Leave Your Solar Panel Installation Work in Inagi City, Tokyo to Kakeru Koumuten Co., Ltd.!
For solar panel and battery installation in
Inagi City, Tokyo,
trust Kakeru Koumuten!
Kakeru Koumuten is a specialized exterior renovation company headquartered in Aoba Ward, Yokohama City.
As a company strong in roofing work, we are entrusted withsolar panel and battery installation considering roofs and waterproofing!
“How to Choose a Solar Panel Contractor in Inagi City”
“Costs for Solar Panel and Battery Installation”
“Subsidies Available for Solar System Installation in Inagi City”
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 Inagi City, Tokyo
- Roof Inspection Before Installing Solar Panels
- Possible Subsidies and Grants Available in Inagi City
- 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 Inagi 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 Inagi City
- If You Are Looking for a Solar Panel Installation Company in Inagi City, Contact Kakeru Koumuten
- Characteristics of Inagi City, Tokyo and Key Points for Solar Installation
- Service Area in Inagi City, Tokyo
Reasons Why Kakeru Koumuten is Chosen for Solar Panel Installation in Inagi City, Tokyo
The reasons why our company is entrusted with solar panel installation by customers in Inagi City, Tokyo
One reason is that “Kakeru Koumuten covers Kanagawa and Tokyo as its service areas.” However,
“We have unique strengths in solar panel installation that cannot be imitated by other companies,” which has received high praise from many customers.
We would appreciate it if you could compare our estimates with those of other companies.
Because we are confident, we welcome estimates from any number of companies!
1. We Can Also Handle Exterior Renovations Other Than Solar Panel Installation!
Troubles such as leaks caused by solar panel installation may be due to insufficient checks on the roof and waterproofing at the installation site.
Even if you are knowledgeable about solar panels, there are cases where the roof and waterproofing at the installation site are outside your expertise, so caution is necessary.
It is reassuring to have expertise in roofing to avoid maintenance and troubles after installation!
Kakeru Koumuten Co., Ltd. is strong in roofing work and can also detach and attach solar panels in-house, allowing for quick responses to maintenance and urgent troubles after solar panel installation!
2.Facilities Specialized in Exterior Renovation
Kakeru Koumuten Co., Ltd. has organized the following warehouses and material storage areas to provide low-cost, high-quality solar work and exterior renovations.
We have established five bases centered around Yokohama City, Kanagawa Prefecture for material storage and showrooms.
In-house 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 set up scaffolding ourselves.
By performing scaffolding work with our own scaffolding team instead of outsourcing, we can also cut costs for scaffolding work.
We have scaffolding materials for approximately 50 single-family homes!
In Inagi City, our own 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 paints, wood, and metal.
By sorting and recycling waste materials, we can significantly cut waste disposal costs.
Exterior remodeling dedicated showroom
In the showroom, not only can you have meetings, but you can also
check the actual foundation brackets for solar panels and see how they are installed on the roofing materials!
It is also possible to simulate the revenue and installation costs when introducing solar panels!
Since roofing and exterior wall work often accompany each other, we also provide samples of roofing materials and models that explain the structure, allowing for detailed explanations!
3.All Work Performed by Our Own Team
One of Kakeru Koumuten’s major strengths is all work performed by our own team.
By maintaining a consistent system from inquiry to project completion, Kakeru Koumuten can provide high-quality roof remodeling at reduced costs.
Additionally, one representative will handle everything from the estimate to project completion.
Since the person in charge does not change, whether it’s the sales representative or the construction management representative, 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 workers and painting technicians, and we are confident in our construction skills.
We can also handle large-scale roofing work for factories and other facilities!
5. Warranty and Aftercare
In addition to the manufacturer’s warranty, our solar panel installation work comes with our own workmanship warranty (leakage warranty)!
(The workmanship warranty for solar panel installation is 10 years. Depending on the condition of the roof before installation, a roof renovation may be required to provide the warranty. The workmanship warranty is separate from the manufacturer’s product warranty, and the coverage and conditions vary based on the warranty details.)
Aftercare maintenance is available annually, and we send out notification DM each 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 roof troubles and situations.
If you cannot access the roof due to height, we can utilize a drone for inspections!
During leakage investigations, we can also conduct surveys using a thermal imaging camera.
If the power generation of the solar panels decreases due to dirt, we can perform cleaning with a specialized brush.
We will respond according to your preferences.
