Leave the installation of solar panels in Chiyoda, Tokyo to Kakeru Koumuten Co., Ltd.!
For solar panel and battery installation in
Chiyoda Ward, Tokyo,
trust Kakeru Koumuten!
Kakeru Koumuten is a specialized exterior renovation company headquartered in Aoba Ward, Yokohama.
As a company strong in roofing work, we are entrusted withsolar panel and battery installation considering roofs and waterproofing!
“How to Choose a Solar Panel Contractor in Chiyoda Ward”
“Costs for Solar Panel and Battery Installation”
“Subsidies Available for Solar System Installation in Chiyoda Ward”
We will also explain the above three points!
Installing solar panels carries risks such as“the occurrence of leaks” and other troubles.
To ensure a satisfactory solar panel installation, we recommend obtainingthree estimates!
Table of Contents (tap to open/close)
- Reasons Why Kakeru Koumuten is Chosen for Solar Panel Installation in Chiyoda, Tokyo
- Roof Inspection Before Installing Solar Panels
- Possible Subsidies and Grants Available in Chiyoda
- 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 Installation Company in Chiyoda, 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 Chiyoda
- If You’re Looking for a Solar Panel Installation Company in Chiyoda, Contact Kakeru Koumuten
- Characteristics of Chiyoda, Tokyo and Key Points for Solar Installation
- Service Area in Chiyoda, Tokyo
Reasons Why Kakeru Koumuten is Chosen for Solar Panel Installation in Chiyoda, Tokyo
The reasons our company is entrusted with solar panel installation by customers in Chiyoda, Tokyo include
one reason being that “Kakeru Koumuten serves Kanagawa and Tokyo as its service areas”,
and we have “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 Aside from Solar Panel Installation!
Troubles such as leaks that occur during solar panel installation may be caused by insufficient checks on the roof and waterproofing at the installation site.
Even if you are knowledgeable about solar panels, there are cases where the roof and waterproofing at the installation site are outside your expertise, so caution is necessary.
It is reassuring to have knowledge about the roof to avoid maintenance and troubles after installation!
Kakeru Koumuten Co., Ltd. is strong in roofing work and can also detach and attach solar panels in-house, allowing for quick responses to maintenance and urgent troubles after solar panel installation!
2.Facilities Specialized in Exterior Renovation
Kakeru Koumuten Co., Ltd. has organized the following warehouses and material storage areas to provide low-cost, high-quality solar and exterior renovation work.
We have established five bases centered in Yokohama City, Kanagawa Prefecture for material storage and showrooms.
In-house Ownership of Scaffolding Materials
To ensure safety during work on the roof, we own the necessary scaffolding materials for temporary scaffolding based on construction conditions and can assemble scaffolding ourselves.
By performing scaffolding work with our own scaffolding team instead of outsourcing, we can also reduce the cost of scaffolding work.
We have scaffolding materials for approximately 50 single-family homes!
Even in the urban area of Chiyoda Ward, our scaffolding team will plan the scaffolding according to the site conditions.
Storage of materials in our large warehouse
We store roofing materials and paints, and we can also store removed solar panels.
By ordering a large quantity of materials at once, we canpurchase materials at a lower cost!
Additionally, we always have a stock of roofing materials, so we canrespond quickly in emergencies!
Sorting and transporting waste materials in-house
The installation of solar panels often involves roofing work, generating various waste materials such as paint, wood, and metal.
By sorting and recycling waste materials, we can significantly cut waste disposal costs.
Exterior renovation dedicated showroom
In the showroom, not only can you have meetings, but you can also
check the actual foundation brackets for solar panels and see how they are installed on the roofing materials!
Simulations for potential earnings and installation costs when introducing solar panels are also available!
Since roofing and exterior wall work often accompany each other, we also provide samples of roofing materials and models that explain the structure in detail!
3.All Work Performed by Our Own Team
One of Kakeru Koumuten’s major strengths is all work performed by our own team.
By maintaining a consistent system from inquiry to project completion, Kakeru Koumuten can provide high-quality roof remodeling at reduced costs.
Additionally, one representative will handle everything from the estimate to project completion.
Since the same person will manage sales and construction, smooth communication is possible.
We can perform consistent in-house work from temporary scaffolding installation to exterior wall painting and roof remodeling!
4. Various Permits and Skilled Workers
We have obtained construction industry permits and permits for industrial waste collection and transportation!
We also have nationally certified sheet metal and painting technicians, and we are confident in our construction skills.
We can handle large-scale roofing projects such as factories!
5. Warranty and Aftercare
In addition to the manufacturer’s warranty, our solar panel installation work comes with our own workmanship warranty (leakage warranty)!
