Leave Your Solar Panel Installation Work in Katsushika, Tokyo to Kakeru Koumuten Co., Ltd.!
For solar panel and battery installation in
Katsushika, 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 and battery installation considering roofing and waterproofing!
“How to Choose a Solar Panel Contractor in Katsushika”
“Costs for Solar Panel and Battery Installation”
“Subsidies Available for Solar System Installation in Katsushika”
We will also explain the above three points!
Installing solar panels carries risks such as “the occurrence of leaks” and other troubles.
To ensure you have no regrets about your solar panel installation, we recommend obtaining around three estimates!
Table of Contents (tap to open/close)
- Reasons Why Kakeru Koumuten Is Chosen for Solar Panel Installation in Katsushika, Tokyo
- Roof Inspection Before Installing Solar Panels
- Possible Subsidies and Grants Available in Katsushika
- Pricing Table for Solar Panel and Storage Battery Installation
- Breakdown of Installation Capacity, Equipment, and Construction Costs
- Self-Estimate and Profit Simulation for Solar Power Generation
- Customer Testimonials
- Case Studies of Solar Panel Installations
- How to Choose a Solar Panel Installation Contractor in Katsushika, 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 Katsushika
- If You’re Looking for a Solar Panel Installation Contractor in Katsushika, Contact Kakeru Koumuten
- Characteristics of Katsushika, Tokyo and Key Points for Solar Installation
- Service Area in Katsushika, Tokyo
Reasons Why Kakeru Koumuten Is Chosen for Solar Panel Installation in Katsushika, Tokyo
Here are the reasons why our company is entrusted with solar panel installation by customers in Katsushika, Tokyo:
One reason is that “Kakeru Koumuten covers Kanagawa and Tokyo as its service areas”,
and we have “unique strengths in solar panel installation that cannot be imitated by other companies”, which has received high praise from many customers.
so we would appreciate it if you could compare our estimates with those of other companies.
Because we are confident, we welcome estimates from any number of companies!
1. We Also Handle Exterior Renovations Beyond Solar Panel Installation!
Problems such as leaks that occur during solar panel installation may be caused by insufficient checks on the roof and waterproofing at the installation site.
Even if you are knowledgeable about solar panels, there are cases where the roof and waterproofing at the installation site are outside your expertise, so caution is necessary.
It is reassuring to have expertise in roofing to avoid maintenance issues and troubles after installation!
Kakeru Koumuten Co., Ltd. is strong in roofing work and can also detach and attach solar panels in-house, allowing for quick responses to maintenance and urgent troubles after solar panel installation!
2.Facilities Specialized in Exterior Renovation
Kakeru Koumuten Co., Ltd. has organized the following warehouses and material storage areas to provide low-cost, high-quality solar work and exterior renovations.
We have established five bases centered around Yokohama City, Kanagawa Prefecture for material storage and showrooms.
In-house Scaffolding Materials
To ensure safety during work on the roof, we own the scaffolding materials necessary for temporary scaffolding according to construction conditions and can assemble scaffolding in-house.
By not outsourcing scaffolding work and using our own scaffolding team, we can also reduce the costs of scaffolding work.
We own scaffolding materials for approximately 50 single-family homes!
Even in Katsushika Ward, surrounded by rivers, our in-house scaffolding team will plan scaffolding according to the local conditions.
Storage of Materials in Our Large Warehouse
We store roofing materials and paints, and we can also store removed solar panels.
By ordering a large quantity of materials at once, you can purchase materials at a lower cost!
Additionally, we always have a stock of roofing materials, so we can respond quickly in emergencies!
In-house sorting and transportation of waste materials
The installation of solar panels often involves roofing work, generating various waste materials such as paint, wood, and metal.
By sorting and recycling waste materials, we can significantly cut waste disposal costs.
Exterior renovation dedicated showroom
In the showroom, not only can you have meetings, but you can also
check the actual foundation brackets for solar panels and see how they are attached to the roofing materials!