7. Human Resource Development
To improve skills, we create various roof models and conduct practical training.
Since the construction methods vary depending on the shape and slope of the roof, we regularly provide technical training to ensure that each staff member can handle various cases.
8. Creation of Easy-to-Understand Materials and Simulations
At Kakeru Koumuten, 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 project cumulative income and expenses over 20 to 30 years.
Even customers who are not familiar with solar installations will find our materials easy to understand, including important points and disadvantages!
We encourage you to obtain comparative estimates and review plans from other companies!
Roof Inspection Before Installing Solar Panels
Once solar panels are installed, they will remain on the roof for 20 to 30 years.
It is crucial to confirm before installation whether it is safe to place them directly on the current roof, as this is the key point to prevent leaks and unnecessary expenses!
Kakeru Koumuten, specializing 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 can affect the fastening strength and waterproofing. We will also check for any signs of leaks. |
| 3. Orientation, slope, and shadows of the roof | The orientation and slope of the roof surface, as well as shadows from neighboring houses, trees, and utility poles, can affect power generation. We will create a layout diagram based on the drawings and the site, and you can 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. Method of securing 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 fastening method varies by technique, so please check the waterproofing treatment method for the fastening parts during the estimate. |
| 6. Weight of the roof | The roof will become heavier due to the panels. After investigating the existing roof, substrate, and load-bearing capacity, replacing with lighter roofing material may be an option if necessary. |
| 7. Location of equipment installation and wiring | We will check the installation location of the power conditioner and storage battery, as well as the wiring route to the distribution board. The length of the wiring also affects costs. |
Securing Methods and Checkpoints by Roofing Material
| Roof Material | Main Fixing Method | Pre-Installation Check Points |
|---|---|---|
| Slate Roof | Varies by method (e.g., fixing brackets to the roof material and substrate with screws) | Waterproofing treatment 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 suited to the type of tile (even methods that do not drill holes in the tiles will fix to the substrate) | Type and condition of tiles, substrate, load-bearing capacity. Depending on the investigation results, there may be methods to replace with lighter roof materials before installation. |
| Metal Roof (Horizontal and Vertical) | Fixed with catch-type brackets that grip the roof material (depends on the combination of roof material and brackets) | Whether the roof material and brackets are compatible, installation conditions from the roof material manufacturer. If compatible, methods that do not drill holes may be available. |
| Flat Roof / Rooftop | Fixed by installing a framework | Type and deterioration status of the waterproof layer, waterproofing around the framework. Consider in conjunction with the timing of waterproofing work. |
If you renovate the roof 10 to 20 years after installation, additional costs for removing and reinstalling solar panels will apply. If the roof is deteriorating, renovating to a highly durable roof 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 Inagi City, Tokyo
Subsidies and Grants Available inInagi City, Tokyo
If you are introducing solar panels or storage batteries in Inagi City, Tokyo, you may be eligible for programs from the “National Government,” “Tokyo Metropolitan Government,” and “Inagi City”.
The following information is based on the official pages of each program as of October 7, 2026. The application status may change depending on budget and recruitment periods, so please check the latest information before contracting or starting work.
Eligibility Conditions and Application Timing for Subsidy Programs
| Program | Main Eligibility Conditions | Subsidy Amount | Application Period & Status |
|---|---|---|---|
| Tokyo “Reiwa 8 Year Household Solar Power Generation Promotion Project” (Cool Net Tokyo) | New installation of certified solar modules in residential properties or their premises within Tokyo, 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 “Reiwa 8 Year Household Storage Battery Promotion Project” (Cool Net Tokyo) | New installation of storage batteries in residential properties within Tokyo, 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 only. Pre-applications after October 1, 2026 will only be eligible for SII registered products for Reiwa 8. | Storage battery package: 100,000 JPY/kWh (maximum 1,200,000 JPY per household) Storage battery unit expansion: 60,000 JPY/kWh (maximum 720,000 JPY per household) (Additional incentives for participation in DR demonstrations, etc.) |
Pre-application: From May 29, 2026 Grant application and performance report: From June 30, 2026 |
| Inagi City “Carbon Neutral Housing Equipment Subsidy” Reiwa 8 Year | Homeowners in the city who have been residing there prior to application, with no delinquency on individual resident taxes, etc. Post-application after completion of construction/installation for items installed between March 1, 2026 and February 28, 2027. Buyers of new homes with eligible equipment are also included. | Solar power generation equipment: 20,000 JPY per kW (maximum 80,000 JPY) Storage battery system: Flat rate of 40,000 JPY |