(The workmanship warranty for solar panel installation is 10 years. Depending on the condition of the roof before installation, we may not be able to provide a warranty unless roof renovation is performed. The workmanship warranty is separate from the manufacturer’s product warranty, and the scope and conditions vary based on the warranty details.)
Aftercare maintenance is available annually, and we send out notification DM every year.
If you have any 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 respond using a drone!
During leakage investigations, we can also conduct inspections using a thermal imaging camera.
If the power generation of the solar panels decreases due to dirt, we can also 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 Clear Materials and Simulations
At Kakeru Koumuten Co., Ltd., we provide not only “estimates,” “layout diagrams,” and “power generation simulations” but also a “solar installation guidebook” and a “financial simulation” that takes into account loan interest rates and electricity costs.
The financial simulation can be created for projected cumulative income and expenses over 20 to 30 years.
Even customers who are not familiar with solar installations will find the materials easy to understand, including important points and potential drawbacks!
We encourage you to obtain comparative estimates and review plans from other companies!
Roof Inspection Before Installing Solar Panels
Once solar panels are installed, they will remain on the roof for 20 to 30 years.
Confirming “whether it is okay to install them directly on the current roof” before installation is the key point to prevent leaks and unnecessary expenses!
Kakeru Koumuten Co., Ltd., which specializes in roofing work, has summarized the items to check before installation.
| 1. Type of roofing material and age | The method of securing the panels varies depending on the roofing material, such as slate, tiles, metal roofs, or flat roofs (roof waterproofing). If the remaining lifespan of the roofing material is short, we may suggest a roof renovation first. |
| 2. Condition of the substrate and waterproof sheet | If the sheathing or roofing (waterproof sheet) beneath the roofing material is damaged, it 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 power generation. We will create a layout diagram from the drawings and the site, and you can verify it with the power generation simulation. |
| 4. Shape of the roof and installable area | The number of panels (installation capacity) that can be placed depends on the shape and size of the roof. The number of panels that can be installed varies depending on their 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 of the fixed parts during the estimate. |
| 6. Weight of the roof | The roof will become heavier due to the panels. After investigating the existing roof, substrate, and load-bearing capacity, replacing with lighter roofing materials may be an option if necessary. |
| 7. Location of equipment installation and wiring | We will check the installation locations for the power conditioner and storage battery, as well as the wiring route to the distribution board. The length of the wiring will also affect costs. |
Fixing Methods and Checkpoints by Roofing Material
| Roof Material | Main Fixing Method | Pre-Installation Check Points |
|---|---|---|
| Slate Roof | Varies by method (e.g., fixing brackets to the roof material and substrate with screws) | Waterproofing of fixed parts, cracks or deterioration of slate, condition of the substrate. If deterioration is significant, consider roof overlay (cover method) or replacement first. |
| Tile Roof | Fixed with brackets and methods suitable for the type of tile (even methods that do not drill holes in the tiles will fix to the substrate) | Type and condition of tiles, substrate, load-bearing capacity. Depending on the investigation results, there may be methods to replace with lighter roofing materials before installation. |
| Metal Roof (Horizontal and Vertical) | Fixed with catch-type brackets that grip the 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 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 Chiyoda, Tokyo
Potential Subsidies and Grants in Chiyoda, Tokyo
If you are introducing solar panels or storage batteries in Chiyoda, Tokyo, there is a possibility that you may be eligible for programs from the “National Government,” “Tokyo Metropolitan Government,” and “Chiyoda Ward”.
The following information is based on the official pages of each program as of October 7, 2026. The application status may change depending on the budget and application period, so please check the latest information before contracting or starting work.