You can also simulate the potential earnings and costs associated with installing solar panels!
Since roofing and exterior wall work often accompany each other, we also provide samples of roofing materials and models that explain the structure, allowing for detailed explanations!
3.All work performed by our own team
One of Kakeru Koumuten’s major strengths is its complete in-house construction.
By having Kakeru Koumuten manage everything from inquiries to project completion in a consistent manner, we can keep costs down and provide high-quality roof renovations.
Additionally, one representative will handle everything from the estimate to the completion of the work.
Since the person in charge does not change, whether it’s the sales representative or the construction management staff, smooth communication is possible.
We can perform consistent in-house construction from temporary scaffolding installation, exterior wall painting, to roof renovations!
4. Various Permits and Skilled Workers
We have obtained construction industry licenses and permits for industrial waste collection and transportation!
We also have nationally certified sheet metal workers and painting technicians on staff, giving us confidence in our construction techniques.
We are capable of handling large-scale roof projects such as those for factories!
5. Warranty and Aftercare
In addition to the manufacturer’s warranty for solar panel installation work, we also provide our own construction warranty (leakage warranty)!
(The construction warranty for solar panel installation is 10 years. Depending on the condition of the roof before installation, we may not be able to provide a warranty unless roof renovations are performed. The construction warranty is separate from the manufacturer’s product warranty, and the scope and conditions vary depending on the warranty details.)
Aftercare is available every year, and we send out notification DM each year.
If you have questions about the warranty, please click on the image above!
6. Flexible and Prompt Response
Our company is equipped to handle various roofing troubles and situations.
Even if you cannot access the roof at high altitudes, we can utilize drones to assist!
During leak investigations, we can also conduct inspections using a thermal imaging camera.
If the power generation of your solar panels decreases due to dirt or other factors, we can provide cleaning services using specialized brushes.
We will respond according to your wishes.
7. Human Resource Development
To improve skills, we create various roofing models and conduct practical training.
Since the construction methods vary depending on the shape and slope of the roof, we regularly provide technical training to ensure that each staff member can handle various cases.
8. Creation of Easy-to-Understand Materials and Simulations
Kakeru Koumuten provides not only “estimates,” “layout diagrams,” and “power generation simulations” but also a “solar construction 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 projected cumulative profits and losses over 20 to 30 years.
Even customers who are not familiar with solar construction will receive materials that clearly outline points to consider and potential drawbacks!
We encourage you to obtain comparative estimates and compare them with other companies’ plans!
Roof Inspection Before Installing Solar Panels
Once solar panels are installed, they will remain on the roof for 20 to 30 years.
Confirming “Is it okay to install them directly on the current roof?” before installation is the key point to prevent leaks and unnecessary expenses!
Kakeru Koumuten, which specializes in roofing work, has summarized the items to check before installation.
