Leave Your Solar Panel Installation in Itabashi, Tokyo to Kakeru Koumuten Co., Ltd.!
For
Solar Panel and Storage Battery Installation in
Itabashi, Tokyo, trust Kakeru Koumuten!
Kakeru Koumuten is a specialized exterior renovation company headquartered in Aoba Ward, Yokohama City.
As a company strong in roofing work, we are entrusted with solar panel installation and storage battery installation considering roofs and waterproofing!
“How to Choose a Solar Panel Contractor in Itabashi”
“Costs for Solar Panel and Storage Battery Installation”
“Subsidies Available for Solar System Installation in Itabashi”
We will also explain the above three points!
Installing solar panels comes with risks such as “the occurrence of leaks” and other troubles.
To avoid regrets, we recommend obtaining estimates from about three companies!
Table of Contents (Tap to Open/Close)
- Reasons Why Kakeru Koumuten is Chosen for Solar Panel Installation in Itabashi, Tokyo
- Roof Inspection Before Installing Solar Panels
- Subsidies and Grants That May Be Available in Itabashi
- 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 Itabashi, 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 Itabashi
- If You Are Looking for a Solar Panel Installer in Itabashi, Contact Kakeru Koumuten
- Characteristics of Itabashi, Tokyo and Key Points for Solar Installation
- Service Area in Itabashi, Tokyo
Reasons Why Kakeru Koumuten is Chosen for Solar Panel Installation in Itabashi, Tokyo
Regarding why our company is entrusted with solar panel installation by customers in Itabashi, Tokyo,
One reason is that “Kakeru Koumuten covers Kanagawa and Tokyo as its service areas.” However,
“We have unique strengths in solar panel installation that cannot be imitated by other companies,” which has received high praise from many customers.
We would appreciate it if you could compare our estimates with those of other companies.
Because we are confident, we welcome inquiries for 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 be knowledgeable 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 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 centered around 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 and can assemble scaffolding ourselves.
By performing scaffolding work with our own scaffolding team instead of outsourcing, we can also reduce scaffolding construction costs.
We have scaffolding materials for approximately 50 detached houses!
Even in Itabashi Ward, where plateaus and lowlands spread, our own scaffolding team plans 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, we always have stock of roofing materials, so we canrespond quickly in emergencies!
Sorting and transporting waste materials in-house
The installation of solar panels often involves roofing work, generating various waste materials such as paint, wood, and metal.
By sorting and recycling waste materials, we can significantly cut waste disposal costs.
Exterior 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 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 have 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 renovations at reduced costs.
Additionally, one representative will handle everything from the estimate to project completion.
Since the same person will be in charge, whether it’s sales or construction management, smooth communication is possible.
We can perform consistent in-house work from temporary scaffolding installation to exterior wall painting and roof renovation!
4. Various Permits and Skilled Workers
We have obtained construction industry permits and permits for industrial waste collection and transportation!
We also have nationally certified sheet metal workers and painting technicians, and we are confident in our construction skills.
We can also handle large-scale roofing work for factories and other facilities!
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, we may not be able to provide a warranty unless roof renovation is performed. The workmanship warranty is separate from the manufacturer’s product warranty, and the scope and conditions vary based on the warranty details.)
Aftercare maintenance is available annually, and we send out notification DM every year.
If you have questions about the warranty, please click on the image above!
6. Flexible and Prompt Response
Our company is equipped to handle various roof troubles and situations.
Even if we 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 perform cleaning with a specialized brush.
We will respond according to the customer’s wishes.
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 to ensure that each staff member can handle various cases.
8. Creation of Clear 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 “profit and loss simulation” that takes into account loan interest rates and electricity costs.