Eligibility Conditions and Application Timing for Subsidy Programs
| Program | Main Eligibility Conditions | Subsidy Amount | Application Period & Status |
|---|---|---|---|
| Tokyo Metropolitan “Reiwa 8 Year Household Solar Power Generation Promotion Project” (Cool Net Tokyo) | New installation of certified solar modules in residential properties or their premises within the Tokyo area, with a system capacity of less than 50kW. Pre-application before installation is required. | Existing homes: 150,000 JPY/kW for up to 3.75kW (maximum 450,000 JPY), 120,000 JPY/kW for over 3.75kW New homes: 120,000 JPY/kW for up to 3.6kW (maximum 360,000 JPY), 100,000 JPY/kW for over 3.6kW (Additional costs for mounting frames, waterproofing work, and renovation defect insurance, etc.) |
Pre-application: From May 29, 2026 Grant application and performance report: From June 30, 2026 to March 30, 2029 |
| Tokyo Metropolitan “Reiwa 8 Year Household Storage Battery Promotion Project” (Cool Net Tokyo) | New installation of storage batteries in residential properties within the Tokyo area, with the requirement that they are SII registered devices. This project is intended for simultaneous installation with solar power, but applications can be made for storage batteries alone. Pre-applications after October 1, 2026 will only be eligible for SII registered products for Reiwa 8. | Storage battery package: 100,000 JPY/kWh (maximum 1,200,000 JPY per household) Storage battery unit expansion: 60,000 JPY/kWh (maximum 720,000 JPY per household) (Additional incentives for participating in DR demonstrations, etc.) |
Pre-application: From May 29, 2026 Grant application and performance report: From June 30, 2026 |
| Chiyoda Ward “Energy Conservation Renovation Subsidy Program” Reiwa 8 Year | Owners of existing buildings (single-family homes, condominiums, etc.) within the ward, or those who have obtained the owner’s consent. New equipment must be installed, with solar power modules certified by JETPVm and storage systems being SII designated subsidy eligible devices. Application before construction is required, and work must commence after receiving the grant decision notification. | Solar power generation & storage systems: 20% of eligible expenses (maximum 1,000,000 JPY) | Application deadline: February 15, 2027 (first-come, first-served) Applications for this fiscal year have temporarily closed as the budget has been reached. Combination with other subsidies is possible. |
| National “DR Home Storage Battery Project” (Reiwa 7 Year Supplement) | New installation of home storage systems that can be utilized for DR (demand response) with registered products. | Calculated based on an initial effective capacity of 34,500 JPY per 1kWh (subsidy rate within 3/10; maximum 600,000 JPY per application) | The budget was reached on May 29, 2026, and the public recruitment has ended. (Currently, applications cannot be made.) |
| National “Mirai Eco Housing 2026 Project” (Renovation) | Storage batteries are one of the eligible facilities, but they must be combined with essential works such as insulation renovation of windows (openings) and the building structure; applications cannot be made for the installation of storage batteries alone. Solar panels are not included as eligible facilities. | Storage battery: 96,000 JPY per household | Ends when the budget limit is reached. Please check the official website for the status. |
In Tokyo, the subsidy requires pre-application before installation, while Chiyoda Ward’s grant requires application and notification of grant decision before construction. If construction begins before these steps, it may become ineligible, and applying does not guarantee funding. The budget for Chiyoda Ward for Reiwa 8 has been reached, and applications are temporarily closed, so please check the ward’s official page for updates on reopening and future systems. Chiyoda Ward’s grant can be combined with other subsidies, but a copy of the notification of the combined subsidy must be submitted upon completion of the work. Procedures differ by system, so please confirm before contracting and starting work.
Kakeru Koumuten Co., Ltd. will guide you on eligibility conditions for each system after confirming them.
Tokyo “Reiwa 8 Household Solar Power Introduction Promotion Project”
Tokyo is providing subsidies for those installing solar power systems in residential homes through Cool Net Tokyo. The target is systems using certified solar modules installed newly in residential homes or on their premises, with a capacity of less than 50kW. Pre-application before installation is required.
For existing homes, the subsidy amount is 150,000 yen/kW for up to 3.75kW (maximum 450,000 yen), and 120,000 yen/kW for over 3.75kW. Additionally, there are extra items for mounting frame installation, waterproofing work, and renovation defect insurance. Pre-applications will be accepted from May 29, 2026, and grant applications and performance reports will be accepted from June 30, 2026, to March 30, 2029. For details on eligible equipment and conditions, as well as the budget status, please check the official page.
👉 Cool Net Tokyo | Official page for solar power is here
Tokyo “Reiwa 8 Household Storage Battery Introduction Promotion Project”
Tokyo is also providing subsidies for newly installed storage batteries in residential homes. The subsidy amount is 100,000 yen per 1kWh of storage battery package (maximum 1,200,000 yen per household), and for additional storage battery units, it is 60,000 yen per 1kWh (maximum 720,000 yen per household), with additional amounts for participation in DR demonstrations.
The target is equipment registered with SII (Environmental Collaboration Initiative). If you apply for pre-application after October 1, 2026, only equipment listed in the Reiwa 8 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. Grant applications and performance reports have been accepted since June 30, 2026.
👉 Cool Net Tokyo | Official page for storage batteries is here
Chiyoda Ward “Energy Conservation Renovation Subsidy System”
In Chiyoda Ward, a “Energy Conservation Renovation Subsidy Program” is being implemented for those who are renovating existing buildings with energy-saving equipment. For residential properties (single-family homes, condominiums, etc.), the subsidy for solar power generation systems and storage systems is 20% of eligible expenses (up to 1,000,000 yen). The installation of unused equipment is a condition, and for solar power generation, modules certified by JET (Japan Electrical Safety & Environment Technology Laboratories) with JETPVm certification (or those recognized by the ward as having equivalent performance) are eligible, while for storage systems, those designated as eligible equipment by SII (Sustainable Open Innovation Initiative) (or those recognized by the ward as having equivalent performance) are eligible.
