issued by a financial institution during the performance report is mandatory |
| Tokyo “Household Storage Battery Promotion Project” | Owners of eligible devices (storage batteries registered with SII) excluding national and local governments. Must be installed between April 1, 2026, and March 30, 2027. If applying after October 1, 2026, only products registered with the national SII for fiscal year 2026 are eligible | Storage battery package: 100,000 JPY per kWh (maximum 1,200,000 JPY per household) Additional for participating in DR demonstration (100,000 JPY per unit; 150,000 JPY per unit if energy management devices are installed) Expansion of storage battery units: 60,000 JPY per kWh (maximum 720,000 JPY per household) |
For the fiscal year 2026, pre-applications are being accepted from May 29. Grant applications and performance reports will be accepted from June 30 |
| Shinagawa Ward “Shinagawa Zero Carbon Action Subsidy (Solar Power Generation System & Storage Battery System)” | Residents, small business owners, etc. (installations in business premises under 150 square meters are A, management associations, etc. and small business owners with installations over 150 square meters are B). Devices installed between April 1, 2026, and March 15, 2027, are eligible, and applications must be made after installation is complete | Solar power generation: 50,000 JPY per kW (maximum A 200,000 JPY, B 500,000 JPY) Storage battery: 30,000 JPY per kWh (maximum 300,000 JPY for both A and B) |
Application period is from May 25, 2026, to March 15, 2027. Applications for residents (A) have exceeded the planned number (100), and currently, acceptance is suspended (may resume if there are remaining funds). Applications for management associations, etc. (B) have a planned number of 10, and the acceptance status is listed as “ample” (updated October 2, 2026) |
| National “DR Household Storage Battery Project” (Fiscal Year 2025 Supplement) | Newly introducing household storage systems that can be utilized for DR (demand response) with registered products | Calculated based on an initial effective capacity of 34,500 JPY per kWh (subsidy rate within 3/10; maximum 600,000 JPY per application) | The budget was reached on May 29, 2026, and the public 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) | Storage batteries are one of the eligible facilities, but they must be combined with essential works such as insulation renovations of windows (openings) and structures; applications cannot be made for just the installation of storage batteries. Solar panels are not included as eligible facilities | Storage Battery: 96,000 JPY/unit | Ends as soon as the budget limit is reached. As of October 5, 2026, the application amount for renovations is displayed as 8% of the budget on the official site. Please check the application status on the official site. |
The Tokyo solar power and storage battery 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. The subsidy in Shinagawa Ward is a system where applications are made after installation is completed, and the quota for residents in the 2026 fiscal year has exceeded the planned number, and applications are currently suspended. 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 will provide guidance on eligibility conditions and application periods for each program after confirming them.
National Subsidy “DR Home Storage Battery Project (Support Project for Introducing Home Storage Systems for DR Resource Implementation)”
The national government has been implementing the “DR Home Storage Battery Project” to support the installation of home storage batteries.
This program targets those who are introducing new storage systems of registered products that can be utilized for demand response (DR), and in the 2025 fiscal year 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 2025 fiscal year supplementary application amount reached the budget on May 29, 2026, and the public recruitment has ended. The official site also states that there are no plans to resume public recruitment, and applications are currently not possible. Please check the official site for future public recruitment.
Additionally, there are currently no subsidies confirmed for the installation of solar panels on existing homes.
👉 Click here for the official site of the DR Home Storage Battery Project
Tokyo “Promotion Project for Introducing Solar Power Generation in Homes”
This subsidy is for those who are installing unused solar power generation systems in residential homes 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 the installation of rooftop structures 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 making a prior application and then applying for the subsidy after installation, and starting from the 2026 fiscal year prior application, submission of a certificate issued by a financial institution during the performance report is now mandatory.
According to the official page of Tokyo, pre-registration is being accepted from May 29, Reiwa 8. It will end once the budget is reached, so please check the official page for the registration status.
👉 Here is the official page of Tokyo (Cool Net Tokyo)
Tokyo’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 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 per kWh (maximum 720,000 JPY 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 Reiwa 8 fiscal year by the national SII will be eligible.
The official page of Tokyo states that pre-registration is being accepted from May 29, Reiwa 8. Please check the official page for detailed information, including conditions for combination with solar power generation.