Application acceptance: From July 1, 2026 to March 5, 2027 (first-come, first-served) As of October 2, 2026, the official city page states that 74.8% of the budget has been applied for. The program will end once the budget limit is reached. |
| National “DR Household Storage Battery Project” (Reiwa 7 Year Supplement) | New installation of household storage systems that can be utilized for DR (demand response) with registered products. | Calculated based on a standard amount of 34,500 JPY per initial effective capacity of 1 kWh (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 (applications are currently not accepted). |
| National “Mirai Eco Housing 2026 Project” (Renovation) | Storage batteries are one of the eligible facilities, but they must be combined with essential works such as insulation renovation of windows (openings) and the structure; applications cannot be made for storage battery installation alone. Solar panels are not included as eligible facilities. | Storage battery: 96,000 JPY per household | Ends when the budget limit is reached. Please check the official website for the application status. |
In Tokyo, a pre-application before installation is required for subsidies, and starting construction beforehand may result in ineligibility. In Inagi City, the subsidy is a post-application after the completion of construction and installation, and it is on a first-come, first-served basis, so applications will close once the budget is reached. In both cases, it is necessary to meet the required equipment and conditions, and applying does not guarantee that the subsidy will be granted. For information on combining with national and Tokyo subsidies, please check the official pages of each program. The procedures differ by program, so please confirm before contracting and starting work.
Kakeru Koumuten will guide you on the eligibility conditions for each program after confirming them.
Tokyo “Reiwa 8 Year Household Solar Power Generation Promotion Project”
In Tokyo, subsidies are provided for those installing solar power generation systems in residential homes through Cool Net Tokyo. The eligible systems are those using certified solar modules installed newly in residential homes or on their premises, with a capacity of less than 50kW. A pre-application before installation is required.
For existing homes, the subsidy amount is 150,000 JPY/kW for up to 3.75kW (maximum 450,000 JPY), and 120,000 JPY/kW for systems exceeding 3.75kW. Additionally, there are extra items for mounting frames, waterproofing work, and renovation defect insurance. The pre-application period is from May 29, 2026, and the application for subsidy and performance report is from June 30, 2026, to March 30, 2029. For details on eligible equipment and conditions, as well as the budget status, please check the official page.
👉 Cool Net Tokyo | Official page for solar power generation is here
Tokyo “Reiwa 8 Year Household Storage Battery Promotion Project”
Tokyo is also providing subsidies for newly installed storage batteries in residential homes. The subsidy amount is 100,000 JPY per 1kWh for storage battery packages (maximum 1,200,000 JPY per household), and 60,000 JPY per 1kWh for additional storage battery units (maximum 720,000 JPY per household), with additional amounts for participation in DR demonstrations.
The eligible equipment must be registered with SII (Environmental Collaboration Initiative). If applying for pre-application after October 1, 2026, only equipment listed in the Reiwa 8 year SII registered products will be eligible. This project is intended for simultaneous installation with solar power, but applications can be made for storage batteries alone. The application for subsidy and performance report has been open since June 30, 2026.
👉 Cool Net Tokyo | Official page for storage batteries is here
Inagi City “Carbon Neutral Housing Equipment Subsidy”
Inagi City is providing subsidies for those introducing decarbonization-related equipment into their homes. The subsidy amount for the Reiwa 8 year is 20,000 JPY per 1kW for solar power generation equipment (maximum 80,000 JPY), and a fixed amount of 40,000 JPY for storage battery systems. Eligible applicants are homeowners in the city, and conditions include residing in the home prior to application and having no delinquency in individual resident tax. Buyers of newly constructed homes that have installed eligible equipment are also eligible.
Applications are for post-construction applications after completion, targeting installations made between March 1, 2026, and February 28, 2027. Application acceptance will be from July 1, 2026, to March 5, 2027, and will end once the budget limit is reached on a first-come, first-served basis. Applications will be submitted via the LoGo form (electronic application). As of October 2, 2026, the official city page states that the application rate against the budget amount is 74.8%. Please check the official page for the requirements for eligible equipment and necessary documents.
👉 Here is the official page of Inagi City (Reiwa 8 Carbon Neutral Housing Equipment Subsidy)
National Subsidy “DR Home Battery Project (Support Project for Home Battery Systems for DR Resource Introduction)”
The national government has been implementing the “DR Home Battery Project” to support the installation of home batteries.