| 1. Types of Roofing Materials and Age | The fixing method varies depending on the roofing material, such as slate, tiles, metal roofs, and flat roofs (roof waterproofing). If the remaining lifespan of the roofing material is short, we may suggest roof renovation first. |
| 2. Condition of Substrate and Waterproof Sheet | If the sheathing boards or roofing (waterproof sheet) under the roofing material are damaged, it will affect the fixing strength of the fittings and waterproofing. We will also check for any signs of leaks. |
| 3. Orientation, Slope, and Shadows of the Roof | The orientation and slope of the roof surface, as well as shadows from neighboring houses, trees, and utility poles, will affect the amount of power generated. We will create a layout diagram from the drawings and the site, and you can confirm it with a power generation simulation. |
| 4. Shape of the Roof and Usable Area | The number of panels (installation capacity) that can be placed depends on the shape and size of the roof. Since the number of panels that can be installed varies depending on the panel size, we will compare based on the total output of the roof. |
| 5. Fixing Method and Waterproofing Details | We will check whether the method involves drilling holes in the roofing material for fixing or using fittings to secure the roofing material. The fixing method varies by technique, so please confirm the waterproofing treatment of the fixing parts during the estimate. |
| 6. Weight of the Roof | The roof will become heavier due to the panels being added. After investigating the existing roof, substrate, and load-bearing capacity, replacing with lighter roofing materials may also be an option if necessary. |
| 7. Installation Location of Equipment and Wiring | We will confirm 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 Confirmation Points by Roofing Material
| Roof Material | Main Fixing Method | Pre-Installation Check Points |
|---|---|---|
| Slate Roof | Varies by method (e.g., fixing brackets to roof material and substrate with screws) | Waterproofing 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 involve fixing to the substrate) | Type and condition of tiles, substrate, load-bearing capacity. Depending on the investigation results, there may be a method to replace with lightweight roofing material before installation. |
| Metal Roof (Horizontal and Vertical) | Fixed with catch-type brackets that grip the roofing material (depends on the combination of roofing material and brackets) | Whether the roofing material and brackets are compatible, installation conditions from the roofing material manufacturer. If compatible, a method that does not drill holes may be available. |
| Flat Roof / Rooftop | Fixed by installing a frame | Type and deterioration status of the waterproof layer, waterproofing around the frame. Consider in conjunction with the timing of waterproofing work. |
If you perform roof renovations 10 to 20 years after installation, there will be additional costs for the removal and reinstallation of solar panels. If the roof is deteriorating, renovating to a highly durable roofing material before installation may help reduce costs in the long run.
Kakeru Koumuten Co., Ltd. specializes in roofing work and can also handle the removal and reinstallation of solar panels in-house, so please consult us according to the condition of your roof!
▶ Click here for roof renovations in Katsushika, Tokyo
Possible Subsidies and Grants in Katsushika, Tokyo
If you are introducing solar panels or storage batteries in Katsushika, Tokyo, there may be programs from the “National Government,” “Tokyo Metropolitan Government,” and “Katsushika Ward” that you can apply for.
The following information is based on the official pages of each program as of October 6, 2026. The application status may change due to budget and recruitment periods, 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 Generation Promotion Project” (Cool Net Tokyo) | New installation of certified solar modules in residential properties or their premises in Tokyo, 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 (up to 450,000 JPY), 120,000 JPY/kW for over 3.75kW New homes: 120,000 JPY/kW for 3.6kW or less (up to 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 Promotion Project” (Cool Net Tokyo) | New installation of storage batteries in residential properties in Tokyo, and must be SII registered equipment. This project is intended for simultaneous installation with solar power, but applications can be made for storage batteries only. Pre-applications after October 1, 2026 will only be eligible for SII registered products for Reiwa 8. | Storage battery package: 100,000 JPY/kWh (up to 1,200,000 JPY per household) Storage battery unit expansion: 60,000 JPY/kWh (up to 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 |
| Katsushika Ward “Reiwa 8 Year Katsushika Eco Subsidy (for Individual Homes)” | Residential properties where the applicant resides within the ward are eligible. Solar power generation systems, storage batteries, HEMS, V2H, etc., are eligible equipment. Pre-consultation is required at least 4 weeks before construction starts, and solar power systems that sell all generated electricity are not eligible. | Subsidy amounts are specified for each equipment (please check the official page of the ward for the subsidy amount and limits for Reiwa 8). | From April 1, 2026 to March 31, 2027 (must arrive by this date) Budget and application status are not listed on the ward’s official page, so please check with the Environmental Division. |
| 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 an initial effective capacity of 30,000 JPY per kWh (subsidy rate within 3/10; maximum of 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 equipment, but they must be combined with essential works such as insulation renovations for windows (openings) and the building structure; applications cannot be made for storage battery installation alone. Solar panels are not included as eligible equipment. | Storage battery: 96,000 JPY per household. | Ends as soon as the budget limit is reached. Please check the official site for application status. |
In Tokyo, a pre-application before installation is required for subsidies, and for the Katsushika Eco Subsidy in Katsushika Ward, pre-consultation is required at least 4 weeks before the start of construction. If construction begins beforehand, it may become ineligible, and applying does not guarantee approval. Procedures and eligibility for each program vary, so please confirm before contracting or starting work.