Applications must be submitted before construction, and construction must begin after receiving the notification of grant decision. Applications are accepted on a first-come, first-served basis, and the application deadline is February 15, 2027; however, the budget for the fiscal year 2026 has been reached, so applications are temporarily closed. You can combine this subsidy with other grants, so a copy of the notification of the combined grants must be submitted upon completion of the work. Please check the ward’s official page for information on the resumption of applications and future programs.
👉 Click here for Chiyoda Ward’s official page (Energy Conservation Renovation Subsidy Program)
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 in the fiscal year 2025 supplementary budget, the subsidy amount was determined based on a standard amount of 34,500 yen per initial effective capacity of 1 kWh, with a subsidy rate of up to 30% and a maximum of 600,000 yen per application. There are also conditions such as that contracts or orders made before the grant decision are not eligible.
However, the application amount for the fiscal year 2025 supplementary budget reached the budget on May 29, 2026, and the public recruitment has ended (the public recruitment for the previous fiscal year 2024 supplementary budget also ended on July 2, 2025). Currently, applications cannot be made, 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.
👉 Click here for the official site of the DR Home Storage Battery Project
Solar Panel Installation & Storage Battery Installation Price List
⇧Service Menu | For Costs Related to Solar Panel Installation and Battery Installation, Click Here
⇧Service Menu | For Costs Related to Solar Panel Removal and 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 greatly 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 “Output of One Panel (W) × Number of Panels”, with the unit being kW (kilowatt). Batteries are compared based on the amount of electricity they can store, expressed in kWh (kilowatt-hour).
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 installation costs 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 estimated amounts and may vary based on factors such as wiring length, scaffolding range, existing roofing materials, and panel layout.)
▶ Installation Menu | Costs for Solar Panel Installation and Battery Installation
Items to Confirm in the Estimate (Cost Confirmation)
When comparing estimates, it is common to compare different capacities and equipment. Please check if the following items are clearly stated in each company’s estimate!
| 1. Solar Panels | Manufacturer, model number, output per panel (W), number of panels, total installation capacity (kW) should be listed. |
| 2. Power Conditioner | Manufacturer, model number, capacity, number of units, installation location (indoor/outdoor). Also check if it is a type that controls the battery together. |
| 3. Battery | Manufacturer, model number, capacity (kWh), range of use during power outages (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, and whether there is a monitor to check power generation. |
| 6. Roof Reinforcement and Waterproofing | Details of waterproofing treatment at fixed points, and whether necessary roof repairs and substrate reinforcements are included. |
| 7. Applications | How much support is included for applications to the power company, feed-in tariff (FIT) certification applications, and subsidy applications. |
| 8. Scaffolding | Range and quantity of scaffolding. If it is simultaneous with roofing work or exterior painting, check that the same range and quantity are not double counted. |
| 9. Removal and Disposal | Whether the removal of existing solar water heaters or old panels and disposal costs for waste materials are included. |
| 10. Tax Classification and Warranty | Whether prices are 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, both the price and power generation will change. Kakeru Koumuten Co., Ltd. welcome comparisons of estimates, so if you bring estimates from other companies, we will explain the differences for each item!
Self-Estimate and Profit Simulation for Solar Power Generation
With the simulator above,
you can get an estimated quote and income simulation for up to 30 years!
If you know the total installation capacity of solar panels on the roof and the capacity of the storage battery, you can get an estimated quote and income simulation!
*The simulation results are estimates. Actual income may vary based on assumptions such as electricity rates, self-consumption ratios, selling prices, and costs for equipment inspection 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)!
Case Studies of Solar Panel Installations
| Construction Details |
| Solar Panel Installation Battery Installation |
| Existing Roofing Material |
| Horizontal Metal Roof (Super Galtect) |
| Installation Capacity |
| Solar Panel: 4.3kW Battery: 5kWh |
| Base Mounting Hardware Used |
| Niigata Manufactured / Aluminum Catch-Type Hardware |
| Fixing Method & Waterproofing Arrangement |
| Fixed by gripping the horizontal metal roof with catch-type hardware (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 when solar panels are 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 Chiyoda, Tokyo
There are many solar panel installation contractors that serve Chiyoda Ward, Tokyo, and you may be unsure which contractor to choose.
Therefore, when requesting solar panel installation and battery storage installation work, make sure to check the following 4 points:
● Have extensive knowledge not only about solar panels but also about roofs
● Confirm the presence of warranties and aftercare maintenance
● 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
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, requiring reinstallation of the solar panels within a few years
・Misjudging the type of waterproofing led to incorrect treatment and subsequent leaks
and more
When installing solar panels, understanding the condition and type of the existing roof allows you to avoid unnecessary expenses and unexpected troubles.
