Leave the installation of solar panels in Suginami, Tokyo to Kakeru Koumuten Co., Ltd.!
For solar panel and storage battery installation in
Suginami Ward, Tokyo,
Kakeru Koumuten is at your service!
Kakeru Koumuten is a specialized exterior renovation company headquartered in Aoba Ward, Yokohama City.
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 Suginami Ward”
“Costs for Solar Panel and Storage Battery Installation”
“Subsidies Available for Solar System Installation in Suginami Ward”
We will also explain the above three points!
Installing solar panels carries risks such as“the occurrence of leaks” and other troubles.
To ensure a satisfactory solar panel installation, we recommend obtainingthree estimates!
Table of Contents (tap to open/close)
- Reasons Why Kakeru Koumuten is Chosen for Solar Panel Installation in Suginami, Tokyo
- Roof Inspection Before Installing Solar Panels
- Possible Subsidies and Grants Available in Suginami
- Price List for Solar Panel and Storage Battery Installation
- Breakdown of Installation Capacity, Equipment, and Construction Costs
- Self-Estimate and Profit Simulation for Solar Power Generation
- Customer Testimonials
- Case Studies of Solar Panel Installations
- How to Choose a Solar Panel Installer in Suginami, 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 Suginami
- If You’re Looking for a Solar Panel Installer in Suginami, Contact Kakeru Koumuten
- Characteristics of Suginami, Tokyo and Key Points for Solar Installation
- Service Area in Suginami, Tokyo
Reasons Why Kakeru Koumuten is Chosen for Solar Panel Installation in Suginami, Tokyo
Regarding why our company is entrusted with solar panel installation by customers in Suginami, Tokyo,
One reason is that “Kakeru Koumuten covers Kanagawa and Tokyo as its service areas”,
but we also have “strengths in solar panel installation that cannot be imitated by other companies”, which 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 Beyond Solar Panel Installation!
Troubles such as leaks that occur during solar panel installation may be caused by insufficient checks on the roof and waterproofing at the installation site.
Even if you are knowledgeable about solar panels, there are cases where the roof and waterproofing at the installation site are outside your expertise, so caution is necessary.
It is reassuring to have knowledge about the roof to avoid maintenance and troubles after installation!
Kakeru Koumuten Co., Ltd. is strong in roofing work and can also detach and attach solar panels in-house, allowing for quick responses to maintenance and urgent troubles after solar panel installation!
2.Facilities Specialized in Exterior Renovation
Kakeru Koumuten Co., Ltd. has organized 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 centered in Yokohama City, Kanagawa Prefecture 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, allowing us to assemble scaffolding ourselves.
By performing scaffolding work with our own scaffolding team instead of outsourcing, we can also cut costs on scaffolding work.
We have scaffolding materials for approximately 50 single-family homes!
Even in Suginami Ward, where residential areas are expanding, our own scaffolding team plans the scaffolding according to the site 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, we canpurchase materials at a lower cost!
Additionally, since we always have stock of roofing materials, we can providequick responses in emergencies!
Sorting and transporting waste materials in-house
The installation of solar panels often involves roofing work, generating various waste materials such as paint, wood, and metal.
By sorting and recycling waste materials, we can significantly cut waste disposal costs.
Exterior renovation dedicated showroom
In the showroom, not only can you have meetings, but you can also
check the actual foundation brackets for solar panels and see how they are installed on the roofing materials!
It is also possible to simulate the revenue and installation costs when introducing solar panels!
Since roofing and exterior wall work often accompany each other, we also provide samples of roofing materials and models that show the structure, allowing for detailed explanations!
3.All Work Performed by Our Own Team
One of Kakeru Koumuten’s major strengths is all work performed by our own team.
By maintaining a consistent system from inquiry to project completion, Kakeru Koumuten can provide high-quality roof remodeling at reduced costs.
Additionally, one representative will handle everything from the estimate to project completion.
Since the person in charge does not change, whether it’s sales or construction management, smooth communication is possible.
We can perform consistent in-house construction from temporary scaffolding setup to exterior wall painting and roof remodeling!
4. Various Permits and Skilled Workers
We have obtained construction industry licenses and permits for industrial waste collection and transportation!
We also have nationally certified sheet metal workers and painting technicians, giving us confidence in our construction techniques.
We are capable of handling large-scale roofing projects such as factories!
5. Warranty and Aftercare
In addition to the manufacturer’s warranty, our solar panel installation work comes with our own workmanship warranty (leakage warranty)!
(The workmanship 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 workmanship warranty is separate from the manufacturer’s product warranty, and the coverage and conditions vary based on the warranty details.)