Kakeru Koumuten Co., Ltd. will guide you on eligibility conditions for each program after confirming them.
Tokyo “Reiwa 8 Year Household Solar Power Generation Promotion Project”
In Tokyo, through Cool Net Tokyo, subsidies are provided for those installing solar power generation systems in residential homes within the city. The target is systems using certified solar modules with a capacity of less than 50kW, newly installed in residential homes or their premises within the city. A pre-application before installation is required.
For existing homes, the subsidy amount is 150,000 JPY/kW for systems up to 3.75kW (maximum 450,000 JPY), and 120,000 JPY/kW for systems exceeding 3.75kW. Additionally, there are extra items for mounting frames, waterproofing work, and renovation defect insurance. Pre-applications will be accepted from May 29, 2026, and applications for grants and performance reports will be accepted from June 30, 2026, until 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 generation is here
Tokyo “Reiwa 8 Year Household Storage Battery Promotion Project”
Tokyo is also providing subsidies for newly installed storage batteries in residential homes within the city. The subsidy amount is 100,000 JPY per 1kWh of storage battery package (maximum 1,200,000 JPY per household), and for additional storage battery units, it is 60,000 JPY per 1kWh (maximum 720,000 JPY 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 products will be eligible. This project is intended for simultaneous installation with solar power, but applications can be made for storage batteries alone. Applications for grants and performance reports have been accepted since June 30, 2026.
👉 Cool Net Tokyo | Official page for storage batteries is here
Katsushika Ward “Reiwa 8 Year Katsushika Eco Subsidy (for individual residences)”
Katsushika Ward is implementing the “Katsushika Eco Subsidy,” which subsidizes the installation costs for solar power generation systems, storage batteries, HEMS, Ene-Farm, V2H, insulation renovations, etc., for residences where the applicant resides. A pre-consultation application must be submitted at least 4 weeks before the start of construction, and the application process is “pre-consultation application (document review and mailing of response) → construction → completion report.”
The solar power generation system has conditions such as the contractor and applicant being the same, and that systems selling all generated power are not eligible for subsidies. It is also a requirement that the same type of equipment has not received subsidies for the past 10 years in the same building. The application period is from April 1, 2026, to March 31, 2027 (must arrive by this date). For details on subsidy amounts, limits, budget status, and the possibility of combining with other subsidies, please check the district’s guidelines.
👉 Katsushika Ward Official Page (for individual residences) here
👉 Katsushika Ward | Solar Power Generation System Page here
National Subsidy “DR Home Storage Battery Project (Support Project for Home Storage System Introduction for DR Resource Implementation)”
The national government has been implementing the “DR Home Storage Battery Project” to support the installation of home storage batteries.
This program targets those who are newly introducing registered storage systems that can be utilized for demand response (DR), and for 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 also conditions such as being ineligible for items contracted or ordered before the grant decision.
However, the fiscal year 2025 supplementary budget reached its application amount on May 29, 2026, and the public recruitment has ended (the previous fiscal year 2024 supplementary budget also ended public recruitment on July 2, 2025). Applications are currently not possible, so please check the official site for future public recruitment.
Additionally, there are currently no subsidies confirmed for the installation of solar panels on existing homes.
👉 DR Home Storage Battery Project Official Site here
Solar Panel Installation & Storage Battery Installation Price List
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, measured in kWh (kilowatt-hours).
The amount of kW that can be placed on the roof varies for each house based on the roof’s shape, orientation, and size. At Kakeru Koumuten, we create layout diagrams from blueprints and on-site surveys to present the installation capacity.