This program targets those who are newly introducing registered products’ battery systems that can be utilized for demand response (DR). In the fiscal year 2025 supplementary budget, the subsidy amount was determined based on a standard amount of 34,500 JPY per initial effective capacity of 1 kWh, with a subsidy rate of up to 30% and a maximum of 600,000 JPY per application. There are also conditions such as excluding those contracted or ordered before the grant decision.
However, the fiscal year 2025 supplementary budget applications reached the budget on May 29, 2026, and the public recruitment has ended (the previous fiscal year 2024 supplementary budget also ended public recruitment on July 2, 2025). Applications are currently not possible, so please check the official site for future public recruitment.
Additionally, there are currently no subsidies confirmed for the installation of solar panels on existing homes.
👉 Here is the official site for the DR Home Battery Project
Solar Panel Installation & Battery Installation Price List
⇧Service Menu | For costs regarding solar panel installation and battery installation, click here
⇧Service Menu | Click here for costs related to Solar Panel Removal and Hot Water Heater Dismantling
Breakdown of Installation Capacity, Equipment, and Construction Costs
The costs for solar panels and storage batteries should be confirmed by separating them into “Equipment Costs (Device Costs)” and “Construction Costs”.
Even for the same “Complete Solar Panel Installation,” the amount can vary greatly depending on the installation capacity, equipment grade, and roof condition.
Considerations for Installation Capacity (kW) and Storage Battery Capacity (kWh)
The installation capacity of solar panels is determined by “Output of One Panel (W) × Number of Panels”, with the unit being kW (kilowatts). Storage batteries are compared based on the amount of electricity they can store, represented in kWh (kilowatt-hours).
The amount of kW that can be installed on a roof varies for each house based on the shape, orientation, and size of the roof. At Kakeru Koumuten, we create layout diagrams from blueprints and on-site surveys to present the installation capacity.
On our pricing page, we list solar panels as approximately 800,000 JPY to 1,200,000 JPY for 3-5 kW and 1,200,000 JPY to 1,900,000 JPY for 6-10 kW. (These are just approximate amounts and can vary based on wiring length, scaffolding range, existing roofing materials, and panel layout.)
▶ Service Menu | Click here for costs related to Solar Panel and Storage Battery Installation
Items to Check on the Estimate (Cost Confirmation)
When comparing estimates, it is common to compare different capacities and equipment by only looking at the amounts. Please check if the following items are clearly stated in the estimates from each company!
| 1. Solar Panels | Manufacturer, model number, output per panel (W), number of panels, total installation capacity (kW) should be listed. |
| 2. Power Conditioner | Manufacturer, model number, capacity, number of units, installation location (indoor/outdoor). Also check if it is a type that controls in conjunction with a storage battery. |
| 3. Storage Battery | Manufacturer, model number, capacity (kWh), range of use during power outages (entire house or specific circuits), installation location. |
| 4. Mounting Frame and Hardware | Name of hardware suitable for roofing material 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 at fixed points, whether necessary roof repairs and substrate reinforcements are included. |
| 7. Applications | Extent of support for applications to the power company, certification application for selling electricity (FIT), and subsidy applications. |
| 8. Scaffolding | Scope and quantity of scaffolding. If roofing work and exterior wall painting are done simultaneously, check that the same scope and quantity are not double-counted. |
| 9. Removal and Disposal | Whether the removal of existing solar thermal water heaters and old panels, as well as disposal costs for waste materials, are included. |
| 10. Tax Classification and Warranty | Whether prices are tax-inclusive or tax-exclusive, conditions under which additional costs may arise, details and duration of manufacturer warranty and workmanship warranty. |
If the capacities differ, both the price and power generation will change. Kakeru Koumuten Co., Ltd. warmly welcomes competitive estimates, so if you bring estimates from other companies, we will explain the differences for each item!
Self-Estimate and Profit Simulation for Solar Power Generation
With the simulator above,
you can obtain an estimated quote and a profit simulation for up to 30 years!
If you know the total installation capacity of solar panels on the roof and the capacity of the storage battery, you can get an estimated quote and profit simulation!
*The simulation results are estimates. Actual profits will vary based on assumptions such as electricity rates, self-consumption ratios, selling prices, and costs for equipment inspection and replacement.
Customer Voices
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customer reviews
Asao-ku, Kawasaki City | We received reviews about the ridge cap and rain gutter replacement work!