The profit and loss simulation can be created for an estimated cumulative profit and loss 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 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 “whether it is 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. Type of roofing material and age | The method of securing 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 substrate and waterproof sheet | If the sheathing or roofing (waterproof sheet) beneath the roofing material is damaged, it will affect the fastening strength and waterproofing. We will also check for 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 power generation. We will create a layout diagram from the drawings and the site, and you can confirm it with the power generation simulation. |
| 4. Shape of the roof and available installation area | The number of panels (installation capacity) that can be placed depends on the shape and size of the roof. The number of panels that can be installed varies depending on the size of the panels, so we will compare based on the total output of the roof. |
| 5. Fixing method and waterproofing details | We will confirm whether the method involves drilling holes in the roofing material for fastening or using brackets to secure the roofing material. The fixing method varies by technique, so please check the waterproofing treatment of the fixed parts during the estimate. |
| 6. Weight of the roof | The roof will become heavier due to the added panels. After investigating the existing roof, substrate, and load-bearing capacity, replacing with lighter roofing materials may also be an option if necessary. |
| 7. Location of equipment installation 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 costs. |
Fixing Methods and Checkpoints by Roofing Material
| Roof Material | Main Fixing Method | Pre-Installation Check Points |
|---|---|---|
| Slate Roof | Varies by method (e.g., fixing brackets to the roof material and substrate with screws) | Waterproof treatment of fixing parts, cracks or deterioration of slate, condition of the substrate. If deterioration is significant, consider roof overlay (cover method) or replacement first. |
| Tile Roof | Fixed with brackets and methods suitable for the type of tile (even methods that do not drill holes in the tiles will fix to the substrate) | Type and condition of tiles, substrate, load-bearing capacity. Depending on the investigation results, there may be 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 Itabashi, Tokyo
PossibleSubsidies and Grants in Itabashi, Tokyo
If you are introducing solar panels or storage batteries in Itabashi, Tokyo, there may be programs from the “National Government,” “Tokyo Metropolitan Government,” and “Itabashi City” that you can apply for.
The following information is based on the official pages of each program 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 “Reiwa 8 Year Household Solar Power Introduction Promotion Project” (Cool Net Tokyo) | A system under 50kW with newly installed certified solar modules on residential properties within Tokyo. 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 “Reiwa 8 Year Household Storage Battery Introduction Promotion Project” (Cool Net Tokyo) | Newly installed storage batteries in residential properties within Tokyo, must be 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 |
| Itabashi Ward “Reiwa 8 Year Energy Saving & Renewable Energy Equipment Introduction Points (Itabashi Eco Points Project)” | Individuals with an address in the ward who install solar power systems in their own homes are eligible. Approval of the Tokyo subsidy project and confirmation of the subsidy amount is required, and an application to Tokyo is necessary before installation. Storage batteries are not eligible. | Solar power generation: 20,000 points/kW (maximum 80,000 points) 1 point can be used as 1 JPY through Itabashi Pay. |
First phase: October 1, 2026 to November 20, 2026 Second phase: December 1, 2026 to January 20, 2027 (Deadline may occur within the period if the budget limit is reached. Points can be claimed until March 10, 2027) |
| National “DR Household Storage Battery Project” (Reiwa 7 Year Supplement) | Newly introduced 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 30% and maximum 600,000 JPY per application). | The budget was reached on May 29, 2026, and the public recruitment has ended (applications are currently not accepted). |
| 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 renovation of windows (openings) and structures; applications cannot be made for storage battery installation alone. Solar panels are not included as eligible facilities. | Storage battery: 96,000 JPY per household | Ends once the budget limit is reached. Please check the official website for the status of applications. |
In Tokyo, a pre-application before installation is required for subsidies. For the Itabashi Eco Points (solar power) in Itabashi Ward, the application process is to apply after the subsidy amount from Tokyo has been confirmed. If construction begins beforehand, it may not be eligible for Tokyo’s subsidies, and applying does not guarantee approval. Procedures and eligibility for each program differ, so please confirm before contracting or starting construction.
Kakeru Koumuten will guide you on the eligibility conditions for each program after confirming them.
Tokyo “Reiwa 8 Year Household Solar Power Generation Promotion Project”
Tokyo is providing subsidies for those installing solar power generation systems in residential homes through Cool Net Tokyo. The target is systems using certified solar modules that are newly installed in residential homes or their premises, with a capacity of less than 50kW. A pre-application before installation is required.
For existing homes, the subsidy amount is 150,000 yen/kW for 3.75kW or less (maximum 450,000 yen), and 120,000 yen/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 subsidy and performance report is from June 30, 2026, to March 30, 2029. For details on eligible equipment and conditions, as well as the budget status, please check the official page.
👉 Cool Net Tokyo | Official page for solar power generation
Tokyo “Reiwa 8 Year Household Storage Battery Promotion Project”
Tokyo is also providing subsidies for newly installed storage batteries in residential homes. The subsidy amount is 100,000 yen per 1kWh of storage battery package (maximum 1,200,000 yen per household), and for additional storage battery units, it is 60,000 yen per 1kWh (maximum 720,000 yen per household), with additional amounts for participation in DR demonstrations.