On our pricing page, we list solar panel costs as approximately 800,000 JPY to 1,200,000 JPY for 3-5 kW, and 1,200,000 JPY to 1,900,000 JPY for 6-10 kW. (These are rough estimates and can vary based on wiring length, scaffolding range, existing roofing materials, panel layout, etc.)
▶ Service Menu | For costs related to solar panel installation and storage battery installation, click here
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 the estimates from each company!
| 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 with a battery. |
| 3. Storage Battery | Manufacturer, model number, capacity (kWh), range usable during a power outage (entire house or specific circuits), installation location. |
| 4. Mounting Frame and Hardware | Name of 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 the fixing 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-excluded, 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. welcome comparisons, 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 get 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 Feedback
-
customer reviews
Asao-ku, Kawasaki City | We received reviews about the ridge cap and rain gutter replacement work!
-
customer reviews
Kohoku-ku, Yokohama | We received reviews about the roof overlay (cover method)!
-
customer reviews
Kohoku-ku, Yokohama | We Received Reviews About Exterior Painting!
-
customer reviews
Hodogaya-ku, Yokohama | We received reviews about our exterior fence construction!
-
customer reviews
Tsurumi-ku, Yokohama | We received reviews about roof and exterior wall painting, as well as metalwork and rain gutter replacement work!
-
customer reviews
Higashiyamato City, Tokyo | We received reviews about exterior painting and roof overlay (cover method)!
Case Studies of Solar Panel Installations
| 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 using catch type hardware gripping the horizontal metal roof (Catch Method) |
| Price Range |
| 2,200,000 JPY～2,300,000 JPY *Due to the subsidy being granted, the actual burden amount is approximately 1,000,000 JPY Estimated recovery period for construction costs: about 8 to 9 years (self-consumption) *The subsidy 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 subsidies are available, and I would like to know how much will be granted. |
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 subsidies, so we explained this to the customer along with the estimate!
How to Choose a Solar Panel Installation Contractor in Katsushika, Tokyo
There are many solar panel installation contractors available in Katsushika, Tokyo, and you may be unsure which one to choose.
Therefore, when requesting solar panel installation and battery storage installation work, let’s confirm the following four 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 (three is a guideline)
● Check if they provide support for subsidy applications
By confirming the above four points, you will be able to choose a reliable contractor.
Knowledge about roofs as well as solar panels
Defective installation of solar panels can sometimes be caused by a lack of knowledge and verification regarding roofs and waterproofing.
While knowledge about solar panels is certainly important, understanding the roof and waterproofing at the installation site of the solar panels is also crucial.
⚠︎Examples of troubles caused by insufficient verification of roofs and waterproofing
・Solar panels were installed on a 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
・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 for installation that avoids unnecessary expenses and unforeseen troubles.
▶ Go to “Roof Verification Before Installing Solar Panels” in this article
Confirm the presence of warranties and after-sales maintenance
When choosing a solar installation contractor, let’s confirm the presence of warranties. It is important to check not only the duration of the warranty but also the coverage, exclusions, and cost conditions.
While the solar panels and battery storage units come with a manufacturer’s warranty, also check for the presence of a workmanship warranty in case leaks occur after installation!
For contractors that offer a workmanship warranty, if leaks occur after installation, they may be able to respond under the warranty, provided it is within the warranty period and conditions.
Additionally, some contractors offer after-sales service separate from warranties, so be sure to check if the contractor you are considering has after-sales service.
Since abnormalities or damage on the roof can occur in areas that are not visible, there is a possibility that customers may not notice them themselves.
By conducting inspections in after-sales maintenance, we can easily prevent major repairs or failures by discovering abnormalities early!
Kakeru Koumuten Co., Ltd. provides a leak warranty as part of the workmanship warranty for solar panel installations. (The warranty for solar panel installations is 10 years, and depending on the condition of the roof before installation, we may not be able to provide a warranty without performing roof renovations.)
