Leave Your Solar Panel Installation Work in Chuo City, Tokyo to Kakeru Koumuten Co., Ltd.!
For solar panel and battery installation in
Chuo Ward, Tokyo,
trust Kakeru Koumuten!
Kakeru Koumuten is a company specializing in exterior renovations.
As a company strong in roofing work, we are entrusted withsolar panel installation and battery installation considering roofing and waterproofing!
“How to Choose a Solar Panel Contractor in Chuo Ward, Tokyo”
“Costs for Solar Panel and Battery Installation”
“Subsidies Available for Solar System Installation in Chuo Ward, Tokyo”
We will also explain the above three points!
Installing solar panels carries risks, such as“the occurrence of leaks” and other troubles.
To ensure you have no regrets about your solar panel installation, we recommend obtainingestimates from about three companies!
Table of Contents (tap to open/close)
- Reasons Why Kakeru Koumuten is Chosen for Solar Panel Installation in Chuo City, Tokyo
- Roof Inspection Before Installing Solar Panels
- Subsidies and Grants That May Be Applicable in Chuo City, Tokyo
- Price List for Solar Panel and Storage Battery Installation
- Breakdown of Installation Capacity, Equipment, and Construction Costs
- Self-Estimate and Profit Simulation for Solar Power Generation
- Customer Testimonials
- Case Studies of Solar Panel Installations
- How to Choose a Solar Panel Installer in Chuo City, Tokyo
- Benefits of Introducing Solar Equipment
- Points to Note When Introducing Solar Power Generation
- How to Choose Solar Panels
- Frequently Asked Questions About Solar and Storage Battery Installation in Chuo City, Tokyo
- If You Are Looking for a Solar Panel Installer in Chuo City, Tokyo, Contact Kakeru Koumuten
- Characteristics of Chuo City, Tokyo and Points for Solar Installation
- Service Area in Chuo City, Tokyo
Reasons Why Kakeru Koumuten is Chosen for Solar Panel Installation in Chuo City, Tokyo
Regarding why we are entrusted with solar panel installation by customers in Chuo City, Tokyo,
“Our Unique Strengths in Solar Panel Installation That Cannot Be Imitated by Other Companies”
have received high praise from many customers.
so we would 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 with solar panel installation may be caused by insufficient checks on the roof and waterproofing at the installation site.
Even if one is knowledgeable about solar panels, there are cases where the roof and waterproofing at the installation site are outside their expertise, so caution is necessary.
It is reassuring to have a good understanding of the roof to avoid maintenance and problems after installation!
Kakeru Koumuten is strong in roofing work and can also detach and attach solar panels in-house, allowing for quick responses to maintenance and urgent problems after solar panel installation!
2.Facilities Specialized in Exterior Renovation
Kakeru Koumuten has prepared the following warehouses and material storage areas to provide low-cost, high-quality solar work and exterior renovations.
We have established five bases for material storage and showrooms.
In-house Ownership of Scaffolding Materials
To ensure safety during work on the roof, we own the scaffolding materials necessary for temporary scaffolding according to the construction conditions and can assemble scaffolding in-house.
By not outsourcing scaffolding work and using our own scaffolding team, we can also cut costs for scaffolding work.
We own scaffolding materials for approximately 50 houses!
Even if there are height differences on the site, our in-house scaffolding team will plan the scaffolding according to the local conditions.
Storage of Materials in Our Large Warehouse
We store roofing materials and paints, and we can also store removed solar panels.
By ordering a large quantity of materials at once, we canpurchase materials at a lower cost!
Additionally, we always have a stock of roofing materials, allowing us torespond quickly in emergencies!
Sorting and Transporting Waste Materials In-House
The installation of solar panels often involves roofing work, generating various waste materials such as paint, wood, and metal.
By sorting and recycling waste materials, we can significantly cut waste disposal costs.
Exterior Remodeling Dedicated Showroom
In the showroom, not only can you have meetings, but you can also
check the actual foundation brackets for solar panels and how they are installed on roofing materials!
We can also provide simulations of potential earnings and installation costs when introducing solar panels!
Since roofing and exterior wall work often accompany each other, we also have samples of roofing materials and models that explain the structure, allowing for detailed explanations!
3.All Work Performed by Our Own Team
One of Kakeru Koumuten’s major strengths is its complete in-house construction.
By having a consistent system from inquiry to project completion, Kakeru Koumuten can 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 manage the sales and construction oversight, smooth communication is possible.
We can provide consistent in-house construction from temporary scaffolding installation, exterior wall painting, to roof renovations!
4. Various Permits Obtained & Skilled Workers on Staff
We have obtained permits for construction work and industrial waste collection and transportation!
We also have nationally certified sheet metal workers and painting specialists on staff, giving us confidence in our construction techniques.
We can also handle large-scale roof projects for factories and other facilities!
5. Warranty and Aftercare Maintenance
In addition to the manufacturer’s warranty for solar panel installation, we also provide our own construction warranty (leakage warranty)!
(The construction warranty for solar panel installation is 10 years. Depending on the condition of the roof before installation, we may not be able to provide a warranty without performing roof renovations. The construction warranty is separate from the manufacturer’s product warranty, and the coverage and conditions vary based on the warranty details.)
Aftercare maintenance is available annually, and we send out notification DM each year.