The target is equipment registered with SII (Environmental Collaboration Initiative). If applying for pre-application after October 1, 2026, only equipment listed in the Reiwa 8 year SII registered product list 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 subsidy and performance report has been accepted since June 30, 2026.
👉 Cool Net Tokyo | Official page for storage batteries
Itabashi Ward “Reiwa 8 Year Energy-Saving & Renewable Energy Equipment Points (Itabashi Eco Points Project)”
Itabashi Ward is implementing the “Itabashi Eco Points Project,” which grants points to individuals who install eligible energy-saving and renewable energy equipment in residential homes within the ward. For solar power generation systems, the condition is that the subsidy decision from Tokyo has been received and the subsidy amount has been confirmed, and a pre-application to Tokyo is required before installation.
The points awarded are 20,000 points/kW for solar power (up to 80,000 points), which can be used as 1 point equals 1 yen through Itabashi Pay. The eligible solar power systems are those for which the subsidy amount from Tokyo Metropolitan Government is confirmed between April 1, 2026, and December 31, 2026, and applications are accepted only electronically. The application periods are from October 1, 2026, to November 20, 2026, for the first phase, and from December 1, 2026, to January 20, 2027, for the second phase. Applications will close within the period if the budget limit is reached. Storage batteries are not eligible. It is stated that it can be used in conjunction with the Tokyo Metropolitan Government’s subsidy and within the range that does not exceed the equipment costs, so please check the official page of the ward for details.
👉 Here is the official page of Itabashi Ward (Itabashi Eco Point Project)
National Subsidy “DR Home Storage Battery Project (Support Project for Home Storage Systems for DR Resource Introduction)”
The national government has been implementing the “DR Home Storage Battery Project” to support the installation of home storage batteries.
This program targets those who are newly introducing registered storage systems that can be utilized for demand response (DR). In the fiscal year 2025 supplementary budget, the subsidy amount was 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 also conditions such as that contracts or orders made before the grant decision are not eligible.
However, the supplementary budget for fiscal year 2025 reached the budget limit on May 29, 2026, and the public recruitment has ended (the public recruitment for the previous fiscal year 2024 also ended on July 2, 2025). Applications are currently not possible, so please check the official site 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 Storage Battery Project
Solar Panel Installation & Storage Battery Installation Price List
⇧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 checked 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 depending on the roof shape, orientation, and size. At Kakeru Koumuten, we create layout diagrams from blueprints and on-site surveys to present the installation capacity.
On our pricing page, we list solar panels as approximately 800,000 JPY to 1,200,000 JPY for 3-5 kW, and 1,200,000 JPY to 1,900,000 JPY for 6-10 kW. (These are just approximate amounts and can vary based on wiring length, scaffold range, existing roofing materials, panel layout, etc.)
▶ Service Menu | Click here for costs related to Solar Panel Installation and Storage Battery Installation
Items to Check in the Estimate (Cost Verification)
When comparing estimates, it is 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 per panel (W), number of panels, total installation capacity (kW) should be listed. |
| 2. Power Conditioner | Manufacturer, model number, capacity, number of units, installation location (indoor/outdoor). Also check if it is a type that controls in conjunction with a storage battery. |
| 3. Storage Battery | Manufacturer, model number, capacity (kWh), range of use during power outages (whole house or specific circuits), installation location. |
| 4. Mounting Frame and Hardware | Name of hardware suitable for roofing materials and 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, 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 | Extent of support for applications to the power company, certification application for selling electricity (FIT), and subsidy applications. |
| 8. Scaffolding | Scope and quantity of scaffolding. If roof work and exterior painting are done simultaneously, check that the same scope and quantity are not counted twice. |
| 9. Removal and Disposal | Whether the removal of existing solar thermal water heaters and old panels, as well as disposal costs for waste materials, are included. |
| 10. Tax Classification and Warranty | Whether prices are tax-inclusive or 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 for up to 30 years!
If you know the total installation capacity of solar panels on the roof and the capacity of the storage battery, you can obtain an approximate estimate and profit simulation!
*The simulation results are approximate. Actual profits may vary based on assumptions such as electricity rates, self-consumption ratios, selling prices, and costs for equipment inspection and replacement.