👉 Here is the official page of Tokyo (Cool Net Tokyo)
Shinagawa Ward “Shinagawa Zero Carbon Action Subsidy (Solar Power Generation System and Battery System)”
This subsidy is for those who have installed solar power generation systems or battery systems within the ward. Applications are to be made after the installation of the equipment is completed, not before the construction. The eligible applicants are divided into “A” for residents and small business owners (installations at business sites with a total floor area of less than 150 square meters) and “B” for management associations and small business owners (installations at business sites with a total floor area of 150 square meters or more).
●Solar power generation: 50,000 JPY per kW output (maximum 200,000 JPY for A, 500,000 JPY for B)
●Battery: 30,000 JPY per kWh of storage capacity (maximum 300,000 JPY for both A and B)
The eligible equipment must be installed between April 1, Reiwa 8 and March 15, Reiwa 9, and the eligible expenses for the subsidy are defined as “costs for the equipment itself, accessories, and installation.” The application period is from May 25, Reiwa 8 to March 15, Reiwa 9.
However, according to the official page of Shinagawa Ward (updated on October 2, Reiwa 8), the solar power generation and battery systems for residents (A) have reached the “planned number exceeded” status (planned number 100 cases) and are currently closed for applications. Applications received by 5:15 PM on the day the planned number is reached will be treated as simultaneous and will be drawn by lottery, and if there are remaining budget funds, applications may be reopened (notification will be made in the ward newsletter and on the website). For management associations, etc. (B), the planned number is 10 cases and is listed as “ample availability.” Please check the official page for the latest application status.
👉 Here is the official page of Shinagawa Ward
Solar Panel Installation & Battery Installation Price List
⇧Service Menu | For Costs of Solar Panel Installation & Battery Installation, Click Here
⇧Service Menu | For Costs of Solar Panel Removal & Water Heater Removal, Click Here
Breakdown of Installation Capacity, Equipment, and Construction Costs
The costs for solar panels and batteries should be confirmed by separating them into “Equipment Costs (Device Costs)” and “Construction Costs.”
Even for the same “Complete Solar Panel Installation,” the amount can vary significantly depending on the installation capacity, equipment grade, and roof condition.
Considerations for Installation Capacity (kW) and Battery Capacity (kWh)
The installation capacity of solar panels is determined by “the output of one panel (W) × number of panels”, with the unit being kW (kilowatts). The battery is compared in terms of the amount of electricity it 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 shape, orientation, and size of the roof. At Kakeru Koumuten, we create a layout diagram from the blueprints and on-site survey to present the installation capacity.
On our pricing page, we list solar panels as approximately 800,000 yen to 1,200,000 yen for 3 to 5 kW, and 1,200,000 yen to 1,900,000 yen for 6 to 10 kW. (These are just rough estimates and may vary depending on the length of wiring, scaffolding area, existing roofing materials, and panel layout.)
▶ Installation Menu | Costs for Solar Panel Installation and Battery Installation
Items to Confirm in the Estimate (Cost Verification)
When comparing estimates, it’s common to compare different capacities and equipment just by looking at the amounts. Please check if the following items are clearly stated in each company’s estimate!
| 1. Solar Panels | Manufacturer, model number, output of one panel (W), number of panels, and total installation capacity (kW) are listed. |
| 2. Power Conditioner | Manufacturer, model number, capacity, number of units, installation location (indoor/outdoor). Also check if it is a type that controls the battery together. |
| 3. Battery | Manufacturer, model number, capacity (kWh), range usable during a power outage (whole house or specific circuits), installation location. |
| 4. Mounting Frame and Hardware | Name of the hardware suitable for the roofing material and the method of fixing (whether it is a method that drills holes or a method that clamps and secures). |
| 5. Wiring and Electrical Work | Wiring route and length, work around the distribution board, and whether there is a monitor to check the power generation amount. |
| 6. Roof Reinforcement and Waterproofing | Details of waterproofing treatment for fixed parts, whether necessary roof repairs and substrate reinforcements are included. |
| 7. Applications | How much support is included for applications to the power company, certification applications for selling electricity (FIT), and subsidy applications. |
| 8. Scaffolding | Scope and quantity of scaffolding. If it is simultaneous with roof work or exterior painting, check that the same scope and quantity are not double-counted. |
| 9. Removal and Disposal | Whether the removal of existing solar 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-excluded, conditions under which additional costs may arise, and details and duration of manufacturer and workmanship warranties. |
If the capacities are different, the amounts and power generation will also change. Kakeru Koumuten welcome comparisons, so if you bring estimates from other companies, we will explain the differences by item!