If you have questions about the warranty, please click on the image above!
6. Flexible and Prompt Response
Our company is equipped to handle various roofing troubles and situations.
If you cannot access the roof at high altitudes, we can utilize a drone to assist!
During leak investigations, we can also conduct surveys using a thermal imaging camera.
If the power generation of solar panels decreases due to dirt, we can also provide 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 so 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.
For customers who are not familiar with solar construction, we compile easy-to-understand materials that include points to note and disadvantages!
We encourage you to obtain comparative estimates and compare them with other companies’ plans!
Roof Inspection Before Installing Solar Panels
Once solar panels are installed, they will remain on the roof for 20 or 30 years.
Confirming “Is it okay to install directly on the current roof?” before installation is the key point to prevent leaks and unnecessary expenses!
Kakeru Koumuten, which specializes in roofing work, has summarized the items to check before installation.
| 1. Types of Roofing Materials and Age | The fixing method varies depending on the roofing material, such as slate, tiles, metal roofs, and flat roofs (rooftop waterproofing). If the remaining lifespan of the roofing material is short, we may suggest roof renovation first. |
| 2. Condition of Substrate and Waterproof Sheet | If the sheathing or roofing (waterproof sheet) under the roofing material is damaged, it will affect the fastening strength and waterproofing. We will also check for any signs of leaks. |
| 3. Orientation, Slope, and Shadows of the Roof | The orientation and slope of the roof surface, as well as shadows from neighboring houses, trees, and utility poles, will affect the power generation. We can create a layout diagram from the drawings and the site, and you can check it with a power generation simulation. |
| 4. Shape of the Roof and Usable Area | The shape and size of the roof determine the number of panels that can be installed (installation capacity). The number of panels that can be installed varies depending on the panel size, 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 method for the fixing parts during the estimate. |
| 6. Weight of the Roof | The roof will become heavier due to the panels being installed. After investigating the existing roof, substrate, and load-bearing capacity, switching to lighter roofing materials may also be an option if necessary. |
| 7. Installation Location of Equipment and Wiring | We will check the installation location of the power conditioner and storage battery, as well as the wiring route to the distribution board. The length of the wiring will also affect the cost. |
| 8. Ease of Scaffolding Setup and Delivery Routes | If there is a height difference on the site, planning for scaffolding and the delivery routes for equipment and materials may require some ingenuity. We will also check the width of the front road and any steps on the site during the on-site survey. |
Fixing Methods and Checkpoints by Roofing Material
| Roof Material | Main Fixing Method | Pre-Installation Check Points |
|---|---|---|
| Slate Roof | Varies by method (methods such as fixing brackets with screws to the roofing material and substrate) | Waterproof treatment of fixing parts, cracks and deterioration of slate, condition of the substrate. If deterioration is advanced, consider roof overlay (cover method) or replacement first. |
| Tile Roof | Fixed with brackets and methods suitable for the type of tile (even methods that do not drill holes in the tiles will fix to the substrate) | Type and condition of tiles, substrate, load-bearing capacity. Depending on the investigation results, there may be methods to replace with lightweight roofing materials 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, 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 perform roof renovations 10 to 20 years after installation, there will be additional costs for removing and re-installing solar panels. If the roof is deteriorating, it may be more cost-effective in the long run to renovate to a highly durable roofing material before installation.
Kakeru Koumuten Co., Ltd. specializes in roofing work and can also handle the removal and re-installation of solar panels in-house, so please consult us according to the condition of your roof!
▶ Click here for roof renovations in Chuo City, Tokyo
Possible Subsidies and Grants in Chuo City, Tokyo
If you are introducing solar panels or storage batteries in Chuo City, Tokyo, there is a possibility that the systems from the “National Government,” “Tokyo Metropolitan Government,” and your local “Chuo City” may apply.
The following is based on information confirmed on the official pages of each system as of October 7, 2026. The acceptance status may change depending on the budget, so please check the latest information before contracting or starting work.