Customer Feedback
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customer reviews
Asao-ku, Kawasaki City | We received reviews about the ridge cap and rain gutter replacement work!
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customer reviews
Kohoku-ku, Yokohama | We received reviews about the roof overlay (cover method)!
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customer reviews
Kohoku-ku, Yokohama | We Received Reviews About Exterior Painting!
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customer reviews
Hodogaya-ku, Yokohama | We received reviews about our exterior fence construction!
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customer reviews
Tsurumi-ku, Yokohama | We received reviews about roof and exterior wall painting, as well as metalwork and rain gutter replacement work!
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customer reviews
Higashiyamato City, Tokyo | We received reviews about exterior painting and roof overlay (cover method)!
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 class |
| Base Mounting Hardware Used |
| Niigata Manufactured / 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 Expected recovery period for construction costs: about 8 to 9 years (self-consumption) ※The grant amount and recovery estimate are based on the system and calculations at the time of construction, and may differ under the current system. |
| Construction Period |
| About 3 days |
| Completion Month |
| April 2025 |
| Inquiry Details |
| I am considering the introduction of solar panels and storage batteries. I heard that grants are available, and I would like to know how much will be provided. |
Our Proposal
We visited to provide an estimate and created a layout diagram for the solar panels from the drawings!
The layout diagram shows the arrangement of solar panels when placed on the roof.
Since we can also determine the installation capacity, it allows for power generation simulations and financial simulations.
We have also understood the expected amount of the grant, so we explained it to the customer along with the estimate!
How to Choose a Solar Panel Installation Contractor in Itabashi, Tokyo
There are many solar panel installation contractors available in Itabashi Ward, Tokyo, and you may be unsure which contractor to choose.
Therefore, when requesting solar panel installation and battery storage installation work, let’s check the following 4 points.
● Have extensive knowledge not only about solar panels but also about roofs
● Confirm the presence of warranties and after-sales maintenance
● Obtain estimates from multiple contractors (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.
Knowledge about roofs as well as solar panels
Defective installation of solar panels can sometimes be caused by a lack of knowledge and confirmation regarding roofs and waterproofing.
While knowledge about solar panels is certainly important, understanding the roof and waterproofing at the installation site of the solar panels is also crucial.
⚠︎Examples of troubles caused by insufficient checks on 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, requiring renovations to detach and reattach the solar panels within a few years
・Misjudgment of the type of waterproofing led to incorrect treatment and subsequent leaks
and more
When installing solar panels, understanding the condition and type of the existing roof allows you to avoid unnecessary expenses and unexpected troubles.
▶ Go to “Roof Check Before Installing Solar Panels” in this article
Confirm the presence of warranties and after-sales maintenance
When choosing a solar installation contractor, let’s check for the presence of warranties. It is important to confirm not only the number of years but also the scope of coverage, disclaimers, and cost conditions.
While the solar panels and battery storage units come with manufacturer warranties, also check for the presence of a workmanship warranty in case leaks occur after installation!
If the contractor offers a workmanship warranty, they may cover any leaks that occur after installation within the warranty period and conditions.
Additionally, some contractors offer after-service separate from the warranty, so be sure to check if the contractor you are considering has after-service.
Changes or damages 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 in after-maintenance, even in areas that are not visible, it becomes easier to detect abnormalities early and prevent 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 installation is 10 years, and depending on the condition of the roof before installation, we may not be able to provide a warranty without performing roof renovations.)
We also conduct after-maintenance and send out DM every year!
Please check the DM, and if you wish, we will visit for after-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-services may differ.
Additionally, obtaining multiple estimates makes it easier to negotiate prices.
To request from your desired contractor at a lower price, we recommend obtaining estimates from multiple contractors.
When comparing estimates,
“Check the items in the estimate”
“Type of solar panel”
“Warranties and after-services”
and make a detailed comparison to make your judgment! If the rank of auxiliary materials is low or if processes are skipped, costs can be reduced, so avoid making judgments based solely on costs!
▶ Go to “Breakdown of Installation Capacity, Equipment, and Construction Costs” in this article
Check if they provide support for subsidy applications
There may be subsidies available for solar panel installations and battery installations, but if the order of procedures is incorrect or if there are deficiencies in the documents, the subsidy may not be granted.