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customer reviews
Kohoku-ku, Yokohama | We received reviews about the roof overlay (cover method)!
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customer reviews
Kohoku-ku, Yokohama | We Received Reviews About Exterior Painting!
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customer reviews
Hodogaya-ku, Yokohama | We received reviews about our exterior fence construction!
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customer reviews
Tsurumi-ku, Yokohama | We received reviews about roof and exterior wall painting, as well as metalwork and rain gutter replacement work!
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customer reviews
Higashiyamato City, Tokyo | We received reviews about exterior painting and roof overlay (cover method)!
Examples of Solar Panel Installation
| Work Details |
| Solar Panel Installation Battery Installation |
| Existing Roofing Material |
| Horizontal Metal Roof (Super Galtect) |
| Installation Capacity |
| Solar Panel: 4.3kW Battery: 5kWh |
| Base Mounting Hardware Used |
| Niigata Manufactured / Aluminum Catch Type Hardware |
| Fixing Method & Waterproofing Arrangement |
| Fixed using catch type hardware gripping the horizontal metal roof (Catch Method) |
| Price Range |
| 2,200,000 JPY～2,300,000 JPY *Due to the grant being provided, the actual burden amount is approximately 1,000,000 JPY Estimated recovery period for construction costs: about 8 to 9 years (self-consumption) *The grant amount and recovery estimate are based on the system and calculations at the time of construction and may differ under the current system. |
| Construction Period |
| Approximately 3 days |
| Completion Month |
| April 2025 |
| Inquiry Details |
| I am considering the installation of solar panels and storage batteries. I heard that grants are available, and I would like to know how much can be provided. |
Our Proposal
We visited to provide an estimate and created a layout diagram for the solar panels 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 the grant, so we explained it to the customer along with the estimate!
How to Choose a Solar Panel Installation Contractor in Inagi City, Tokyo
There are many solar panel installation contractors available in Inagi City, Tokyo, and you may be unsure which contractor to choose.
Therefore, when requesting solar panel installation and storage battery installation work, let’s check the following 4 points.
● Have extensive knowledge not only about solar power but also about roofs
● Confirm the presence of warranties and after-sales maintenance
● Obtain estimates from multiple contractors (3 companies as a guideline)
● Check if they provide support for subsidy applications
By confirming the above 4 points, you will be able to choose a reliable contractor.
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 confirmation regarding roofs and waterproofing.
While knowledge about solar panels is certainly important, understanding the roof and waterproofing at the installation site of the solar panels is also crucial.
⚠︎Examples of troubles due to insufficient confirmation of roofs and waterproofing
・Solar panels installed on a severely deteriorated roof causing leaks
・Solar panels installed on a roof with a short lifespan, requiring a renovation for removal and reinstallation within a few years
・Incorrect treatment due to misjudging the type of waterproofing, leading to leaks
and more
When installing solar panels, understanding the condition and type of the existing roof allows you to avoid unnecessary expenses and unforeseen troubles.
▶ Go to “Roof Confirmation Before Installing Solar Panels” in this article
Confirm the presence of warranties and after-sales maintenance
When choosing a solar installation contractor, let’s confirm the presence of warranties. It’s important to check not only the duration of the warranty but also the coverage, exclusions, and cost conditions.
While the solar panels and storage batteries come with a manufacturer’s warranty, also check for the presence of a workmanship warranty in case leaks occur after installation!
For contractors that offer a workmanship warranty, if leaks occur after installation, they may be able to address the issue under the warranty, as long as it falls 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, we can easily detect abnormalities early and prevent major repairs or breakdowns!
Kakeru Koumuten Co., Ltd. provides a leak warranty as part of the workmanship warranty for solar panel installations. (The warranty for solar panel installations is 10 years, and depending on the condition of the roof before installation, we may not be able to provide a warranty unless a roof renovation is performed.)
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 solar panel installation, be sure to obtain estimates from multiple contractors.
Even for the same manufacturer and the same construction content, costs may vary, and warranties and after-sales services may differ.
Additionally, obtaining multiple estimates makes it easier to negotiate prices.
To request from your desired contractor at a lower price, we recommend obtaining estimates from multiple contractors.
When comparing estimates,
“Check the items in the estimate”
“Type of solar panel”
“Warranties and after-sales services”
and make a detailed comparison to make your judgment! If the quality of auxiliary materials is low or if steps are skipped, costs can be reduced, so avoid making decisions based solely on price!