Self-Estimate and Profit Simulation for Solar Power Generation
With the simulator above,
you can get an estimated quote and income simulation for up to 30 years!
If you know the total installation capacity of solar panels on the roof and the capacity of the storage battery, you can obtain an estimated quote and income simulation!
*The simulation results are estimates. Actual income may vary based on assumptions such as electricity rates, self-consumption ratios, selling prices, and costs for equipment inspection or 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 Arrangement |
| Fixed using catch type hardware gripping the horizontal metal roof (Catch Method) |
| Price Range |
| 2,200,000 JPY – 2,300,000 JPY *Due to the grant being provided, the actual burden amount is approximately 1,000,000 JPY Estimated recovery period for construction costs: about 8-9 years (self-consumption) *The grant amount and recovery estimate are based on the system and calculations at the time of construction, and may differ under the current system. |
| Construction Period |
| About 3 days |
| Completion Month |
| April 2025 |
| Inquiry Details |
| I am considering the installation of solar panels and storage batteries. I heard that grants are available, and I would like to know how much can be provided. |
Our Proposal
We visited to provide an estimate and created a layout diagram for the solar panels from the drawings!
The layout diagram shows the arrangement of solar panels when placed on the roof.
Since we can also determine the installation capacity, it allows for power generation simulations and financial simulations.
We have also understood the expected grant amount, so we explained this to the customer along with the estimate!
How to Choose a Solar Panel Installation Contractor in Shinagawa, Tokyo
There are many solar panel installation contractors available in Shinagawa, Tokyo, and you may be unsure which contractor to choose.
Therefore, when requesting solar panel installation and battery storage installation work, let’s confirm the following 4 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 (3 companies as 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.
Have knowledge about roofs as well as solar panels
Defective installation of solar panels can sometimes be caused by a lack of knowledge and verification regarding roofs and waterproofing.
While knowledge about solar panels is certainly important, understanding the roof and waterproofing at the installation site of the solar panels is also crucial.
⚠︎Examples of troubles caused by insufficient verification of roofs and waterproofing
・Solar panels were installed on a deteriorated roof, resulting in leaks
・Solar panels were installed on a roof with a short lifespan, necessitating a renovation to detach and reattach the solar panels within a few years
・Misjudgment of the type of waterproofing led to incorrect processing and subsequent leaks
and more
When installing solar panels, understanding the condition and type of the existing roof allows for installation that avoids unnecessary expenses and unexpected troubles.
▶ Go to “Roof Verification Before Installing Solar Panels” in this article
Confirm the 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 coverage, disclaimers, and cost conditions.
Solar panels and battery storage units come with manufacturer warranties, but also check for the existence of workmanship warranties in case leaks occur after installation!
For contractors that offer workmanship 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 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 of hidden areas during aftercare, you can more easily detect abnormalities early and prevent major repairs or failures!
Kakeru Koumuten Co., Ltd. offers a rain leak warranty as part of the workmanship warranty for solar panel installations. (The warranty for solar panel installations is 10 years, and depending on the condition of the roof before installation, we may not be able to provide the warranty without performing roof renovations.)
We also provide aftercare maintenance, sending out annual DM notifications!
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 work 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,
“Check the items in the estimate”
“Type of solar panel”
“Warranties and after-sales services”
let’s carefully compare and make a judgment! If the rank of auxiliary materials is low or if steps are skipped, costs can be reduced, so avoid making decisions based solely on price!
▶ Go to “Breakdown of installation capacity, equipment, and construction costs” in this article
Check if they provide support for subsidy applications
There may be subsidies available for solar panel and storage battery installations, but if the order of procedures is incorrect or if there are deficiencies in the documents, the grant may not be awarded.
Since there are systems that require prior application, such as Tokyo’s subsidies, it is reassuring to have a contractor who can support you with the preparation of necessary documents and the flow of procedures.
Complete the procedures specified for each system (for Tokyo’s subsidies, prior application is required) before proceeding with the construction!