There are systems that require personal applications and cannot be applied for by the contractor, as well as systems that require prior applications 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’s subsidy, a prior application before installation; for Itabashi Ward’s points, application after the confirmation of Tokyo’s subsidy amount) 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 by system)
▶ To “Subsidies and Grants That May Be Applicable in Itabashi Ward” within this article
Benefits of Introducing Solar Power Equipment
The benefits of introducing solar panels are summarized in the following 5 points!
Benefit 1: Economic Benefits
The biggest benefit of introducing solar panels is the economic advantage!
Although the selling price of electricity has decreased compared to 10 years ago, by consuming the electricity generated for your own use, you can reduce the amount of electricity purchased from the utility company and gain benefits!
As electricity costs 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 4 years, and 8.3 yen/kWh from the 5th to the 10th year” for certifications after October 2025, and the same price will apply for the 2026 fiscal year. After the 5th year, it is often more advantageous to use it at home (self-consumption), making the combination with a storage battery a viable option.
👉 Ministry of the Environment | For purchase prices, periods, etc., click here
Benefit 2: You Can Utilize Subsidies!
The conditions and amounts of subsidies vary by prefecture and municipality, but if you meet the requirements, you may be able to utilize subsidies!
Reducing the actual burden amount through subsidies is a significant advantage!
In the case of Itabashi Ward, in addition to national and Tokyo metropolitan programs, there is a possibility that the Itabashi Eco Point Project (solar power generation system) may apply (the ward’s points will be applied for after the Tokyo metropolitan subsidy amount is confirmed).
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 from hitting the roof.
Especially in summer, it can help reduce the temperature rise of the roof, so heat insulation effects can be expected!
(Note that 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 that the devices, output, and duration that can be used during a power outage vary depending on the model and wiring method.)
What points should be noted when introducing solar power generation?
Next, we will explain the “three points to note” when installing solar panels!
Point 1 Maintenance costs can be incurred
A particularly overlooked maintenance cost is for the roof where 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 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 ask for a simulation that considers maintenance costs 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 by construction method, but when using screws and other fasteners to secure roofing materials and substrates, waterproofing treatment 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 thorough waterproofing treatment, 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 fasteners 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 based on total roof output
When installing solar panels on the roof, it is important to know how much power can be generated in a limited area, and the more power 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 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, while only 15 panels of 400W can be installed,” meaning that the number of panels that can be installed may differ even on the same roof due to the size difference.
400W×15 panels = 6kW (total output of the roof)
350W×20 panels = 7kW (total output of the roof)
As shown above, even if the output of a single panel is lower, the total output of the roof may be higher!
It is important to consider the total output of the roof rather than the output of a single panel!
*The above calculations are for total output (kW). The actual power generation (kWh) will vary depending on conditions such as roof orientation, slope, and shading.
Choosing Method 2: Compare based on the degradation rate of solar panels
Solar panels have a degradation rate, and their output gradually decreases over 10 and 20 years.
The degree of output reduction after long-term use varies by product. The manufacturer’s output guarantee value is a benchmark for warranty purposes and does not indicate the actual degradation rate or power generation amount.
Choosing solar panels while considering the degradation rate, not just the initial output, 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 Installation in Itabashi Ward
We have compiled frequently asked questions from customers considering the installation of solar panels and storage batteries in Itabashi Ward. (Tap to open the answers)
How much does it cost to install solar panels and storage batteries in Itabashi Ward, Tokyo?
The cost varies based on 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 our 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 installation in Itabashi 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 (products registered in Reiwa 8) are eligible from pre-applications made after October 1, 2026. The Itabashi Eco Point project (solar power generation system) has an application period for the first phase from October 1 to November 20, 2026, and the second phase from December 1, 2026, to January 20, 2027, with the condition that the subsidy amount from Tokyo is confirmed (storage batteries are not eligible for the ward). The national DR household storage battery project has ended its public recruitment.
Since the acceptance status may change, please refer to the subsidy and grant section and consult 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 excluded from eligibility. The points in Itabashi Ward will be applied for after the subsidy amount from Tokyo is confirmed. 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 a slate roof, but it is necessary to check the condition of the roofing material and substrate beforehand. The method of securing it varies depending on the construction method, and when securing hardware to the roofing material or substrate, waterproofing treatment of the fixed parts is essential.