▶ Go to “Roof Verification Before Installing Solar Panels” in this article
Confirm the presence of warranties and aftercare maintenance
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 scope, exclusions, and cost conditions.
While the solar panels and battery storage units come with manufacturer warranties, also check for the presence of a workmanship warranty in case leaks occur after installation!
For contractors that offer workmanship warranties, if leaks occur after installation, they may cover the repairs under 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.
Changes or damage on the roof may occur in areas that are not visible, so there is a possibility that customers may not notice them.
By conducting inspections during after-sales maintenance, even in areas that are not visible, you can more easily prevent major repairs or breakdowns by discovering issues early!
Kakeru Koumuten Co., Ltd. provides a rain leak warranty as part of the workmanship warranty for solar panel installations. (The warranty for solar panel installations is 10 years, and depending on the condition of the roof before installation, a roof renovation may be required to provide the warranty.)
We also conduct after-sales maintenance and send out DM every year!
After checking the DM, if you wish, we will visit for after-sales maintenance!
Obtain estimates from multiple contractors (3 companies as a guideline)
When requesting the installation of solar panels, be sure to obtain estimates from multiple contractors.
Even for the same manufacturer and the same construction content, costs may vary, and warranties and after-sales services may differ.
Additionally, obtaining multiple estimates makes it easier to negotiate prices.
To request services from your preferred contractor at a lower price, we recommend obtaining estimates from multiple contractors.
When comparing estimates, please check the following:
“Check the items in the estimate”
“Type of solar panels”
“Warranties and after-sales services”
Make sure to compare these details carefully! If the quality of the auxiliary materials is low or if steps are skipped, costs can be reduced, so avoid making decisions based solely on price!
▶ Go to “Breakdown of Installation Capacity and Equipment/Construction Costs” in this article
Check if they provide support for subsidy applications
There may be subsidies available for the installation of solar panels and storage batteries, but if the order of procedures is incorrect or if there are deficiencies in the documents, the subsidy may not be granted.
There are systems that require personal applications and cannot be handled by the contractor, as well as systems that require prior application before installation, so it is reassuring to have a contractor that supports the preparation of necessary documents and the flow of procedures.
Complete the procedures specified for each system (for Tokyo’s subsidies, a prior application before installation is required; for Chiyoda Ward’s grants, application and notification of grant decision before construction) before proceeding with the work!
In the case of subsidies in Tokyo, the process involves submitting a grant application and performance report after the completion of the work, which will then be reviewed before the grant is awarded! (The procedure varies depending on the system.)
▶ Go to “Subsidies and Grants that May Be Applicable in Chiyoda Ward” within this article
Benefits of Introducing Solar Power Equipment
The benefits of installing solar panels are as follows!
Benefit 1: Economic Benefits
The biggest advantage of installing solar panels is the economic benefit!
While the selling price of electricity has decreased compared to ten years ago, you can benefit by reducing the amount of electricity purchased from power companies by consuming the generated power yourself!
As electricity prices rise, the ability to cover your consumption with solar power becomes increasingly attractive!
If you plan to use the generated power 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 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 generally more advantageous to use it in your home (self-consumption), making the combination with a storage battery a viable option.
👉 Ministry of the Environment | For purchase prices, periods, etc., click here
Benefit 2: You Can Utilize Subsidies!
The conditions and amounts of subsidies vary by prefecture and municipality, but if you meet the requirements, you may be able to utilize subsidies!
The reduction of the actual burden amount through subsidies is a significant advantage!
In the case of Chiyoda Ward, in addition to national and Tokyo metropolitan programs, there may be eligibility for Chiyoda Ward’s energy-saving renovation subsidy program (solar power systems and storage systems) (the ward’s subsidy requires application before construction, and the budget for the 2026 fiscal year has already reached its limit, temporarily halting acceptance).
Benefit 3: Environmentally Friendly!
Solar power generation has low carbon dioxide emissions and reduces dependence on fossil fuels, contributing to the mitigation of global warming.
Solar panels themselves do not produce noise or exhaust gases during the generation process, making them an environmentally friendly method of power generation. (However, devices such as power conditioners may have operational noise.)
Merit 4 Expect Heat Shielding Effect!!
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, providing a heat shielding effect!
(Note that this does not improve the insulation performance of the building itself.)
Merit 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 reattaching 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 would be reassuring to ask for a simulation that considers maintenance costs before introducing solar panels!
Point 2 The risk of leaks increases depending on the roofing material
The methods for securing slate roofs and tile roofs vary depending on the construction method, but when using screws and other fasteners to secure the roofing materials and substrate, waterproofing at the fastening points becomes crucial.