Eligibility Conditions and Application Period for Subsidy Programs
| Program | Main Eligibility Conditions | Subsidy Amount | Application Period & Status |
|---|---|---|---|
| Tokyo “Home Solar Power Generation Promotion Project” | Individuals, corporations, or management associations installing a new unused solar power system (output under 50kW, JET certification, etc.) in residential properties within Tokyo. The generated power must be used in the residential part. Pre-application is required | Existing homes: 15,000 JPY per kW for 3.75kW or less (maximum 450,000 JPY), 12,000 JPY/kW for over 3.75kW to under 50kW New homes: 12,000 JPY/kW for 3.6kW or less (maximum 360,000 JPY), 10,000 JPY/kW for over 3.6kW |
For the fiscal year 2026, pre-applications are being accepted from May 29 (will end when the budget is reached). From the pre-application for fiscal year 2026, submission of a certificate issued by a financial institution will be mandatory at the time of performance report. |
| Tokyo “Home Battery Installation Promotion Project” | Owners of eligible equipment (SII registered batteries) excluding national and local governments. Installation must occur between April 1, 2026, and March 30, 2027. If applying after October 1, 2026, only products registered with the national SII for fiscal year 2026 are eligible | Battery package: 100,000 JPY per kWh (maximum 1,200,000 JPY per household) Additional amount for participating in DR demonstration (100,000 JPY per unit; 150,000 JPY per unit if energy management equipment is installed) Battery unit expansion: 60,000 JPY/kWh (maximum 720,000 JPY per household) |
For the fiscal year 2026, pre-applications are being accepted from May 29. Grant application and performance report will start from June 30. |
| Chuo Ward “Subsidy for Introduction of Natural Energy and Energy-Saving Equipment for Residential and Multi-Family Housing” | Residents, owners of rental multi-family housing within the ward, small and medium-sized businesses, and management associations of condominium complexes within the ward. Installation and payment must be completed by March 15, 2027, with completion report by March 31. Pre-application is required about two weeks before construction | General: Solar power is 100,000 JPY per kW (maximum 350,000 JPY), battery systems are 10,000 JPY per kWh (maximum 100,000 JPY) Participants in “Chuo Eco Act” receive additional amounts (solar power is 150,000 JPY per kW, maximum 420,000 JPY; battery is 15,000 JPY per kWh, maximum 120,000 JPY) |
From April 1, 2026, will end when the budget is exhausted. As of September 30, 2026, the remaining budget ratio is 32.0%, and after reaching 20% remaining, only window applications will be accepted (updated October 5, 2026). |
| National “DR Home Battery Project” (Fiscal Year 2025 Supplement) | Newly introducing home battery systems that can be utilized for DR (demand response) with registered products. | Calculated based on a standard amount of 34,500 JPY per initial effective capacity of 1kWh (subsidy rate within 30% and maximum 600,000 JPY per application). | As of May 29, 2026, the budget has been reached, and the public recruitment has ended (the official site states there are no plans to reopen public recruitment, and applications are currently not possible). |
| National “Mirai Eco Housing 2026 Project” (Renovation) | 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 battery installation alone. Solar panels are not included as eligible facilities | Battery Storage: 96,000 JPY/unit | Ends once the budget limit is reached. As of October 5, 2026, the application amount for renovations is displayed as 8% of the budget on the official website. Please check the application status on the official site. |
The Tokyo solar power and battery storage subsidies require prior application. For battery storage applications made after October 1, 2026, only products registered with the national SII will be eligible, and the equipment requirements will change. The subsidy in Chuo Ward follows a prior application system that must be submitted about two weeks before construction, with work commencing after receiving the grant decision notification. Eligibility conditions, application procedures, and the possibility of combining with other subsidies vary by program, and applying does not guarantee a grant, so please confirm before contracting or starting work.
Kakeru Koumuten will provide guidance on eligibility conditions and application periods for each program after confirming them.
National Subsidy “DR Home Battery Storage Project (Support Project for Introducing Home Battery Systems for DR Resource Implementation)”
The national government has been implementing the “DR Home Battery Storage Project” to support the installation of home battery storage systems.
This program targets those who are newly introducing registered battery 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 JPY per 1 kWh of initial effective capacity, with a subsidy rate of up to 30% and a maximum of 600,000 JPY per application. There are conditions such as excluding contracts or orders made before the grant decision.
However, the fiscal year 2025 supplementary budget applications reached the budget limit on May 29, 2026, and the public offering has ended. The official site also states that there are no plans to reopen the public offering, and applications are currently not possible. Please check the official site for future public offerings.
Additionally, there are currently no subsidies confirmed for the installation of solar panels on existing homes.
👉 Click here for the DR Home Battery Storage Project official site
Tokyo “Promotion Project for Introducing Solar Power Generation in Homes”
This subsidy is for those installing unused solar power generation systems in residential homes within Tokyo. The simultaneous installation of battery storage is not a requirement.
●Existing Homes: For systems under 3.75 kW, 150,000 JPY per kW (maximum 450,000 JPY); for systems over 3.75 kW and under 50 kW, 120,000 JPY per kW.
●New Homes: For systems under 3.6 kW, 120,000 JPY per kW (maximum 360,000 JPY); for systems over 3.6 kW and under 50 kW, 100,000 JPY per kW.
●Additional amounts are available for the installation of rooftop structures and waterproofing work.
The target is for unused panels with an output of less than 50 kW that have obtained JET certification, installed in residential homes in Tokyo, and used in living spaces. The process involves making a prior application and then applying for the grant after installation. Starting from the fiscal year 2026 prior application, submission of a certificate issued by a financial institution will be mandatory at the time of performance reporting.
The official page of Tokyo states that pre-registration is being accepted from May 29, Reiwa 8. It will end as soon as the budget is reached, so please check the official page for the registration status.
👉 Here is the official page of Tokyo (Cool Net Tokyo)
Tokyo’s “Household Battery Introduction Promotion Project”
This is a subsidy for the installation costs of battery systems aimed at increasing self-consumption of electricity generated by solar power and improving energy independence during emergencies.
●Battery package: 100,000 JPY per kWh (up to 1,200,000 JPY per household)
●Additional for participating in DR demonstration: 100,000 JPY per unit (150,000 JPY per unit if energy management equipment is installed)
●Expansion of battery units: 60,000 JPY per kWh (up to 720,000 JPY per household)
Eligible applicants are owners of the subsidized equipment (excluding national and local governments), and installation must be completed between April 1, Reiwa 8 and March 30, Reiwa 11. If pre-registration is done after October 1, Reiwa 8, only products registered with the national SII for Reiwa 8 are eligible.