Aftercare maintenance is available annually, and we send out notification DM every year.
If you have any questions about the warranty, please click on the image above!
6. Flexible and Prompt Response
We are equipped to handle various roof troubles and situations.
Even if you cannot access the roof at high places, we can respond using a drone!
During leakage investigations, we can also conduct inspections using a thermal imaging camera.
If the power generation of the solar panels decreases due to dirt, we can also clean the solar panels using a specialized brush.
We will respond according to your preferences.
7. Human Resource Development
To improve skills, we create various roof models and conduct practical training.
Since the construction methods vary depending on the shape and slope of the roof, we regularly provide technical training so that each staff member can handle various cases.
8. Creation of Easy-to-Understand Materials and Simulations
At Kakeru Koumuten Co., Ltd., in addition to “estimates”, “layout diagrams”, and “power generation simulations”, we also provide a “solar installation guidebook” and a “financial simulation” that takes into account loan interest rates and electricity costs.
The financial simulation can project cumulative income and expenses over 20 to 30 years.
Even customers who are not familiar with solar installations will find our materials easy to understand, including important points and potential drawbacks!
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.
It is crucial to confirm “whether it is safe to install them directly on the current roof” before installation, as this is the key point to prevent leaks and unnecessary expenses!
Kakeru Koumuten, specializing in roofing, has summarized the items to check before installation.
| 1. Type of roofing material and age | The method of securing the panels varies depending on the roofing material, such as slate, tiles, metal roofs, or flat roofs (roof waterproofing). If the remaining lifespan of the roofing material is short, we may suggest a roof renovation first. |
| 2. Condition of the substrate and waterproof sheet | If the sheathing or roofing (waterproof sheet) beneath the roofing material is damaged, it can affect the fastening strength and waterproofing. We will also check for any signs of leaks. |
| 3. Orientation, slope, and shadows of the roof | The orientation and slope of the roof surface, as well as shadows from neighboring houses, trees, and utility poles, can affect power generation. We will create a layout diagram based on the drawings and the site, and you can confirm this with the power generation simulation. |
| 4. Shape of the roof and available installation area | The shape and size of the roof determine the number of panels (installation capacity) that can be placed. The number of panels that can be installed varies depending on their size, so we will compare based on the total output of the roof. |
| 5. Method of securing and waterproofing details | We will check whether the panels will be secured by drilling holes into the roofing material or by using brackets to hold the roofing material. The method of securing varies by technique, so please confirm the waterproofing treatment of the fastening 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 be an option if necessary. |
| 7. Location of equipment installation and wiring | We will confirm the installation locations for the power conditioner and storage battery, as well as the wiring route to the distribution board. The length of the wiring will also affect costs. |
Securing 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 the fixing parts, cracks or deterioration of the 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 the 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 framework | Type and deterioration status of the waterproof layer, waterproofing around the framework. Consider in conjunction with the timing of waterproofing work. |
If you carry out roof renovations 10 to 20 years after installation, additional costs for the removal and reinstallation of solar panels will apply. 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 Suginami, Tokyo
Possible Subsidies and Grants in Suginami, Tokyo
When introducing solar panels or storage batteries in Suginami, Tokyo, there is a possibility that the systems of “the national government,” “Tokyo,” and “Suginami” may apply.