In methods that involve making holes in the roof, the risk of leaks inevitably arises.
Of course, we will ensure thorough waterproofing, but if you are concerned about making holes, one option is to replace the roofing material with a metal roof and secure the solar panels using the catch method. (The catch method has compatibility conditions between the roofing material and the fasteners, and it cannot be used with all metal roofs.)
Catch-type base fastener for horizontal metal roofs
Note 3: The roof will become heavier
Since solar panels will be installed, the roof will become heavier. After investigating the existing roof, substrate, and load-bearing capacity, replacing 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 know how much electricity can be generated in a limited area, and the more electricity generated, the better!
Solar panels vary in size and output depending on the manufacturer.
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 panel does not fit well with the roof, “20 panels of 350W can be installed, while only 15 panels of 400W can be installed,” meaning that the number of panels that can be installed may differ even on the same roof due to the size difference.
400W×15 panels = 6kW (total output of the roof)
350W×20 panels = 7kW (total output of the roof)
As shown above, even if the output of a single panel is lower, the total output of the roof may be higher!
It is important to consider the total output of the roof rather than the output of a single panel!
*The above is a calculation of total output (kW). The actual electricity generation (kWh) will vary depending on conditions such as the roof’s 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 and 20 years.
The degree of output reduction after long-term use varies by product. The manufacturer’s output guarantee value is a benchmark for the warranty and does not indicate the actual degradation rate or power generation amount.
Choosing solar panels while considering the degradation rate, not just the initial output, will lead to a decision you won’t regret!
How to Choose 3: Compare by Warranty Period
There are several types of warranties for solar panels, including “output warranty,” “natural disaster warranty,” and “system warranty,” and the warranty periods vary by manufacturer.
Some manufacturers offer a 30-year warranty for output, while others provide a 10-year warranty, so it varies widely!
A longer warranty is always better, so be sure to check the warranty period and conditions of the manufacturers you are considering!
Frequently Asked Questions about Solar and Battery Installation in Chiyoda Ward
We have compiled frequently asked questions from customers considering the installation of solar panels and batteries in Chiyoda Ward. (Tap to open the answers)
How much does it cost to install solar panels and batteries in Chiyoda Ward, Tokyo?
The cost varies depending on the installation capacity, equipment, and roof condition. In the above construction example (solar panel 4.3kW + battery, completed in April 2025), it was 2.2 million yen to 2.3 million yen.
For cost estimates by capacity, please refer to the solar panel and battery installation pricing page. We will create a layout diagram from the drawings and on-site survey and provide a free estimate!
Are there any subsidies available for solar and battery installation in Chiyoda Ward?
As of October 7, 2026, Tokyo’s subsidies for solar power generation and batteries (Cool Net Tokyo) are accepting pre-applications. For batteries, only SII registered devices (registered products for Reiwa 8) will be eligible from pre-applications made after October 1, 2026. The Chiyoda Ward energy-saving renovation subsidy program (20% of eligible expenses for both solar and battery systems, with a cap of 1 million yen) has reached its budget for Reiwa 8 and is temporarily closed for applications. The national DR home battery project has also ended its public recruitment.
Since the application status may change, please check the subsidy and grant section and consult with us before signing a contract.
Can I apply for subsidies after the construction is completed?
For many programs, procedures are required before construction. Tokyo’s subsidies require pre-application before installation, and if you install first, you will be ineligible. The Chiyoda Ward subsidy also requires application and notification of grant decision before construction, and starting work beforehand will make you ineligible. Procedures vary by program.
Since the order of procedures differs by program, please confirm before signing a contract or 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 beforehand. The fixing method varies depending on the construction method, and when using brackets to secure the roofing material or substrate, waterproofing treatment of the fixed parts is essential.
Kakeru Koumuten Co., Ltd. is a specialized exterior renovation company strong in roofing work, so we will check the condition of the roof before installation and suggest methods such as roof overlay (cover method) or 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 about the installation process after checking the condition of the roof during the on-site survey!
Should I install a storage battery together with the solar panels?
If you want to use the generated electricity at night or prepare for power outages, simultaneous installation is recommended. The selling price for electricity will be 8.3 yen/kWh after the fifth year, making it more advantageous to use it in your home rather than selling it.
Additionally, the Tokyo Metropolitan Government’s subsidy for storage batteries is a program intended 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.
Even in the urban area of Chiyoda Ward, the way shadows are cast by surrounding buildings varies from house to house. You can check the expected power generation through the power generation simulation.
How long will the construction take?
For the above construction example (solar panels 4.3 kW + storage battery), it took about 3 days. The duration may vary depending on whether roofing work is done simultaneously and the shape and installation capacity of the roof.