We also conduct after-sales maintenance and send out annual DM!
Please check the DM, and if you wish, we will visit you for after-sales maintenance!
Obtain estimates from multiple contractors (3 companies as a guideline)
When requesting solar panel installation, 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 from your desired contractor at a lower price, we recommend obtaining estimates from multiple contractors.
When comparing estimates, please check
“Confirmation of estimate items”
“Type of solar panel”
“Warranties and after-sales services”
and make a detailed comparison! If the rank of auxiliary materials is low or if processes are skipped, costs can be reduced, so avoid making judgments based solely on price!
▶ Go to “Breakdown of Installation Capacity and Equipment/Construction Costs” in this article
Check if they provide support for subsidy applications
There may be subsidies available for solar panel 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.
Since there are systems that require personal applications and cannot be handled by the contractor, as well as systems that require prior applications before installation, 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) 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, followed by a review before the grant is awarded! (The procedure may vary depending on the system.)
▶ To “Subsidies and Grants that May Be Applicable in Katsushika Ward” within this article
Benefits of Introducing Solar Power Systems
The benefits of introducing solar panels are summarized in the following 5 points!
Benefit 1: Economic Benefits
The biggest advantage of introducing solar panels is the economic benefit!
While the selling price of electricity has decreased compared to 10 years ago, you can benefit by reducing the electricity you purchase from the utility by consuming the electricity you generate!
As electricity prices rise, the ability to cover your consumption with solar power becomes increasingly attractive!
If you plan to use the generated electricity at night, installing a storage battery is essential!
Furthermore, the selling price (FIT) for residential use (under 10kW) will be set at “24 yen/kWh for the first 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 likely to be more advantageous to use it in your home (self-consumption) rather than selling it, making the combination with a storage battery a viable option.
👉 Ministry of the Environment | For purchase prices and periods, 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 Katsushika Ward, in addition to national and Tokyo metropolitan programs, there is a possibility of being eligible for the Katsushika Eco Subsidy (prior consultation for the ward’s subsidy is required 4 weeks before the start of construction).
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 produce operational noise.)
Advantage 4 Expect Heat Shielding 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 shielding 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 the solar panels!
Additionally, there will be costs for regular inspections of the equipment, repairs or replacements of the power conditioner, and updates due to deterioration of the storage battery.
It is 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 depending on the construction method, but when using screws or other fasteners to secure the roofing material and substrate, waterproofing at the fixed points becomes crucial.
In methods that involve making holes in the roof, the risk of leaks inevitably arises.
Of course, we will ensure proper waterproofing, but if you are concerned about making holes, one option is to replace the roofing material itself 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!
How to Choose 1: Compare by Total Output of the Roof
When installing solar panels on the roof, it is important to consider how much power can be generated in a limited area, and the more power generated, the better!
Solar panels come in various sizes depending on the manufacturer, and their outputs differ.
For example, a 350W output panel and a 400W output panel may seem that the higher output panel is better at first glance.
However, if the size of the panels does not fit well 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 on the same roof can differ due to the size of the panels.
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 represent total output (kW). The actual power generation (kWh) will vary based on conditions such as roof orientation, slope, and shading.
How to Choose 2: Compare by Degradation Rate of Solar Panels
Solar panels have a degradation rate, and their output gradually decreases over 10 years and 20 years.
The degree of output reduction after long-term use varies by product. The manufacturer’s output warranty value is a benchmark for guarantees and does not indicate the actual degradation rate or the amount of electricity generated.
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 Years
There are several types of warranties for solar panels, including “output warranty,” “natural disaster warranty,” and “system warranty,” and the warranty years differ 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 years and conditions of the manufacturers you are considering!