The following information is based on the official pages of each system as of October 7, 2026. The application status may change depending on the budget and recruitment period, 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 Metropolitan “Reiwa 8 Year Household Solar Power Introduction Promotion Project” (Cool Net Tokyo) | New installation of certified solar modules in residential properties or their premises within the city, with a system capacity of less than 50kW. Pre-application before installation is required. | Existing homes: 150,000 JPY/kW for 3.75kW or less (maximum 450,000 JPY), 120,000 JPY/kW for over 3.75kW New homes: 120,000 JPY/kW for 3.6kW or less (maximum 360,000 JPY), 100,000 JPY/kW for over 3.6kW (Additional costs for mounting frames, waterproofing work, and renovation defect insurance, etc.) |
Pre-application: From May 29, 2026 Grant application and performance report: From June 30, 2026 to March 30, 2029 |
| Tokyo Metropolitan “Reiwa 8 Year Household Storage Battery Introduction Promotion Project” (Cool Net Tokyo) | New installation of storage batteries in residential properties within the city, with SII registered equipment. This project is intended for simultaneous installation with solar power, but applications can be made for storage batteries alone. Pre-applications after October 1, 2026 will only be eligible for SII registered products for Reiwa 8. | Storage battery package: 100,000 JPY/kWh (maximum 1,200,000 JPY per household) Storage battery unit expansion: 60,000 JPY/kWh (maximum 720,000 JPY per household) (Additional incentives for participating in DR demonstrations, etc.) |
Pre-application: From May 29, 2026 Grant application and performance report: From June 30, 2026 |
| Suginami Ward “Eco Housing Promotion Subsidy” (Subsidy for the Introduction of Renewable Energy, etc.) Reiwa 8 Year | Residents (individuals) installing in homes within the ward, as well as small and medium-sized enterprises and management associations within the ward are eligible. Equipment must be unused and not leased, and the applicant, contractor, and payer must be the same. Both solar power systems and storage batteries are eligible. | Solar power generation: 40,000 JPY per 1kW of nominal maximum output (maximum 120,000 JPY) Storage battery: Fixed amount of 50,000 JPY |
Application period: From April 10, 2026 to February 26, 2027 (Completion period for eligible work: From February 1, 2026 to January 31, 2027) Applications can be made after the completion of work and payment; pre-application is not required. Applications will close once the budget limit is reached. |
| National “DR Household Storage Battery Project” (Reiwa 7 Year Supplement) | New installation of household storage systems that can be utilized for DR (demand response) with registered products. | Calculated based on a standard amount of 34,500 JPY per initial effective capacity of 1kWh (subsidy rate within 3/10; maximum 600,000 JPY per application). | The budget was reached on May 29, 2026, and the application period has ended. (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 work such as insulation renovation of windows (openings) and structures; applications cannot be made for the installation of storage batteries alone. Solar panels are not included as eligible facilities. | 蓄電池：96,000 JPY/unit | Ends as soon as the budget limit is reached. Please check the official website for the application status. |
In Tokyo, a pre-application before installation is required for subsidies. If construction begins beforehand, it may not be eligible for Tokyo’s subsidies, and applying does not guarantee approval. On the other hand, Suginami Ward’s Eco Housing Promotion Grant requires application after the completion of construction and payment, and will end if the budget limit is reached even within the application period. Procedures and eligibility for each system vary, so please confirm before contracting or starting work.
Kakeru Koumuten Co., Ltd. will guide you on eligibility conditions for each system after confirming them.
Tokyo “Reiwa 8 Year Household Solar Power Introduction Promotion Project”
Tokyo is providing subsidies for those installing solar power systems in residential homes through Cool Net Tokyo. The target is systems using certified solar modules with a capacity of less than 50kW, newly installed in residential homes or their premises within Tokyo. A pre-application before installation is required.
For existing homes, the subsidy amount is 150,000 JPY/kW for up to 3.75kW (maximum 450,000 JPY), and 120,000 JPY/kW for over 3.75kW. Additionally, there are supplementary items such as installation of mounting frames, waterproofing work, and renovation defect insurance. The pre-application period is from May 29, 2026, and the application for grants and performance reports is from June 30, 2026, to March 30, 2029. For details on eligible equipment and conditions, as well as budget status, please check the official page.
👉 Cool Net Tokyo | Official page for solar power is here
Tokyo “Reiwa 8 Year Household Storage Battery Introduction Promotion Project”
Tokyo is also providing subsidies for newly installed storage batteries in residential homes. The subsidy amount is 100,000 JPY per kWh for storage battery packages (maximum 1,200,000 JPY/unit), and 60,000 JPY per kWh for additional storage battery units (maximum 720,000 JPY/unit), with additional amounts for participation in DR demonstrations.
Eligible equipment is registered with SII (Environmental Collaboration Initiative). If applying after October 1, 2026, only equipment listed in the Reiwa 8 Year SII registered products will be eligible. This project is intended for simultaneous installation with solar power, but applications can be made for storage batteries alone. The application for grants and performance reports has been open since June 30, 2026.
👉 Cool Net Tokyo | Official page for storage batteries is here
Suginami Ward “Eco Housing Promotion Grant” (Subsidy for Introduction of Renewable Energy, etc.)
Suginami Ward is implementing the Eco Housing Promotion Grant for those who install renewable energy equipment in homes within the ward. Eligible applicants include residents who install equipment in their own homes, residents who own buildings within the ward, small business owners (with representatives residing in the ward), management associations, and medical corporations. The subsidy amount is 40,000 JPY per kW for solar power systems with a nominal maximum output (limit 120,000 JPY), and a flat rate of 50,000 JPY for storage batteries.