The official page of Tokyo states that pre-registration is being accepted from May 29, Reiwa 8. For detailed information such as conditions for combination with solar power generation, please check the official page.
👉 Here is the official page of Tokyo (Cool Net Tokyo)
Chuo Ward “Subsidy for Introduction of Natural Energy and Energy-Saving Equipment for Residential and Multi-Family Housing”
This is a subsidy for those who introduce solar power generation systems and battery systems to residential and multi-family housing within the ward. Before starting construction, pre-application must be made, and the process is to begin construction after receiving the grant decision notification. Eligible applicants include residents, owners of rental multi-family housing within the ward, small and medium-sized enterprises, and management associations of condominium units within the ward who bear the costs.
●Solar power generation system: 100,000 JPY per kW (up to 350,000 JPY)
●Battery system: 10,000 JPY per kWh of storage capacity (up to 100,000 JPY)
●Participants in “Chuo Eco Act” receive additional amounts (solar power is 150,000 JPY per kW, up to 420,000 JPY; battery is 15,000 JPY per kWh, up to 120,000 JPY)
Applications must be made about two weeks before the installation work, and installation and payment must be completed by March 15, Reiwa 9, with completion reports submitted by March 31, Reiwa 9. It is noted that if national and Tokyo subsidies are used in combination, the ward’s subsidy may be reduced.
The official page of Chuo Ward (updated October 5, Reiwa 8) states that applications will be accepted from April 1, Reiwa 8 until the budget is exhausted, and as of September 30, Reiwa 8, the remaining budget ratio is 32.0%. Once the remaining budget reaches 20%, applications will be limited to in-person submissions only. Since the application status may change, those considering applying should check the official page early.
👉 Here is the official page of Chuo Ward
Solar Panel Installation & Battery Installation Price List
⇧Service Menu | For Costs Related to Solar Panel Installation & Battery Installation, Click Here
⇧Service Menu | For Costs Related to Solar Panel Removal & Water Heater Removal, Click Here
Breakdown of Installation Capacity, Equipment, and Construction Costs
The costs for solar panels and batteries should be confirmed by separating them into “Equipment Costs (Device Costs)” and “Construction Costs.”
Even for the same “Complete Solar Panel Installation,” the amount can vary significantly depending on the installation capacity, equipment grade, and roof condition.
Considerations for Installation Capacity (kW) and Battery Capacity (kWh)
The installation capacity of solar panels is determined by “the output of one panel (W) × number of panels”, with the unit being kW (kilowatts). The amount of electricity that can be stored in batteries is compared using kWh (kilowatt-hours).
The amount of kW that can be placed on the roof varies for each house depending on the shape, orientation, and size of the roof. Kakeru Koumuten Co., Ltd. will create a layout diagram from the blueprints and on-site survey to present the installation capacity.
On our pricing page, we list solar panels as approximately 800,000 JPY to 1,200,000 JPY for 3 to 5 kW, and 1,200,000 JPY to 1,900,000 JPY for 6 to 10 kW. (These are just approximate amounts and may vary based on wiring length, scaffold range, existing roofing materials, panel layout, etc.)
▶ Installation Menu | Costs for Solar Panel Installation and Battery Installation
Items to Check in the Estimate (Cost Confirmation)
When comparing estimates, it is common to compare different capacities and equipment based solely on price. Please check if the following items are clearly stated in each company’s estimate!
| 1. Solar Panels | Manufacturer, model number, output of one panel (W), number of panels, total installation capacity (kW) are written. |
| 2. Power Conditioner | Manufacturer, model number, capacity, number of units, installation location (indoor/outdoor). Also check if it is a type that controls the battery together. |
| 3. Battery | Manufacturer, model number, capacity (kWh), range usable during a power outage (whole house or specific circuits), installation location. |
| 4. Mounting Frame and Hardware | Name of hardware suitable for roofing materials and method of securing (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 for fixed parts, whether necessary roof repairs and substrate reinforcements are included. |
| 7. Applications | How much support is included for applications to the power company, certification applications for selling electricity (FIT), and subsidy applications. |
| 8. Scaffolding | Scope and quantity of scaffolding. If it is simultaneous with roof work or exterior wall painting, check that the same scope and quantity are not double counted. |
| 9. Removal and Disposal | Whether the removal of existing solar thermal water heaters or old panels and disposal costs for waste materials are included. |
| 10. Tax Classification and Warranty | Whether it is tax-inclusive or tax-exclusive, conditions under which additional costs may arise, and details and duration of manufacturer and workmanship warranties. |
If the capacities differ, the amounts and power generation will also change. Kakeru Koumuten Co., Ltd. welcome comparisons, so if you bring estimates from other companies, we will explain the differences item by item!
Self-Estimate and Profit and Loss Simulator for Solar Power Generation
With the simulator above,
you can get an estimated quote and a financial simulation for up to 30 years!
If you know the total installation capacity of solar panels on the roof and the capacity of the storage battery, you can obtain an estimated quote and financial simulation!