Frequently Asked Questions about Solar Power and Storage Battery Installation in Katsushika City
We have compiled frequently asked questions from customers considering the installation of solar panels and storage batteries in Katsushika City. (Tap to open the answers)
How much does it cost to install solar panels and storage batteries in Katsushika City, Tokyo?
The cost varies depending on the installation capacity, equipment, and roof condition. In the above construction example (solar panel 4.3kW + storage battery, completed in April 2025), it was 2.2 million yen to 2.3 million yen.
Guidelines by capacity are available on the solar panel installation and storage battery installation pricing page. We will create a layout diagram from the drawings and on-site survey and provide a free estimate!
Are there any subsidies available for solar power and storage battery installation in Katsushika City?
As of October 6, 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 after October 1, 2026. The Katsushika Eco Subsidy in Katsushika City has an application period until March 31, 2027 (must arrive by this date), and prior consultation is required at least four weeks before the construction start date. The national DR home storage battery project has ended its public recruitment.
Since the acceptance 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 the Katsushika Eco Subsidy requires prior consultation at least four weeks before the construction start date, and if you install first, you may become ineligible. 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 fixing method varies depending on the construction method, and when fixing brackets to the roofing material or substrate, waterproof treatment of the fixed parts is crucial.
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 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 reattaching 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 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 you can also apply for just the storage battery. 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.
In Katsushika Ward, due to high population density and many adjacent houses, the shading from neighboring houses and 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?
For 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.
Additionally, please note that there will be a separate period for applying for subsidies and to the power company, so please consult us early.
What is the current selling price (FIT)?
For residential use (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 price applying for the 2026 fiscal year.
The idea is to recover the initial costs quickly in the first four years and focus on self-consumption thereafter. Kakeru Koumuten Co., Ltd. provides a financial simulation considering loan interest rates and electricity costs.
Can you handle maintenance and inspections after installation?
Yes, we can. Kakeru Koumuten Co., Ltd. sends out annual after-service maintenance DM notices and visits customers who wish to have inspections. We can also clean solar panels with a special brush if the power generation decreases 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 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 Katsushika City, please consult Kakeru Koumuten Co., Ltd.
Our company handles a wide range of exterior renovations, including solar panels, roof work, and exterior wall work in Katsushika City, Tokyo.
We have received requests from many customers, including renovation companies and real estate agencies, who have contacted us!
Kakeru Koumuten Co., Ltd. promises “high-quality renovations at low cost”, and we have received great feedback from many customers.
We continue to update our construction achievements every year and will strive to improve quality to satisfy even more customers in the future.
Our company can perform all exterior renovations, not only roof overlay 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 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 about recommended solar panels”, “I want to keep costs down as much as possible”, “I just want an estimate for now”, we will provide optimal solutions for 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 construction!
We are confident, so we welcome competitive quotes!
Estimates are completely free, and if our company is found to be inferior to others, you are free to decline!
Characteristics of Katsushika City, Tokyo, and Points of Solar Construction
Katsushika Ward, located in the northeastern part of Tokyo, is surrounded by rivers such as the Arakawa, Nakagawa, and Edogawa. The official page of Katsushika Ward introduces that to the east, it borders Matsudo City in Chiba Prefecture across the Edogawa River, to the west it borders Adachi Ward and Sumida Ward, to the south it borders Edogawa Ward, and to the north it borders Yashio City and Misato City in Saitama Prefecture across the Obakawa River, with an area of 34.80 km2 and a population density of about 13,600 people per km2 (as of April 1, Reiwa 8).
We have summarized the points to consider when installing solar panels and storage batteries in the residential environment of Katsushika Ward below. (Tap to open)
View the characteristics of Katsushika Ward and points for solar construction
■ In densely populated areas, check for shadows from neighboring houses and roof orientation
Katsushika Ward has a high population density, with many houses built closely together. The shadows cast by neighboring houses and buildings vary for each house depending on the roof orientation and height. Since solar panels generate less electricity when shaded, Kakeru Koumuten creates layout diagrams based on blueprints and site conditions, and we confirm this through power generation simulations.