The condition is that the equipment is unused and not leased, and the applicant, contractor, and payer must be the same person. Additionally, reapplication for the same type of equipment that has received assistance cannot be made within the useful life. The application period is from April 10, 2026, to February 26, 2027 (the completion period for eligible work is from February 1, 2026, to January 31, 2027), and pre-application is not required. Applications should be submitted at the ward office or by mail after the completion of the work and payment. Even within the application period, acceptance may end when the budget limit is reached, and a lottery may be held. It is estimated that it will take about 2 to 3 months from application to payment. Please check the ward’s procedure guide for the eligibility of combining with Tokyo’s subsidies and necessary documents.
👉 Here is the official page of Suginami Ward (Eco Housing Promotion Subsidy Procedure Guide)
National Subsidy “DR Home Battery Project (Support Project for Home Battery System Introduction for DR Resource Implementation)”
The national government has been implementing the “DR Home Battery Project” to support the installation of home batteries.
This program targets those who are newly introducing registered products’ battery systems that can be utilized for demand response (DR), and in the fiscal year 2025 supplementary budget, the subsidy amount is determined based on a standard amount of 34,500 yen per initial effective capacity of 1 kWh, with a subsidy rate of up to 30% and a maximum of 600,000 yen per application. There are conditions such as that contracts or orders made before the grant decision are not eligible.
However, the fiscal year 2025 supplementary budget reached the application amount on May 29, 2026, and the public recruitment has ended (the previous fiscal year’s supplementary budget also ended public recruitment on July 2, 2025). Applications are currently not possible, so please check the official website for future public recruitment.
Furthermore, there are currently no subsidies confirmed for the installation of solar panels for existing homes.
👉 Here is the official site for the DR Home Battery Project
Solar Panel Installation & Battery Installation Price List
⇧ Service Menu | For costs related to solar panel installation and battery installation, click here
⇧Service Menu | Click here for costs related to Solar Panel Removal and Hot Water Heater Dismantling
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 (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 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 placed on the roof varies for each house based on the shape, orientation, and size of the roof. At Kakeru Koumuten, we create layout diagrams from blueprints and on-site surveys to present the installation capacity.
On our pricing page, we list solar panels at an estimated cost of 800,000 JPY to 1,200,000 JPY for 3-5 kW, and 1,200,000 JPY to 1,900,000 JPY for 6-10 kW. (These are just estimated amounts and can vary based on wiring length, scaffolding range, existing roofing materials, panel layout, etc.)
▶ Service Menu | Click here for costs related to Solar Panel Installation and Storage Battery Installation
Items to Confirm in the Estimate (Cost Verification)
When comparing estimates, it is common to compare different capacities and equipment by only 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 per panel (W), number of panels, 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. Storage Battery | Manufacturer, model number, capacity (kWh), range available during power outages (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 securing it (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, 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. Application | 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, confirm that the same scope 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, details and duration of manufacturer warranty and workmanship warranty. |
If the capacity differs, both the price and power generation will change. Kakeru Koumuten Co., Ltd. warmly welcomes competitive estimates, so if you bring estimates from other companies, we will explain the differences for each item!
Self-Estimate and Profit Simulation for Solar Power Generation
With the simulator above,
you can obtain an approximate estimate and a profit simulation up to 30 years!
If you know the total installation capacity of solar panels on the roof and the capacity of the storage battery, you can obtain an approximate estimate and profit simulation!
*The simulation results are approximate. Actual profits may vary based on assumptions such as electricity rates, self-consumption ratios, selling prices, and costs for equipment inspection or replacement.
Customer Voices
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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)!
Examples of Solar Panel Installation
| Work 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 Manufactured / Aluminum Catch Type Hardware |
| Fixing Method & Waterproofing Arrangement |
| Fixed by catching the horizontal metal roof with catch type hardware (Catch Method) |
| Price Range |
| 2,200,000 JPY～2,300,000 JPY *Due to the grant being provided, the actual burden amount is approximately 1,000,000 JPY Estimated recovery period for construction costs: about 8 to 9 years (self-consumption) *The grant amount and recovery estimate are based on the system and calculations at the time of construction and may differ under the current system. |
| Construction Period |
| Approximately 3 days |
| Completion Month |
| April 2025 |
| Inquiry Details |
| I am considering the installation of solar panels and storage batteries. I heard that grants are available, and I would like to know how much can be provided. |
Our Proposal
We visited to provide an estimate and created a layout diagram for the solar panels based on the drawings!
The layout diagram shows the arrangement of solar panels when placed on the roof.
Since we can also determine the installation capacity, it allows for power generation simulations and financial simulations.
We have also understood the expected amount of grants, so we explained this to the customer along with the estimate!