*The simulation results are estimates. Actual financial results may vary based on assumptions such as electricity rates, self-consumption ratios, 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 Installations
| Construction Details |
| Solar Panel Installation Battery Installation |
| Existing Roofing Material |
| Horizontal Metal Roof (Super Galtect) |
| Installation Capacity |
| Solar Panel: 4.3kW Battery: 5kWh |
| Base Mounting Hardware Used |
| Niigata Manufacturing/Aluminum Catch Type Hardware |
| Fixing Method & Waterproofing Arrangement |
| Fixed using catch type hardware gripping the horizontal metal roof (Catch Method) |
| Price Range |
| 2,200,000 JPY～2,300,000 JPY *Due to the subsidy, 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 |
| About 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 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 it to the customer along with the estimate!
How to Choose a Solar Panel Installation Contractor in Chuo City, Tokyo
There are many solar panel installation contractors available in Chuo City, 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 existence of warranties and aftercare services
● Obtain estimates from multiple contractors (3 companies is a guideline)
● Check if they provide support for subsidy applications
By confirming the above 4 points, you will be able to choose a reliable contractor.
Have knowledge not only about solar panels but also about roofs
Improper installation of solar panels can 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, requiring a remodel to detach and reattach the solar panels within a few years
・Misjudgment of the type of waterproofing led to incorrect treatment, resulting in leaks
and more
When installing solar panels, understanding the condition and type of the existing roof allows you to avoid unnecessary expenses and unexpected troubles.
▶ Go to “Roof Verification Before Installing Solar Panels” in this article
Confirm the existence of warranties and aftercare services
When choosing a solar installation contractor, make sure to check for warranties. It is important to confirm 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 manufacturer warranties, also check for the existence of a workmanship warranty in case leaks occur after installation!
For contractors that offer workmanship warranties, if leaks occur after installation within the warranty period and conditions, they may cover the repairs under the warranty.
Additionally, some contractors provide aftercare services separate from warranties, so be sure to check if the contractor you are considering has aftercare services.
Since abnormalities or damage on the roof may not be visible, you might not notice them yourself.
By conducting inspections of hidden areas during aftercare maintenance, you can more easily detect abnormalities early and prevent major repairs or failures!
Kakeru Koumuten Co., Ltd. offers a rain leak guarantee as part of the workmanship warranty for solar panel installations. (The warranty for solar panel installations is 10 years, and depending on the condition of the roof before installation, we may not be able to provide a warranty unless roof renovations are performed.)
We also conduct aftercare maintenance and send out annual DM!
After confirming the DM, we will visit for aftercare maintenance if you wish!
Obtain estimates from multiple contractors (3 companies as a guideline)
When requesting solar panel installation, let’s obtain estimates from multiple contractors.
Even for the same manufacturer and the same work content, costs may vary, and warranties and after-sales services may differ.
Additionally, obtaining multiple estimates makes price negotiations easier.
To request your desired contractor at a lower price, we recommend obtaining estimates from multiple contractors.
When comparing estimates,
“Check the estimate items”
“Type of solar panels”
“Warranties and after-sales services”
let’s carefully compare and make a judgment! If the rank of auxiliary materials is low or if processes are skipped, costs can be reduced, so avoid judging solely based on price!
▶ Go to “Breakdown of installation capacity, equipment, and construction costs” within 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 like the Tokyo subsidy that require prior application, it is reassuring to have a contractor that supports the preparation of necessary documents and the flow of procedures.
Complete the procedures specified for each system (for the Tokyo subsidy, prior application is required) before proceeding with the construction!
For the Tokyo subsidy, after installation, you will need to submit a grant application and performance report, which will be reviewed before the grant is awarded! (The flow of procedures varies by system)
▶ Go to “Subsidies and grants that may be applicable in Chuo Ward, Tokyo” within this article
Benefits of Introducing Solar Equipment
The benefits of introducing solar panels are as follows!
Benefit 1: Economic Benefits
The biggest advantage of introducing solar panels is the economic benefit!
The selling price of electricity has decreased compared to ten years ago, but by consuming the electricity generated, you can reduce the amount of electricity purchased from the utility company and gain benefits!
As electricity costs rise, the ability to cover your consumption with solar power becomes attractive!
If you plan to use the generated electricity at night, installing a storage battery is essential!
Furthermore, the selling price (FIT) for residential use (under 10kW) will be set as “24 yen/kWh for the first four years, and 8.3 yen/kWh from the fifth to the tenth year” for certifications after October 2025, and the same price will apply for the 2026 fiscal year. After the fifth year, it is likely to be more advantageous to use it at home (self-consume) rather than sell it, making the combination with a storage battery a viable option.
👉 Ministry of the Environment and Energy | For purchase prices and periods, click here
Advantage 2 Subsidies can be utilized!
The conditions and amounts of subsidies vary by prefecture and municipality, but if you meet the conditions, you may be able to utilize subsidies!
The reduction of the actual burden amount through subsidies is a significant advantage!
In Chuo Ward, there is a possibility of being eligible for the national, Tokyo, and Chuo Ward systems. The Chuo Ward subsidy will end once the budget is exhausted, and as of September 30, Reiwa 8, the remaining budget ratio is reported to be 32.0% (please check the application status for each system).
Advantage 3 Environmentally friendly!
Solar power generation has low carbon dioxide emissions and can reduce dependence on fossil fuels, contributing to the mitigation of global warming.
Solar panels themselves do not produce noise or exhaust gases during the generation process, making them an environmentally friendly method of power generation. (However, devices such as power conditioners do have operational noise.)
Advantage 4 Heat insulation effects are expected!!