For Tokyo’s subsidies, after installation, you will need to submit a grant application and performance report, and it will be awarded after a review! (The flow of procedures varies by system)
▶ Go to “Subsidies and grants that may be applicable in Shinagawa Ward, Tokyo” in this article
Benefits of Introducing Solar Equipment
The benefits of introducing solar panels are as follows!
Benefit 1: Economic Benefits
The biggest advantage of introducing solar panels is the economic benefit!
The selling price of electricity has decreased compared to ten years ago, but by consuming the electricity generated, you can reduce the amount of electricity purchased from the utility company and gain benefits!
As electricity costs rise, the ability to cover your power consumption with solar power becomes attractive!
If you plan to use the generated electricity at night, installing a storage battery is essential!
Furthermore, the selling price (FIT) for residential use (less than 10kW) will be set as “24 yen/kWh for the first four years, and 8.3 yen/kWh from the fifth to the tenth year” for certifications after October 2025, and the same price will apply for the 2026 fiscal year. After the fifth year, it is likely to be more advantageous to use it at home (self-consume) rather than sell it, so combining it with a storage battery is also an option.
👉 Ministry of the Environment | For purchase prices and periods, click here
Advantage 2 Subsidies can be utilized!
The conditions and amounts of subsidies vary by prefecture and municipality, but if you meet the conditions, you may be able to utilize subsidies!
Reducing the actual burden amount through subsidies is a significant advantage!
In the case of Shinagawa Ward, there is a possibility of being eligible for the programs of the national government, Tokyo Metropolitan Government, and Shinagawa Ward. Currently, applications for the fiscal year 2026 for residents of Shinagawa Ward are suspended (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 such as power conditioners do have operational noise.)
Advantage 4 Heat insulation effects are expected!!
By installing the panels on the roof or rooftop, they block direct sunlight from hitting the roof.
Especially in summer, it can help reduce the temperature of the roof, providing expected heat insulation effects!
（This does not improve the insulation performance of the building itself）
Benefit 5 Electricity can be used even during power outages!!
If a storage battery is installed, it 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 capabilities, 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 the solar panels are installed.
If you perform roof renovations 10 to 20 years later, there will be costs for removing and reinstalling the solar panels.
If the existing roof is deteriorated, it is reassuring to renovate it with durable roofing materials before installing the 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 brackets to the roofing material or 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 the brackets, and it cannot be used with all metal roofs)
Catch-type base hardware 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-bearing capacity, switching to a lighter roof may also be an option if necessary.
How to Choose Solar Panels?
There are many manufacturers of solar panels, and their output and costs vary.
It is not simply a matter of “this manufacturer has the best solar panels”; it is important to choose solar panels that are suitable for your life plan and building!
Here are some points to consider when comparing solar panels!
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 power can be generated in a limited area, and it is better to generate more power!
Solar panels vary in size and output depending on the manufacturer.
A panel with an output of 350W and a panel with an output of 400W may seem at first glance that the higher output panel is better.
However, if the size of the panel does not fit well with the roof, “20 panels of 350W can be installed” and “15 panels of 400W can be installed,” meaning the number of panels that can be installed on the same roof varies 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 the calculation of total output (kW). The actual power 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 after 10 years and 20 years.
The degree of output reduction after long-term use varies by product. The manufacturer’s output guarantee value is a standard figure for warranty purposes and does not indicate the actual degradation rate or power generation itself.
Choosing solar panels by considering the degradation rate as well as 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 widely!
Since longer warranties are generally better, 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 Shinagawa, Tokyo
We have compiled common questions from customers considering the installation of solar panels and storage batteries in Shinagawa, Tokyo. (Tap to open the answers)
How much does it cost to install solar panels and storage batteries in Shinagawa, 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.
For cost estimates by capacity, please refer to the solar panel installation and storage battery installation pricing page. We will create a layout diagram based on the drawings and site survey and provide a free estimate!
Are there any subsidies available for solar power and storage battery installation in Shinagawa, 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 3.75kW, 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 stated on the official Tokyo (Cool Net Tokyo) page. In Shinagawa, there is the Shinagawa Zero Carbon Action Grant (for solar power generation, 50,000 yen per kW with a maximum of 200,000 yen for residents, and for storage batteries, 30,000 yen per kWh with a maximum of 300,000 yen), but the quota for residents in the 2026 fiscal year has exceeded the planned number, and applications are currently suspended, as noted on the official Shinagawa 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 depends on the system. Tokyo’s subsidies require pre-application, while Shinagawa’s grant allows applications after installation is completed. Conditions such as whether you can contract and start construction before applying vary by system, so please confirm before signing a contract.