How to Choose a Solar Panel Installation Contractor in Suginami, Tokyo
There are many solar panel installation contractors available in Suginami Ward, Tokyo, and you may be unsure which contractor to choose.
Therefore, when requesting solar panel installation and battery installation work, let’s check the following four points.
● Knowledge of roofs as well as solar panels is abundant
● Confirm the existence of warranties and aftercare maintenance
● Obtain estimates from multiple contractors (three companies as a guideline)
● Check if they provide support for subsidy applications
By confirming the above four points, you will be able to choose a reliable contractor.
Knowledge of roofs as well as solar panels
Defective installation of solar panels can sometimes be caused by a lack of knowledge and verification regarding roofs and waterproofing.
While knowledge of solar panels is certainly important, understanding the roof and waterproofing at the installation site of the solar panels is also crucial.
⚠︎Examples of troubles caused by insufficient verification of roofs and waterproofing
・Solar panels were installed on a severely deteriorated roof, leading to leaks
・Solar panels were installed on a roof with a short lifespan, necessitating a renovation for removal and reinstallation within a few years
・Misjudging the type of waterproofing led to incorrect processing and resulted in leaks
and more
When installing solar panels, understanding the condition and type of the existing roof allows you to avoid unnecessary expenses and unexpected troubles.
▶ Go to “Roof Verification Before Installing Solar Panels” in this article
Confirm the existence of warranties and aftercare maintenance
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, exclusions, and cost conditions.
While the solar panels and battery itself come with a manufacturer’s warranty, also check for the existence of a workmanship warranty in case leaks occur after installation!
For contractors that offer a workmanship warranty, if leaks occur after installation, they may be able to address the issue under the warranty, provided it falls within the warranty period and conditions.
Additionally, some contractors offer after-sales service separate from the warranty, so be sure to check if the contractor you are considering has after-sales service.
Changes or damage on the roof may occur in areas that are not visible, so there is a possibility that customers may not notice them.
By conducting inspections of these hidden areas during after-sales maintenance, it becomes easier to detect abnormalities early, preventing major repairs or breakdowns!
Kakeru Koumuten Co., Ltd. provides a rain leak warranty as part of the workmanship warranty for solar panel installations. (The warranty for solar panel installations is 10 years, and depending on the condition of the roof before installation, a roof renovation may be required to provide the warranty.)
We also conduct after-sales maintenance and send out DM every year!
Please check the DM, and if you wish, we will visit for after-sales maintenance!
Obtain estimates from multiple contractors (3 companies as a guideline)
When requesting the installation of solar panels, be sure to obtain estimates from multiple contractors.
Even for the same manufacturer and the same construction content, costs may vary, and warranties and after-sales services may differ.
Additionally, obtaining multiple estimates makes it easier to negotiate prices.
To request services from your preferred contractor at a lower price, we recommend obtaining estimates from multiple contractors.
When comparing estimates, please check:
“Verification of estimate items”
“Type of solar panels”
“Warranties and after-sales services”
Carefully compare these details to 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
Subsidies may be available for solar panel installations and battery installations, but if the order of procedures is incorrect or if there are deficiencies in the documents, the subsidy may not be granted.
There are systems that require personal applications and cannot be handled by the contractor, as well as systems that require prior application before installation, so it is reassuring to have a contractor that supports the preparation of necessary documents and the flow of procedures.
Complete the procedures specified for each system (for Tokyo subsidies, prior application before installation; for Suginami Ward grants, application after construction and payment completion) before proceeding with the construction!
In the case of subsidies in Tokyo, the process involves submitting a grant application and performance report after the completion of the work, which will be granted after a review! (The procedure varies depending on the system)
▶ Go to “Subsidies and Grants That May Be Applicable in Suginami Ward” within this article
Benefits of Introducing Solar Power Equipment
The benefits of introducing solar panels are as follows!
Benefit 1: Economic Advantage
The biggest advantage of introducing solar panels is the economic benefit!
While the selling price of electricity has decreased compared to ten years ago, you can gain benefits by reducing the electricity purchased from the power company through self-consumption of generated electricity!
As electricity prices rise, the ability to cover consumption with solar power becomes attractive!
If you plan to use the generated electricity at night, the installation of a storage battery is essential!
Furthermore, the selling price (FIT) for residential use (under 10kW) will be set at “24 yen/kWh for the first four years, and 8.3 yen/kWh from the fifth to the tenth year” for certifications after October 2025, and the same price will apply in the 2026 fiscal year. After the fifth year, it is generally more advantageous to use it at home (self-consume) rather than selling it, making the combination with a storage battery a viable option.