By installing them on the roof or rooftop, the panels block direct sunlight from hitting the roof.
Especially in summer, it can help reduce the temperature of the roof, providing expected heat insulation effects!
（This does not improve the insulation performance of the building itself）
Benefit 5 Electricity can be used even during power outages!!
If a storage battery is installed, it 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.
（The devices, output, and duration that can be used during a power outage vary depending on the model and wiring method）
What points should be noted when introducing solar power generation?
Next, we will explain the “three points to note” when installing solar panels!
Point 1 Maintenance costs can be incurred
A particularly overlooked maintenance cost is for the roof where solar panels are installed.
If you perform roof renovations 10 to 20 years later, there will be costs for removing and reinstalling the solar panels.
If the existing roof is deteriorating, it is reassuring to renovate it with durable roofing materials before installing solar panels!
Additionally, there will be costs for regular inspections of the equipment, repairs or replacements of the power conditioner, and updates due to the deterioration of the storage battery.
It would be reassuring to consider maintenance costs in simulations before introducing solar panels!
Point 2 The risk of leaks increases depending on the roofing material
The fixing methods for slate roofs and tile roofs vary by construction method, but in methods that fix hardware with screws to the roofing material or substrate, waterproofing of the fixed parts is crucial.
In methods that involve making holes in the roof, the risk of leaks inevitably occurs.
Of course, we will ensure proper waterproofing, but if you are concerned about making holes, replacing the roofing material with a metal roof and fixing the solar panels using the catch method is also an option. (The catch method has compatibility conditions between the roofing material and hardware, and it cannot be used with all metal roofs)
Catch-type base hardware for horizontal metal roofs
Note 3: The roof will become heavier
Since solar panels will be installed, the roof will become heavier. After investigating the existing roof, substrate, and load capacity, replacing with a lightweight roof may also be an option if necessary.
How to Choose Solar Panels?
There are many manufacturers of solar panels, and their output and costs vary.
It is not simply a matter of “this manufacturer has the best solar panels”; it is important to choose solar panels that are suitable for your life plan and building!
Here are some points to consider when comparing solar panels!
Choosing Method 1: Compare by Total Output of the Roof
When installing solar panels on the roof, it is important to know how much power can be generated in a limited area, and generating more power is always better!
Solar panels come in various sizes and outputs depending on the manufacturer.
A panel with an output of 350W and a panel with an output of 400W may seem that the higher output panel is better at first glance.
However, if the size of the panel does not fit well on the roof, “20 panels of 350W can be installed” and “15 panels of 400W can be installed,” meaning the number of panels that can be installed on the same roof may 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 one panel is lower, the total output of the roof may be higher!
It is important to consider the total output of the roof rather than the output of a single panel!
*The above is a calculation of total output (kW). The actual power generation amount (kWh) will vary depending on conditions such as roof orientation, slope, and shading.
Choosing Method 2: Compare by Degradation Rate of Solar Panels
Solar panels have a degradation rate, and their output gradually decreases after 10 years and 20 years.
The degree of output reduction after long-term use varies by product. The manufacturer’s output guarantee value is a standard figure for warranty purposes and does not indicate the actual degradation rate or power generation amount.
Choosing solar panels while considering the degradation rate will help avoid regrets!
Choosing Method 3: Compare by Warranty Period
There are several types of warranties for solar panels, including “output warranty,” “natural disaster warranty,” and “system warranty,” and the warranty periods vary by manufacturer.
For output warranties, some manufacturers offer a 30-year warranty while others provide a 10-year warranty, so it varies widely!
It’s always better to have a longer warranty, so let’s check the warranty periods and conditions of the manufacturers you are considering!
Frequently Asked Questions about Solar Power and Storage Battery Installation in Chuo City, Tokyo
We have compiled frequently asked questions from customers considering the installation of solar panels and storage batteries in Chuo City, Tokyo. (Tap to open the answers)
How much does it cost to install solar panels and storage batteries in Chuo 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 for different capacities 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 Chuo City, Tokyo?
As of October 7, 2026, Tokyo’s “Solar Power Generation Promotion Project for Households” (for existing homes, 15,000 yen per kW for systems under 3.75kW, with a maximum of 450,000 yen) and “Storage Battery Introduction Promotion Project for Households” (100,000 yen per kWh for storage batteries, with a maximum of 1.2 million yen per household) are accepting pre-applications starting May 29, 2026, as posted on the official Tokyo website (Cool Net Tokyo). In Chuo City, the subsidy for the introduction of renewable energy and energy-saving equipment for residential and multi-family housing (general application for solar power generation is 100,000 yen per kW with a maximum of 350,000 yen, and for storage systems, 10,000 yen per kWh with a maximum of 100,000 yen) is currently accepting applications until the budget runs out, as stated on the official Chuo City website. The national DR household storage battery project has ended its public recruitment.
Since the application status may change, please refer to the subsidy and grant section and consult with us before signing a contract.
Can I apply for subsidies after the construction is completed?
This depends on the system. The Tokyo subsidy requires a pre-application, and Chuo City’s subsidy also requires application about two weeks before construction. Conditions such as whether you can contract and start construction before applying vary by system, so please check before signing a contract.
The order of procedures varies by system, so please confirm before signing a contract and starting construction.
Can solar panels be installed on a slate roof? I’m worried about leaks.