The order of procedures varies by system, so please check before signing a contract 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 Co., Ltd. is a specialized exterior renovation company strong in roofing work, so we will check the condition of the roof before installation and suggest methods such as roof overlay (cover method) or complete replacement if deterioration is progressing.
My roof is old. Should I do a roof renovation first?
It depends on the condition of the roof. If a roof renovation is needed within 10 to 20 years after installation, there will be additional costs for removing and reinstalling solar panels. If the remaining lifespan of the roof is short, it may be more cost-effective to renovate with durable roofing materials before installation.
Please consult us on how to proceed with the installation after checking the condition of the roof through a site survey!
Should I install a storage battery together with the solar panels?
If you want to use the generated electricity at night or prepare for power outages, simultaneous installation is recommended. The selling price of electricity will be 8.3 yen/kWh after the fifth year, making it more advantageous to use it in your home rather than selling it.
Additionally, the subsidy for storage batteries in Tokyo (for Reiwa 8, it is 100,000 yen per kWh, with a maximum of 1,200,000 yen per household) is aimed at increasing self-consumption of electricity generated by solar power. In Shinagawa Ward, the storage battery system is also included in the subsidy program (the application for the Reiwa 8 ward resident frame is currently closed). You can compare “solar only” and “solar + storage battery” through a financial simulation.
How many kW can be installed on my roof? Is it okay for a north-facing roof or one that has 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 based on the drawings and site survey, and provide you with the installation capacity and power generation simulation.
Shinagawa Ward has areas with plateaus and lowlands, and the coastal area has different land formations, so the shape and orientation of the roof, as well as the shadows cast by surrounding buildings, vary for each house. You can check the expected 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 if roofing work is done simultaneously or depending on the shape of the roof and installation capacity.
Please note that there will be an additional 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 electricity?
For residential use (under 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 prices will apply in the 2026 fiscal year.
The idea is to recover the initial costs more quickly in the first four years and then focus on self-consumption. Kakeru Koumuten provides a financial simulation that takes into account loan interest rates and electricity prices.
Can you handle 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 special brush if the power generation decreases due to dirt.
Since the roof is a place that is difficult to check by yourself, please feel free to consult us if you have any concerns.
Can you also renovate roofs that already have solar panels installed?
It is possible. Kakeru Koumuten Co., Ltd. can detach and reattach solar panels in-house, allowing us to perform roof overlay (cover method) or re-roofing after removing the panels, and we will handle everything consistently until reinstallation. The removed panels can be stored in our own warehouse.
For costs, please refer to the solar panel detachment and hot water heater removal pricing page.
If you are looking for a solar panel installation company in Shinagawa, Tokyo, please consult Kakeru Koumuten
Our company handles many exterior renovations, including solar panels, roof work, and exterior wall work in Shinagawa, Tokyo.
We receive requests from many customers, including renovation companies and real estate agencies!
Kakeru Koumuten promises “high-quality renovations at low cost”, and we have received great feedback from numerous customers.
We continue to update our construction achievements every year and will strive to improve quality to satisfy even more customers in the future.
Our company can perform all exterior renovations, not only roof overlay and re-roofing but also partial roof repairs, exterior painting, and exterior wall cover methods.
We are also 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 the best solutions for your specific requests.
We will never propose unnecessary work that prioritizes profit!
We always stand in the customer’s position and will propose the optimal construction plan!
We are confident that we will not be outdone by other companies in terms of cost, quality, and organization for exterior work!
We welcome competitive estimates with confidence!
Estimates are completely free, and if our company is found to be inferior to others, you are free to decline!