👉 For purchase prices, periods, etc., visit the Agency for Natural Resources and Energy
Benefit 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!
The reduction of the actual burden amount through subsidies is a significant advantage!
In the case of Suginami Ward, in addition to national and Tokyo metropolitan systems, there is a possibility of being eligible for the Suginami Ward Eco Housing Promotion Subsidy (solar power generation systems and storage batteries) (the ward’s subsidy is applied for after the completion of the work and payment).
Benefit 3: Environmentally Friendly!
Solar power generation has low carbon dioxide emissions and can reduce dependence on fossil fuels, contributing to the mitigation of global warming.
Solar panels themselves do not produce noise or exhaust gases during the generation process, making them an environmentally friendly method of power generation. (However, devices such as power conditioners may have operational noise.)
Advantage 4 Expect heat insulation effects!!
By installing the panels on the roof or rooftop, they block direct sunlight to the roof.
Especially in summer, it can help reduce the temperature rise of the roof, so heat insulation effects are expected!
(Note: This does not improve the insulation performance of the building itself.)
Advantage 5 Electricity can be used even during power outages!!
If a storage battery is installed, it is possible to use electricity even during emergencies such as power outages!
Even without a storage battery, if you have a power conditioner with autonomous operation capability, you may be able to use electricity from a dedicated outlet during daytime generation.
(Note: The devices, output, and duration that can be used during a power outage vary depending on the model and wiring method.)
What points should be noted when introducing solar power generation?
Next, we will explain the “three points to note” when installing solar panels!
Point 1 Maintenance costs can be incurred
A particularly overlooked maintenance cost is for the roof where solar panels are installed.
If you perform roof renovations 10 to 20 years later, there will be costs for removing and reinstalling the solar panels.
If the existing roof is deteriorating, it is reassuring to renovate it with durable roofing materials before installing solar panels!
Additionally, there will be costs for regular inspections of the equipment, repairs or replacements of the power conditioner, and updates due to deterioration of the storage battery.
It would be reassuring to consider maintenance costs in simulations before introducing solar panels!
Point 2 The risk of leaks increases depending on the roofing material
The methods for securing slate roofs and tile roofs vary depending on the construction method, but when using screws or other fasteners to secure the roofing materials and substrate, waterproofing at the fastening points becomes crucial.
In methods that involve making holes in the roof, there is inevitably a risk of leaks.
Of course, we will ensure proper waterproofing, but if you are concerned about making holes, one option is to replace the roofing material with a metal roof and secure the solar panels using the catch method. (The catch method has compatibility conditions between the roofing material and the fasteners, and it cannot be used with all metal roofs.)
Catch-type base fastener for horizontal metal roofs
Note 3: The roof will become heavier
Since solar panels will be placed on the roof, it will become heavier. After investigating the existing roof, substrate, and load-bearing 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 widely.
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!
Choosing Method 1: Compare by Total Output of the Roof
When installing solar panels on the roof, it is important to consider how much electricity can be generated in the limited area, and the more electricity generated, the better!
Solar panels come in various sizes and outputs depending on the manufacturer.
For example, a 350W output panel and a 400W output panel may seem like the higher output panel is better at first glance.
However, if the size of the panel does not fit well with the roof, “20 panels of 350W can be installed, while only 15 panels of 400W can be installed,” leading to different possible installation numbers 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 a single panel is lower, the total output of the roof may be higher!
It is important to consider the total output of the roof rather than just the output of a single panel!
*The above calculations represent total output (kW). The actual electricity generation (kWh) will vary depending on conditions such as roof orientation, slope, and shading.
Choosing Method 2: Compare by Degradation Rate of Solar Panels
Solar panels have a degradation rate, and their output gradually decreases over 10 years and 20 years.
The degree of output reduction after long-term use varies by product. The manufacturer’s output guarantee value is a standard figure for warranty purposes and does not indicate the actual degradation rate or the amount of electricity generated.
Choosing solar panels while considering both the initial output and the degradation rate will lead to a decision without 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.
Some manufacturers offer a 30-year warranty for output, while others provide a 10-year warranty, so it varies widely!
A longer warranty is always better, so be sure to check the warranty period and conditions of the manufacturers you are considering!
Frequently Asked Questions about Solar and Storage Battery Installations in Suginami Ward
We have compiled frequently asked questions from customers considering the installation of solar panels and storage batteries in Suginami Ward. (Tap to open the answers)
How much does it cost to install solar panels and storage batteries in Suginami Ward, Tokyo?