Please note that there will be an additional period for applications for subsidies and power companies, so please consult us as soon as possible.
What is the current selling price (FIT)?
For residential use (less than 10 kW), the selling price from certifications after October 2025 will be 24 yen/kWh for the first 4 years, and 8.3 yen/kWh from the 5th to the 10th year, and the same price will apply for the 2026 fiscal year.
The idea is to recover initial costs more quickly in the first 4 years and then focus on self-consumption. Kakeru Koumuten Co., Ltd. provides a financial simulation that takes into account loan interest rates and electricity rates.
Can you handle maintenance and inspections after installation?
Yes, we can. Kakeru Koumuten Co., Ltd. sends out annual after-maintenance DM notices and visits customers who wish for inspections. We can also clean solar panels with a special brush if the power generation decreases due to dirt.
The roof is a place 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, it is possible. Kakeru Koumuten Co., Ltd. can detach and reattach solar panels in-house, allowing us to remove the panels, perform roof overlay (cover method) or re-roofing, and then reinstall them consistently. The removed panels can be stored in our own warehouse.
For costs, please refer to the solar panel detachment and water heater removal pricing page.
If you are looking for a solar panel installation company in Chiyoda Ward, please consult Kakeru Koumuten
Our company handles a wide range of exterior renovations, including solar panel installation, roof work, and exterior wall work in Chiyoda Ward, Tokyo.
We have received many requests from customers, including renovation companies and real estate agencies!
Kakeru Koumuten promises “high-quality renovations at low cost”, and we have received positive feedback from many customers.
We continue to update our construction performance every year, and we will strive to improve quality to satisfy even more customers in the future.
Our company can perform not only roof overlay work and re-roofing but also partial roof repairs, exterior painting, and exterior wall cover methods, all with our own team.
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 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 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 we are found to be inferior to other companies, you are free to decline!
Characteristics of Chiyoda Ward, Tokyo, and Points for Solar Construction
Chiyoda Ward, located in the center of Tokyo, is an area that spreads around the Imperial Palace, featuring business districts such as Otemachi and Marunouchi, as well as neighborhoods like Akihabara, Kanda, and Jimbocho. The official page of Chiyoda Ward provides hazard maps for floods (Kanda River version, Arakawa version), storm surges, and landslide disasters.
We have summarized the points to consider when installing solar panels and storage batteries in Chiyoda Ward’s residential environment below. (Tap to open)
View the characteristics of Chiyoda Ward and points for solar installation
■ Confirm the installation location of storage batteries and power conditioners in line with the hazard map
Chiyoda Ward’s hazard map allows you to check the assumptions for floods targeting the Kanda River, Nihonbashi River, and Sumida River, as well as floods due to the breach of the Arakawa levee, storm surges, and landslide disasters. When deciding on the installation location for storage batteries and power conditioners, it is reassuring to check the flood assumptions for your residence on the hazard map and consider the height and position of the installation.
■ Tokyo’s annual sunshine hours are approximately 1,927 hours
The Japan Meteorological Agency’s average values (1991–2020) indicate that Tokyo receives about 1,927 hours of sunshine annually.
Since the amount of electricity generated varies by season, it is important to conduct annual generation simulations and select the capacity of storage batteries to match the times when electricity is heavily used.
■ Check for shadows from surrounding buildings in areas with nearby buildings or mid-rise structures
In business districts or areas with closely built mid-rise structures, the shadows cast by surrounding buildings differ for each house depending on the orientation and height of the roof or rooftop. Since solar panels generate less electricity when shaded, Kakeru Koumuten creates layout diagrams based on blueprints and the actual site conditions, allowing you to confirm through generation simulations.
■ Not only single-family homes but also condominium units are eligible for the district’s subsidies
Chiyoda Ward’s energy-saving renovation subsidy program includes not only single-family homes but also condominium units. Installing on the rooftops of condominiums may require the agreement of the management association and confirmation of ownership relations, so please consult us in advance.
■ In places with narrow front roads, plan scaffolding and equipment delivery carefully
In locations with narrow front roads or where surrounding buildings are close together, careful planning for scaffolding and equipment delivery may be necessary. Kakeru Koumuten will respond to site conditions with our own scaffolding team and scaffolding materials.
■ Check the roof condition according to the building’s age
For buildings that have been around for several years, it is important to check the condition of the roofing materials and substrate before installing solar panels. Depending on the roof’s condition, installing them simultaneously with roof renovations can help reduce future costs for removing and reinstalling solar panels.
■ Subsidies require procedures before construction from both Tokyo and Chiyoda Ward
Tokyo’s subsidies require pre-application to Cool Net Tokyo before installation. Chiyoda Ward’s energy-saving renovation subsidy program also requires application and notification of approval before construction. It is important to check the procedures and timelines for each program in advance, in line with the timing of the construction.