Kakeru Koumuten Co., Ltd. is a specialist in exterior renovations with a strong focus on roofing work, so we will check the condition of the roof before installation and suggest methods such as roof overlay (cover method) or re-roofing if deterioration is advanced.
My roof is old. Should I do a roof renovation first?
It depends on the condition of the roof. If a roof renovation is needed 10 to 20 years after installation, the cost of removing and reinstalling solar panels will be incurred separately. If the remaining lifespan of the roof is short, it may be more cost-effective to renovate with durable roofing materials before installation.
Please consult us on how to proceed with the installation after checking the condition of the roof during the on-site survey!
Is it better to install a storage battery together with 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 at 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 Itabashi 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 if roofing work is done simultaneously or depending on the shape of the roof and installation capacity.
Please note that additional time is required for subsidies and applications to power companies, so please consult us as soon as possible.
What is the current selling price (FIT)?
For residential use (under 10 kW), from the certifications after October 2025, the first four years will be 24 yen/kWh, and from the fifth to the tenth year, it will be 8.3 yen/kWh, with the same prices applied in the 2026 fiscal year.
The idea is to recover initial costs more quickly in the first four years and focus on self-consumption thereafter. 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-service maintenance notices via direct mail and visits customers who request inspections. We can also clean solar panels using a special brush if the power generation is reduced due to dirt.
The roof is a part that is difficult to check by yourself, so please feel free to consult us if you have any concerns.
Can you also handle renovations for roofs that already have solar panels installed?
Yes, we can. Kakeru Koumuten 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 all in one go. The removed panels can be stored in our own warehouse.
For costs, please refer to the solar panel removal and hot water heater removal pricing page.
If you are looking for a solar panel installation contractor in Itabashi Ward, please consult Kakeru Koumuten
Our company handles a wide range of exterior renovations, including solar panels, roof work, and exterior wall work in Itabashi Ward, Tokyo.
We have received many requests from customers, including renovation companies and real estate agencies!
Kakeru Koumuten Co., Ltd. promises “high-quality renovations at low cost”, and we have received positive feedback from many customers.
We continue to update our construction performance 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 work 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 water leakage work, we may be able to provide emergency measures without setting up scaffolding, as long as safety can be ensured, so please consult us!
“I want to know about recommended solar panels”, “I want to keep costs down as much as possible”, “I just want an estimate for now”, we will provide 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 best construction plan!
We are confident that we will not lose 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 Itabashi Ward, Tokyo and Points of Solar Work
Itabashi Ward, Tokyo, is located in the northwestern part of the 23 wards of Tokyo. According to the official page of Itabashi Ward, its area is 32.22 km2, ranking 9th among the 23 wards. It consists of the Musashino Plateau and the alluvial lowlands of the Arakawa River, with the southern part being elevated and the northern part being low-lying. The elevation ranges from about 35 meters in higher areas (such as near the Tokumaru Substation) to about 2 meters in lower areas (at points between the Shinkawaguchi River and the Arakawa River).
We have summarized the points to consider when installing solar panels and storage batteries in the residential environment of Itabashi Ward below. (Tap to open)
View the characteristics of Itabashi Ward, Tokyo, and points for solar construction
■ In areas with plateaus and lowlands, check the installation locations for storage batteries and power conditioners against flood risk
Itabashi Ward has a significant elevation difference between the high plateau and the lowlands near the Arakawa and Shinkawaguchi rivers. The ward’s flood hazard map is based on the assumption of flooding from the Arakawa River (with a total rainfall of 632 mm over three days in the Arakawa basin). When deciding on the installation locations for storage batteries and power conditioners, it is advisable to check the flood risk for your residence on the hazard map and consider the height and position of the installation for peace of mind.
■ Tokyo’s annual sunshine duration is about 1,927 hours
According to the Japan Meteorological Agency’s average values (1991-2020), Tokyo’s annual sunshine duration is approximately 1,927 hours.
Since power generation varies by season, it is important to conduct annual power generation simulations and choose the capacity of storage batteries to match the times when electricity is used 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 residential areas with narrow roads, plan scaffolding and equipment delivery carefully
In densely built residential areas, the front road may be narrow, requiring careful planning for scaffolding and equipment delivery. Kakeru Koumuten Co., Ltd. will respond to site conditions with 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 several 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 reinstalling solar panels.