The cost varies depending on the installation capacity, equipment, and roof condition. In the above construction example (solar panel 4.3kW + storage battery, completed in April 2025), it was 2.2 million yen to 2.3 million yen.
Guidelines 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 and storage battery installations in Suginami Ward?
As of October 7, 2026, Tokyo’s subsidies for solar power generation and storage batteries (Cool Net Tokyo) are accepting pre-applications. For storage batteries, only SII registered devices (registered products for Reiwa 8) are eligible from pre-applications made after October 1, 2026. The Suginami Ward Eco Housing Promotion Subsidy (40,000 yen per 1kW of solar power, maximum 120,000 yen; 50,000 yen for storage batteries) is accepting applications until February 26, 2027 (until the budget limit is reached). The national DR home 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 even after the construction is completed?
For many programs, procedures are required before construction. Tokyo’s subsidies require pre-application before installation, and if you install first, you will be ineligible. The Suginami Ward Eco Housing Promotion Subsidy allows applications after the completion of construction and payment, and pre-application is not necessary. Procedures differ by program.
Since the order of procedures varies by program, please confirm before signing a contract or starting construction.
Can solar panels be installed on slate roofs? I’m worried about leaks.
It is possible to install on slate roofs, but it is necessary to check the condition of the roofing material and substrate beforehand. The method of securing varies depending on the construction method, and when securing hardware to the roofing material or substrate, waterproof 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 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 10 to 20 years after installation, the cost of removing and reinstalling solar panels will be incurred separately. If the remaining lifespan of the roof is short, it may be more cost-effective to renovate to a highly durable roofing material before installation.
Please consult us on how to proceed with the installation after checking the condition of the roof during the on-site survey!
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 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 is designed for simultaneous installation with solar panels, but applications can also be made for storage batteries alone. You can compare “solar panels only” and “solar panels + storage battery” through a financial simulation.
How many kW can be installed on my roof? Is it okay for north-facing roofs or roofs with shadows?
The capacity that can be installed varies depending on the shape, orientation, and size of the roof. At Kakeru Koumuten Co., Ltd., we create a layout diagram from the drawings and on-site survey, and provide you with the installation capacity and power generation simulation.
Even in residential areas of Suginami Ward, the way shadows are cast by neighboring houses and surrounding buildings varies from one house to another. 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 roofing work is done simultaneously and the shape and installation capacity of the roof.
Please note that additional time is required for applications for subsidies and power companies, so please consult us as soon as possible.
What is the current selling price (FIT)?
For residential use (less than 10 kW), the rate for certifications after October 2025 will be 24 yen/kWh for the first 4 years, and 8.3 yen/kWh from the 5th to the 10th year, and the same price will apply in the 2026 fiscal year.
The idea is to recover initial costs more quickly in the first 4 years and then focus on self-consumption. Kakeru Koumuten Co., Ltd. provides a financial simulation that takes into account loan interest rates and electricity costs.
Can you provide maintenance and inspections after installation?
Yes, we can. Kakeru Koumuten Co., Ltd. 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 is reduced due to dirt.
The roof is a place that is difficult to check by yourself, so if you have any concerns, please feel free to consult us.
Can you also handle renovations for roofs that already have solar panels installed?
Yes, it is possible. Kakeru Koumuten Co., Ltd. can detach and reattach solar panels in-house, allowing us to remove the panels, perform roof overlay (cover method) or re-roofing, and then reinstall them consistently. The removed panels can be stored in our own warehouse.
For costs, please refer to the solar panel detachment and water heater removal pricing page.
If you are looking for a solar panel installation contractor in Suginami Ward, please consult Kakeru Koumuten
Our company handles a wide range of exterior renovations, including roof work and exterior wall work, in Suginami Ward, Tokyo, including solar panel installations.
We have received many requests from customers, including renovation companies and real estate companies, who have contacted us!
Kakeru Koumuten promises “high-quality renovations at low cost”, and we have received positive feedback from many customers.
We continue to update our construction performance each 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 work and re-roofing but also partial roof repairs, exterior wall 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 minimize costs”, “I just want an estimate for now”, we will provide optimal solutions for specific requests.
We will never propose unnecessary work that prioritizes profit!
We always stand in the customer’s position and propose the best construction plan!
We are confident that we will not be outdone in terms of cost, quality, and organization compared to other companies in exterior work!
We are confident, so we welcome competitive estimates!
Estimates are completely free, and if our company is found to be inferior to others, you are free to decline!