Our company serves Kanagawa Prefecture and Tokyo, and we handle many exterior construction and solar power projects in Chiyoda Ward, Tokyo.
We are happy to assist with partial roof repairs such as roof overlay work, roof replacement, and leak repairs, as well as other repairs! Please feel free to consult us for any urgent issues!
Service Area in Chiyoda Ward, Tokyo
Kakeru Koumuten Co., Ltd. accepts requests across all of Kanagawa Prefecture and Tokyo.
List of Areas in Chiyoda Ward, Tokyo
Iidabashi, Chiyoda Ward / Ichibancho, Chiyoda Ward / Iwamotocho, Chiyoda Ward / Uchikanda, Chiyoda Ward / Uchisaiwaicho, Chiyoda Ward / Otemachi, Chiyoda Ward / Kajicho, Chiyoda Ward / Kasumigaseki, Chiyoda Ward / Kanda Aioicho, Chiyoda Ward / Kanda Awajicho, Chiyoda Ward / Kanda Izumicho, Chiyoda Ward / Kanda Iwamotocho, Chiyoda Ward / Kanda Ogawacho, Chiyoda Ward / Kanda Kajicho, Chiyoda Ward / Kanda Kitano Moromachi, Chiyoda Ward / Kanda Konyacho, Chiyoda Ward / Kanda Sakumakawagashi, Chiyoda Ward / Kanda Sakumacho, Chiyoda Ward / Kanda Sarugakucho, Chiyoda Ward / Kanda Jinbocho, Chiyoda Ward / Kanda Sudacho, Chiyoda Ward / Kanda Surugadai, Chiyoda Ward / Kanda Tamachi, Chiyoda Ward / Kanda Tsukasa, Chiyoda Ward / Kanda Toyamacho, Chiyoda Ward / Kanda Nishifukudacho, Chiyoda Ward / Kanda Nerenbai, Chiyoda Ward / Kanda Hanaokacho, Chiyoda Ward / Kanda Higashikonyacho, Chiyoda Ward / Kanda Higashimatsushitacho, Chiyoda Ward / Kanda Hirakawacho, Chiyoda Ward / Kanda Matsunagacho, Chiyoda Ward / Kanda Mikuracho, Chiyoda Ward / Kanda Misakicho, Chiyoda Ward / Kanda Midoricho, Chiyoda Ward / Kioicho, Chiyoda Ward / Kitano Marukoen, Chiyoda Ward / Kudansouth, Chiyoda Ward / Kudannorth, Chiyoda Ward / Imperial Palace Outer Garden, Chiyoda Ward / Kojimachi, Chiyoda Ward / Gobancho, Chiyoda Ward / Sanbancho, Chiyoda Ward / Sotokanda, Chiyoda Ward / Chiyoda, Chiyoda Ward / Nagatacho, Chiyoda Ward / Nishikanda, Chiyoda Ward / Nibancho, Chiyoda Ward / Hayabusa-cho, Chiyoda Ward / Higashikanda, Chiyoda Ward / Hitotsubashi, Chiyoda Ward / Hibiya Park, Chiyoda Ward / Hirakawacho, Chiyoda Ward / Fujimi, Chiyoda Ward / Marunouchi, Chiyoda Ward / Yurakucho, Chiyoda Ward / Yobanchō, Chiyoda Ward / Rokubancho, Chiyoda Ward
・Trust Kakeru Koumuten for exterior wall painting in Chiyoda, Tokyo!
・Trust Kakeru Koumuten for roof renovations in Chiyoda, Tokyo!
・Trust Kakeru Koumuten for exterior renovations in Chiyoda, Tokyo!
・Kakeru Koumuten Co., Ltd.施工実績
・Kakeru Koumuten Co., Ltd. after maintenance
・Kakeru Koumuten Co., Ltd.施工メニュー・料金表
・Kakeru Koumuten Co., Ltd. staff blog and announcements
・Explaining the importance of getting multiple estimates and points to compare!
・Top 12 solar power generation manufacturers! Features and selection tips included!
・What are the installation costs for solar power generation? Tips for reducing costs thoroughly explained!
・What are the best locations for installing solar power generation? Points for selecting installation locations included!
・Here for solar power generation estimates!
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contact Kakeru Koumuten Co., Ltd.
Kakeru Koumuten is a young company whose team is, on average, in their late twenties, but our skills are second to none.
Our greatest strength is that we handle scaffolding, roofing and painting entirely in-house. In an industry where these tasks are usually divided among contractors, our complete service simplifies project management and helps keep costs down. Above all, if a problem arises, we respond promptly.
We proudly describe ourselves as the youngest and most helpful renovation company in Kanagawa!