It is possible to install on a slate roof, but it is necessary to check the condition of the roofing material and substrate. The method of securing the panels varies by construction method, and when securing brackets to the roofing material or substrate, waterproofing treatment of the fixed parts is essential.
Kakeru Koumuten Co., Ltd. is a specialized exterior renovation company strong in roofing work, so we will check the condition of the roof before installation. If deterioration is progressing, we can also propose methods such as roof overlay (cover method) or complete replacement before installation.
My roof is old. Should I do a roof renovation first?
It depends on the condition of the roof. If a roof renovation is needed after 10 to 20 years of installation, there will be additional costs for removing and reinstalling solar panels. If the remaining lifespan of the roof is short, it may be more cost-effective to renovate with durable roofing materials before installation.
Please consult us on how to proceed with the installation after confirming the condition of the roof through a site survey!
Should I install a storage battery together with the solar panels?
If you want to use the generated electricity at night or prepare for power outages, simultaneous installation is recommended. The selling price for electricity will be 8.3 yen/kWh after the fifth year, making it more advantageous to use it in your home rather than selling it.
Additionally, the subsidy for storage batteries in Tokyo (for Reiwa 8, it is 100,000 yen per kWh, with a maximum of 1,200,000 yen per household) aims to increase self-consumption of electricity generated by solar power. In Chuo Ward, storage systems are also included in the subsidy targets. You can compare “solar only” and “solar + storage battery” through a financial simulation.
How many kW can be installed on my roof? Is it okay for north-facing roofs or roofs with shadows?
The capacity that can be installed varies depending on the shape, orientation, and size of the roof. At Kakeru Koumuten, we create a layout diagram from the drawings and site survey, and provide you with the installation capacity and power generation simulation.
Chuo Ward is mostly a reclaimed land area from the Edo period, characterized by low and flat terrain. The shape and orientation of the roof, as well as the shadows cast by surrounding buildings, will differ from house to house. 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.
Please note that additional time is required for applications for subsidies and electric companies, so please consult us as soon as possible.
What is the current selling price (FIT)?
For residential use (under 10 kW), from the certification after October 2025, the first 4 years will be 24 yen/kWh, and from the 5th to the 10th year, it will be 8.3 yen/kWh, and the same price will apply in the 2026 fiscal year.
The idea is to recover initial costs more quickly in the first 4 years and then focus on self-consumption. Kakeru Koumuten provides a financial simulation that takes into account loan interest rates and electricity costs.
Can you handle maintenance and inspections after installation?
Yes, we can. Kakeru Koumuten sends out annual after-maintenance DM notices and visits for inspections upon request from customers. We can also clean solar panels with a special brush if the power generation decreases due to dirt.
It is difficult to check areas on the roof by yourself, so please feel free to consult us if you have any concerns.
Can you also renovate roofs that already have solar panels installed?
It is possible. Kakeru Koumuten Co., Ltd. can detach and reattach solar panels in-house, allowing us to perform roof overlay (cover method) or re-roofing after removing the panels, and we will handle everything consistently until reinstallation. The removed panels can be stored in our own warehouse.
For costs, please refer to the solar panel detachment and hot water heater removal pricing page.
If you are looking for a solar panel installation contractor in Chuo City, Tokyo, please consult Kakeru Koumuten
Our company handles many exterior renovations, including solar panels, roof work, and exterior wall work in Chuo City, Tokyo.
We receive requests from many customers, including renovation companies and real estate agencies!
Kakeru Koumuten promises “high-quality renovations at low cost”, and we have received great feedback from numerous customers.
We continue to update our construction achievements every year, and we will strive to improve quality to satisfy even more customers in the future.
Our company can perform all exterior renovations, not only roof overlay (cover method) and re-roofing but also partial roof repairs, exterior painting, and exterior wall cover methods.
We are also happy to handle small jobs such as partial repairs and rain gutter cleaning!
In urgent cases such as leak repairs, we may be able to provide emergency measures without setting up scaffolding, as long as safety can be ensured, so please consult us!
“I want to know recommended solar panels”, “I want to keep costs as low as possible”, “I just want an estimate for now”, we will provide the best solutions for your specific requests.
We will never propose unnecessary work that prioritizes profit!
We always stand in the customer’s position and will propose the optimal construction plan!
We are confident that we will not 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 Chuo City, Tokyo and Points of Solar Work
The area of Chuo City is 10.115 square kilometers, bordered by Koto and Sumida wards to the east by the Sumida River, and facing Tokyo Bay to the south. Most of the land was reclaimed after the Edo period and is considered a low-lying area with very little elevation. We have summarized the characteristics of the terrain in Chuo City, Tokyo, and points to consider when installing solar panels and storage batteries below. (Tap to open)
View the characteristics of Chuo City, Tokyo, and points for solar construction
■ Low-lying reclaimed land. Check scaffolding, delivery, and shadows for each site
According to the official page of the ward, the east-west length is about 3 kilometers at its longest, and the north-south length is about 5.5 kilometers. Even within this compact area, the size of the site, the distance to adjacent buildings, and the width of the front road vary from house to house, affecting the space for scaffolding, delivery routes for equipment, and the shadows cast by neighboring buildings. Additionally, there are condominium complexes within the ward, and the ward’s subsidies also apply to management associations. Kakeru Koumuten Co., Ltd. plans scaffolding tailored to the site with its own scaffolding team, creates layout diagrams from blueprints and site surveys, and you can confirm this with a power generation simulation.