Characteristics of Suginami Ward, Tokyo, and Points for Solar Work
Suginami Ward, Tokyo, is located at the western edge of the 23 wards of Tokyo. The official page of Suginami Ward introduces it as being situated on the Musashino Plateau, with an area of 34.06 km2 and generally rectangular in shape. The terrain is generally flat, with the eastern part being slightly lower and gradually rising towards the west. The Zenpukuji River (central), Kanda River (southern), and Myōshōji River (northern) flow from west to east, and the areas along these river basins are slightly lower than the surroundings.
We have summarized the points to consider when installing solar panels and storage batteries in the residential environment of Suginami Ward. (Tap to open)
View the characteristics of Suginami Ward and points for solar work
■ In low-lying areas along rivers, check the installation location for storage batteries and power conditioners against flooding assumptions
While Suginami Ward is generally flat, the areas along the Zenpukuji River, Kanda River, and Myōshōji River are slightly lower than the surroundings. You can check the flooding assumptions for your residence on the ward’s flood hazard map. When deciding on the installation location for storage batteries and power conditioners, it is reassuring to check the flooding assumptions for your residence on the hazard map and consider the height and position of the installation.
■ Tokyo’s annual sunshine hours are approximately 1,927 hours
The Japan Meteorological Agency’s average values (1991–2020) indicate that Tokyo’s annual sunshine hours are approximately 1,927 hours.
Since power generation varies by season, it is important to conduct a year-round power generation simulation and choose the capacity of the storage battery to match the times when electricity is used the most.
■ In areas with closely spaced houses, check for shadows from neighboring houses and buildings
In places where houses are closely built, the shadows cast by neighboring houses and surrounding buildings vary for each house depending on the roof’s orientation and height. Since solar panels generate less power when shaded, Kakeru Koumuten Co., Ltd. creates layout diagrams based on blueprints and the actual site conditions, allowing you to confirm through power generation simulations.
■ In narrow roads of residential areas, plan scaffolding and equipment delivery carefully
In residential areas with narrow front roads, it may be necessary to devise plans for scaffolding and equipment delivery. Kakeru Koumuten Co., Ltd. will respond to the site using our own scaffolding team and scaffolding materials.
■ Check the roof condition according to the age of the building
For houses that have been built for many years, it is important to check the condition of the roofing materials and substrate before installing solar panels. Depending on the roof’s condition, installing them simultaneously with roof renovations can help reduce future costs for removing and reattaching solar panels.
■ Subsidies require prior application in Tokyo and post-construction application in Suginami Ward
In Tokyo, subsidies require prior application to Cool Net Tokyo before installation. Suginami Ward’s eco-home promotion subsidy must be applied for after the completion of construction and payment, and applications will close once the budget limit is reached. It is important to check the procedures and timelines for each system in advance, in conjunction with the timing of the construction.
Our company serves Kanagawa Prefecture and Tokyo, and we handle many exterior and solar construction projects in Suginami 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 for any sudden troubles!
Service Area in Suginami Ward, Tokyo
Kakeru Koumuten Co., Ltd. accepts requests for work in Kanagawa Prefecture and all areas of Tokyo.
List of Areas in Suginami Ward, Tokyo
Asagaya Minami, Suginami Ward / Asagaya Kita, Suginami Ward / Amanuma, Suginami Ward / Igusa, Suginami Ward / Izumi, Suginami Ward / Imagawa, Suginami Ward / Umezu, Suginami Ward / Eifuku, Suginami Ward / Omiya, Suginami Ward / Ogikubo, Suginami Ward / Kamiigusa, Suginami Ward / Kamiogi, Suginami Ward / Kamitakaido, Suginami Ward / Kogayama, Suginami Ward / Koenji Minami, Suginami Ward / Koenji Kita, Suginami Ward / Shimizu, Suginami Ward / Shimoigusa, Suginami Ward / Shimotakaido, Suginami Ward / Matsuan, Suginami Ward / Zenpukuji, Suginami Ward / Takaihodai, Suginami Ward / Takaihodai Nishi, Suginami Ward / Narita Higashi, Suginami Ward / Narita Nishi, Suginami Ward / Nishiogiminami, Suginami Ward / Nishiogikita, Suginami Ward / Hamadayama, Suginami Ward / Hounan, Suginami Ward / Horinouchi, Suginami Ward / Mottenuma, Suginami Ward / Matsunoki, Suginami Ward / Minamiogikubo, Suginami Ward / Miyamae, Suginami Ward / Momoi, Suginami Ward / Wada, Suginami Ward
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・Kakeru Koumuten Co., Ltd. project achievements
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・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 generation? Comprehensive tips to reduce costs!
・Where is the best place to install solar power generation? Key points for site selection included!
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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!