Characteristics of Shinagawa, Tokyo and Points of Solar Work
The area of Shinagawa Ward is 22.84 square kilometers. The terrain consists of a part of the Musashino Plateau in the southeastern area and lowlands and reclaimed land located to the east, with a coastal area facing Tokyo Bay. Below are the characteristics of the terrain in Shinagawa Ward, Tokyo, and points to consider when installing solar panels and storage batteries. (Tap to open)
View the characteristics of Shinagawa Ward, Tokyo, and points for solar installation
■ A mix of plateaus, lowlands, and reclaimed land. Check scaffolding, delivery, and shadows for each site
According to district materials, the lowlands spread around Gotanda and Osaki along the Meguro River, and near the coast in Shinagawa and Oi. Land use is said to be approximately 57% residential, and in sites where the distance to neighboring houses is close, the shadow cast by neighboring houses, the space for scaffolding, and the delivery routes for equipment vary from house to house. At Kakeru Koumuten, our own scaffolding team plans scaffolding to match the site, creates layout diagrams from drawings and site surveys, and you can confirm this through power generation simulations.
■ Check flood and storm surge hazard maps. Pay attention to the installation location of equipment
Shinagawa Ward has created hazard maps for floods (Shinagawa Ward Flood Hazard Map, Shinagawa Ward Tamagawa Flood Hazard Map) and storm surges (Storm Surge Flood Hazard Map). Depending on where the power conditioner and storage batteries are installed, separate from the panels on the roof, the impact during flooding may vary. Please check the flood assumptions for your residence on the district’s hazard map and consult about the installation location and height in conjunction with the installation conditions of the manufacturer you are using.
■ The types of roofs and their ages vary from house to house. Check the roof and waterproofing before installation
Even within the same ward, the types of roofs, their ages, and the shapes of the sites vary from house to house. At Kakeru Koumuten, we will check the type and condition of the roof and the situation of the site before installation, and propose methods for securing, waterproofing details, and scaffolding plans.
■ The annual sunshine hours at the Tokyo Observatory is about 1,927 hours
According to the Japan Meteorological Agency’s average values (1991-2020), the annual sunshine hours at the Tokyo Observatory is about 1,927 hours, with January (about 193 hours) being the most and June during the rainy season (about 124 hours) being the least. (This is a reference value, not an observation value within Shinagawa Ward.)
The amount of power generation in Shinagawa Ward can also change due to shadows from surrounding buildings, so it is important to conduct annual power generation simulations and choose the capacity of storage batteries to match the times when electricity is used the most.
Our company handles many exterior construction and solar power projects in Shinagawa, 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 for any sudden troubles!
Service Area in Shinagawa, Tokyo
Kakeru Koumuten Co., Ltd. accepts requests throughout Kanagawa Prefecture and all of Tokyo.
List of Areas in Shinagawa, Tokyo
Ebara, Shinagawa Ward / Oi, Shinagawa Ward / Osaki, Shinagawa Ward / Katsushima, Shinagawa Ward / Kamiosaki, Shinagawa Ward / Kitashinagawa, Shinagawa Ward / Koyama, Shinagawa Ward / Koyamadai, Shinagawa Ward / Togoshi, Shinagawa Ward / Nakanobu, Shinagawa Ward / Nishi-Oi, Shinagawa Ward / Nishi-Gotanda, Shinagawa Ward / Nishi-Shinagawa, Shinagawa Ward / Nishi-Nakanobu, Shinagawa Ward / Hatanodai, Shinagawa Ward / Higashi-Oi, Shinagawa Ward / Higashi-Gotanda, Shinagawa Ward / Higashi-Shinagawa, Shinagawa Ward / Higashi-Nakanobu, Shinagawa Ward / Hiratsuka, Shinagawa Ward / Hirocho, Shinagawa Ward / Futaba, Shinagawa Ward / Minami-Oi, Shinagawa Ward / Minami-Shinagawa, Shinagawa Ward / Yashio, Shinagawa Ward / Toyocho, Shinagawa Ward
・Trust Kakeru Koumuten for exterior wall painting in Shinagawa, Tokyo!
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・Trust Kakeru Koumuten for exterior renovations in Shinagawa, Tokyo!
・Kakeru Koumuten Co., Ltd. project achievements
・Kakeru Koumuten Co., Ltd. aftercare services
・Kakeru Koumuten Co., Ltd. service menu and price list
・Kakeru Koumuten Co., Ltd. staff blog and announcements
・Explaining the importance of comparative estimates and key points!
・Top 12 solar power 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? Key points for site selection included!
・Check out our solar power estimate 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!