■ The subsidy process involves applying to Tokyo Metropolitan Government first, then to Itabashi Ward
To receive subsidies from Tokyo Metropolitan Government, a prior application to Cool Net Tokyo is required before installation. The Itabashi Eco Point Project in Itabashi Ward is applied for after the subsidy amount from Tokyo is confirmed. 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 construction and solar projects in Itabashi 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 urgent issues!
Service Area in Itabashi Ward, Tokyo
Kakeru Koumuten Co., Ltd. accepts requests for work in Kanagawa Prefecture and all areas of Tokyo.
List of Areas in Itabashi Ward, Tokyo
Aioi-cho, Itabashi Ward / Akatsuka, Itabashi Ward / Akatsuka Shinmachi, Itabashi Ward / Azusazawa, Itabashi Ward / Izumicho, Itabashi Ward / Itabashi, Itabashi Ward / Inaridai, Itabashi Ward / Ohara-cho, Itabashi Ward / Otaniguchi, Itabashi Ward / Otaniguchi Kamimachi, Itabashi Ward / Otaniguchi Kitamachi, Itabashi Ward / Ooyama Kanai-cho, Itabashi Ward / Ooyama Higashimachi, Itabashi Ward / Ooyama Nishimachi, Itabashi Ward / Ooyama-cho, Itabashi Ward / Kaga, Itabashi Ward / Kamitabashi, Itabashi Ward / Kumano-cho, Itabashi Ward / Komone, Itabashi Ward / Saiwaicho, Itabashi Ward / Sakae-cho, Itabashi Ward / Sakashita, Itabashi Ward / Sakuragawa, Itabashi Ward / Shimizu-cho, Itabashi Ward / Shimura, Itabashi Ward / Shinkawaguchi, Itabashi Ward / Daimon, Itabashi Ward / Takashimadaira, Itabashi Ward / Higashi Shinmachi, Itabashi Ward / Tokiwa-dai, Itabashi Ward / Tokumaru, Itabashi Ward / Nakaitabashi, Itabashi Ward / Nakajuku, Itabashi Ward / Nakadai, Itabashi Ward / Nakamaru-cho, Itabashi Ward / Narimasu, Itabashi Ward / Nishidai, Itabashi Ward / Hasune-cho, Itabashi Ward / Hasune, Itabashi Ward / Hikawa-cho, Itabashi Ward / Higashi Sakashita, Itabashi Ward / Higashiyama-cho, Itabashi Ward / Fujimicho, Itabashi Ward / Futaba-cho, Itabashi Ward / Funado, Itabashi Ward / Honmachi, Itabashi Ward / Maeno-cho, Itabashi Ward / Misono, Itabashi Ward / Minamimachi, Itabashi Ward / Minami Tokiwa-dai, Itabashi Ward / Miyamoto-cho, Itabashi Ward / Mukaihara, Itabashi Ward / Yamato-cho, Itabashi Ward / Yayoi-cho, Itabashi Ward / Yotsuba, Itabashi Ward / Wakaki, Itabashi Ward
・Leave your exterior wall painting in Itabashi, Tokyo to Kakeru Koumuten Co., Ltd.!
・Leave your roof renovation in Itabashi, Tokyo to Kakeru Koumuten Co., Ltd.!
・Leave your exterior renovation in Itabashi, Tokyo to Kakeru Koumuten Co., Ltd.!
・Kakeru Koumuten Co., Ltd. construction achievements
・Kakeru Koumuten Co., Ltd. aftercare services
・Kakeru Koumuten Co., Ltd. construction menu and price list
・Kakeru Koumuten Co., Ltd. staff blog and announcements
・Explaining the importance of comparison estimates and key points!
・Top 12 solar power generation manufacturers! Features and selection tips included!
・What are the installation costs for solar power generation? Comprehensive tips to reduce costs!
・What are the best locations for solar power generation installation? Key points for site selection included!
・Here for solar power generation estimates!
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contact Kakeru Koumuten Co., Ltd.
Kakeru Koumuten is a young company whose team is, on average, in their late twenties, but our skills are second to none.
Our greatest strength is that we handle scaffolding, roofing and painting entirely in-house. In an industry where these tasks are usually divided among contractors, our complete service simplifies project management and helps keep costs down. Above all, if a problem arises, we respond promptly.
We proudly describe ourselves as the youngest and most helpful renovation company in Kanagawa!