■ Check the flood and storm surge hazard maps. Pay attention to the installation location of equipment
The hazard maps for Chuo City include versions for the Sumida River, Kanda River, and Nihonbashi River (with a maximum expected total rainfall of 690 millimeters and a maximum hourly rainfall of 153 millimeters) and for the Arakawa River (with an average total rainfall of 632 millimeters over three days), and it is advised to refer to the storm surge inundation area map published by Tokyo. The impact of power conditioners and storage batteries, separate from the panels on the roof, may vary depending on where they are installed indoors or outdoors during flooding. Please check the inundation assumptions for your residence on the ward’s hazard map and consult about the installation location and height in conjunction with the installation conditions of the manufacturer you are using.
■ Roof types and ages vary from house to house. Check the roof and waterproofing before installation
Even within the same ward, roof types, ages, and site shapes vary from house to house. Kakeru Koumuten Co., Ltd. will check the type and condition of the roof and the site situation before installation and propose methods for securing the installation, waterproofing details, and scaffolding plans.
■ The annual sunshine hours at the Tokyo Observatory are about 1,927 hours
According to the Japan Meteorological Agency’s average values (1991–2020), the annual sunshine hours at the Tokyo Observatory are about 1,927 hours, with January (about 193 hours) having the most and June during the rainy season (about 124 hours) having the least. (This is a reference value, not an observation value within Chuo City.)
The power generation amount in Chuo City can also be affected by shadows from surrounding buildings, so it is important to conduct an annual power generation simulation and choose the capacity of the storage battery to match the times of high electricity usage.
Our company handles many exterior construction and solar projects in Chuo City, Tokyo.
We are happy to assist with partial roof repairs such as roof overlay work, roof replacement, and leak repairs, as well as other repairs! Please feel free to consult us for any sudden troubles!
Service Area in Chuo City, Tokyo
Kakeru Koumuten Co., Ltd. accepts requests for work in Kanagawa Prefecture and all areas of Tokyo.
List of Areas in Chuo Ward, Tokyo
Akashicho, Chuo Ward / Irifune, Chuo Ward / Kachidoki, Chuo Ward / Kyobashi, Chuo Ward / Ginza, Chuo Ward / Shinkawa, Chuo Ward / Shintomi, Chuo Ward / Tsukishima, Chuo Ward / Tsukiji, Chuo Ward / Tsukuda, Chuo Ward / Toyosu, Chuo Ward / Nihonbashi, Chuo Ward / Nihonbashi Odengama-cho, Chuo Ward / Nihonbashi Kakigaracho, Chuo Ward / Nihonbashi Kabuto-cho, Chuo Ward / Nihonbashi Kayabacho, Chuo Ward / Nihonbashi Koamicho, Chuo Ward / Nihonbashi Kodenma-cho, Chuo Ward / Nihonbashi Kobune-cho, Chuo Ward / Nihonbashi Tomizawa-cho, Chuo Ward / Nihonbashi Nakasu, Chuo Ward / Nihonbashi Ningyo-cho, Chuo Ward / Nihonbashi Hakozaki-cho, Chuo Ward / Nihonbashi Hamacho, Chuo Ward / Nihonbashi Bakuro-cho, Chuo Ward / Nihonbashi Hisamatsu-cho, Chuo Ward / Nihonbashi Horidome-cho, Chuo Ward / Nihonbashi Hon Ishicho, Chuo Ward / Nihonbashi Honmachi, Chuo Ward / Nihonbashi Muromachi, Chuo Ward / Nihonbashi Yokoyama-cho, Chuo Ward / Hachobori, Chuo Ward / Hamarikyu Gardens, Chuo Ward / Harumi, Chuo Ward / Higashi Nihonbashi, Chuo Ward / Minato, Chuo Ward / Yaesu, Chuo Ward
・For exterior wall painting in Chuo City, Tokyo, trust Kakeru Koumuten Co., Ltd.!
・For roof renovations in Chuo City, Tokyo, trust Kakeru Koumuten Co., Ltd.!
・For exterior renovations in Chuo City, Tokyo, trust Kakeru Koumuten Co., Ltd.!
・Kakeru Koumuten Co., Ltd.’s construction achievements
・Kakeru Koumuten Co., Ltd.’s aftercare services
・Kakeru Koumuten Co., Ltd.’s construction menu and price list
・Kakeru Koumuten Co., Ltd.’s staff blog and announcements
・Explaining the importance of comparative estimates and points to consider!
・Top 12 solar power manufacturers! Features and selection tips included!
・What are the costs of solar power generation? Comprehensive tips to reduce costs!
・What are the best locations for solar power installation? Points for selecting installation sites included!
・Find out about solar power generation estimates here!
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contact Kakeru Koumuten Co., Ltd.
Kakeru Koumuten is a young company whose team is, on average, in their late twenties, but our skills are second to none.
Our greatest strength is that we handle scaffolding, roofing and painting entirely in-house. In an industry where these tasks are usually divided among contractors, our complete service simplifies project management and helps keep costs down. Above all, if a problem arises, we respond promptly.
We proudly describe ourselves as the youngest and most helpful renovation company in Kanagawa!