■ Tokyo’s annual sunshine hours are approximately 1,927 hours
According to the Japan Meteorological Agency’s average values (1991-2020), Tokyo’s annual sunshine hours are about 1,927 hours.
Power generation varies by season, so it is important to conduct annual power generation simulations and select the capacity of storage batteries to match the times when electricity is used the most.
■ In areas surrounded by rivers, check the installation locations of storage batteries and power conditioners against flooding assumptions
Katsushika Ward is surrounded by the Arakawa, Nakagawa, and Edogawa rivers, and the ward’s flood hazard map explanation page indicates that there are areas where flooding is expected to persist due to low elevation. When deciding on the installation locations for storage batteries and power conditioners, it is reassuring to check the flooding assumptions for your residence on the hazard map.
■ In residential areas with narrow roads, plan scaffolding and equipment delivery carefully
In densely populated areas, the front roads may be narrow, requiring careful planning for scaffolding and equipment delivery. Kakeru Koumuten will respond to site conditions with our own scaffolding team and our own scaffolding materials.
■ Check the roof condition according to the age of the building
For houses that have been around 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 reinstalling solar panels.
■ Subsidies require separate prior procedures from Tokyo and Katsushika Ward
Tokyo’s subsidies require prior application to Cool Net Tokyo, and Katsushika Ward’s Katsushika Eco Subsidy requires prior consultation at least four weeks before the start of construction. It is important to confirm the procedures and conditions for each system in advance, along with the timing of the construction.
Our company serves Kanagawa Prefecture and Tokyo, and we handle many exterior and solar construction projects in Katsushika Ward.
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 Katsushika, Tokyo
Kakeru Koumuten Co., Ltd. accepts requests throughout Kanagawa Prefecture and all of Tokyo.
List of Areas in Katsushika, Tokyo
Aoto, Katsushika / Okudo, Katsushika / Ohanajaya, Katsushika / Kanamachi, Katsushika / Kanamachi Water Purification Plant, Katsushika / Kamakura, Katsushika / Kameari, Katsushika / Kosuge, Katsushika / Shibamata, Katsushika / Shiratori, Katsushika / Shinkoiwa, Katsushika / Takasago, Katsushika / Takaracho, Katsushika / Tateishi, Katsushika / Shinjuku, Katsushika / Nishi-Kameari, Katsushika / Nishi-Shinkoiwa, Katsushika / Nishi-Mizumoto, Katsushika / Higashi-Kanamachi, Katsushika / Higashi-Shinkoiwa, Katsushika / Higashi-Tateishi, Katsushika / Higashi-Horikiri, Katsushika / Higashi-Mizumoto, Katsushika / Higashi-Yotsugi, Katsushika / Hosoda, Katsushika / Horikiri, Katsushika / Mizumoto, Katsushika / Mizumoto Park, Katsushika / Minami-Mizumoto, Katsushika / Yotsugi, Katsushika
・Trust Kakeru Koumuten for exterior wall painting in Katsushika, Tokyo!
・Trust Kakeru Koumuten for roof renovations in Katsushika, Tokyo!
・Trust Kakeru Koumuten for exterior renovations in Katsushika, Tokyo!
・Kakeru Koumuten’s construction achievements
・Kakeru Koumuten’s aftercare services
・Kakeru Koumuten’s construction menu and price list
・Kakeru Koumuten’s staff blog and announcements
・Explaining the importance of getting multiple estimates and comparison points!
・Top 12 solar power generation manufacturers! Features and selection tips included!
・What are the installation costs for solar power generation? Tips to reduce costs thoroughly explained!
・What are the best locations for installing solar power generation? Points for selecting installation sites included!
・Check out our solar power generation estimates here!
We welcome inquiries via LINE as well◎
We are also updating our Instagram regularly◎Please follow us◎
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!