▶ Go to “Breakdown of installation capacity, equipment, and construction costs” in this article
Check if they provide support for subsidy applications
Subsidies may be available for solar panel installations and battery installations, but if the order of procedures is incorrect or if there are deficiencies in the documents, the subsidy may not be granted.
There are systems that require personal applications and cannot be applied for by the contractor, as well as systems that require prior applications before installation, so it is reassuring to have a contractor who can support the preparation of necessary documents and the flow of procedures.
Complete the procedures specified for each system (for Tokyo’s subsidy, prior application before installation; for Inagi City’s subsidy, check the reception status as it is on a first-come, first-served basis) before proceeding with the construction!
In the case of subsidies in Tokyo, the process involves submitting a grant application and performance report after the completion of the work, which will be granted after a review. For subsidies in Inagi City, the application is made after the completion of the work! (The procedure varies depending on the system.)
▶ Go to “Subsidies and Grants that May Be Applicable in Inagi City” within this article
Benefits of Introducing Solar Power Equipment
The benefits of introducing solar panels are summarized in the following five points!
Benefit 1: Economic Benefits
The biggest advantage of introducing solar panels is the economic benefit!
Although the selling price of electricity has decreased compared to ten years ago, you can benefit by reducing the amount of electricity purchased from the utility by consuming the generated power yourself!
As electricity prices rise, the ability to cover your consumption with solar power becomes attractive!
If you plan to use the generated power at night, the installation of a storage battery is essential!
For residential (under 10kW) selling prices (FIT), the price setting from certifications after October 2025 will be “24 yen/kWh for the first four years, and 8.3 yen/kWh from the fifth to the tenth year.” The same price will apply for the 2026 fiscal year. After the fifth year, it is often more advantageous to use it at home (self-consumption) rather than selling it, so combining it with a storage battery is also an option.
👉 For purchase prices and periods, click here
Benefit 2: You can utilize subsidies!
The conditions and amounts of subsidies vary by prefecture and municipality, but if you meet the conditions, you may be able to utilize subsidies!
Reducing the actual burden amount through subsidies is a significant advantage!
In the case of Inagi City, there may be applicable systems from the national government, Tokyo, and Inagi City.
Benefit 3: Environmentally Friendly!
Solar power generation has low carbon dioxide emissions and can reduce dependence on fossil fuels, contributing to the mitigation of global warming.
Solar panels themselves do not produce noise or exhaust gases during the generation process, making them an environmentally friendly method of power generation. (However, devices such as power conditioners may have operational noise.)
Benefit 4: Heat Insulation Effect is Expected!!
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 expected heat insulation effects!
(Note that this does not improve the building’s insulation performance itself.)
Benefit 5 Electricity can be used even during power outages!!
If a storage battery is installed, it becomes 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 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 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 fixing methods for slate roofs and tile roofs vary by construction method, but when fixing hardware to the roofing material or substrate with screws, waterproofing of the fixed parts is crucial.
If the method involves making holes in the roof, the risk of leaks inevitably arises.
Of course, we will ensure proper waterproofing, but if you are concerned about making holes, 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 metal fittings 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, switching to 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.
It is not simply a matter of “this manufacturer has the best solar panels”; it is important to choose solar panels that are suitable for your life plan and building!
Here are some points to consider when comparing solar panels!
Choosing Method 1: Compare based on total output of the roof
When installing solar panels on the roof, it is important to consider how much power can be generated in a limited area, and generating more power is always better!
The size and output of solar panels vary by 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, there may be cases where “20 panels of 350W can be installed” and “15 panels of 400W can be installed,” leading to different numbers of panels that can be installed on the same roof due to size differences.
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 power generation amount (kWh) will vary depending on conditions such as roof orientation, slope, and shading.
Choosing Method 2: Compare based on degradation rate of solar panels
Solar panels have a degradation rate, and their output gradually decreases over 10 or 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.
By considering the degradation rate along with the initial output, you can choose solar panels without regrets!
Choosing Method 3: Compare based on 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!
A longer warranty is always better, 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 Inagi City
We have compiled frequently asked questions from customers considering the installation of solar panels and storage batteries in Inagi City. (Tap to open the answers)
How much does it cost to install solar panels and storage batteries in Inagi 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 published on the solar panel installation and storage battery installation pricing page. We will create a layout diagram from the blueprints and on-site survey and provide a free estimate!
Are there any subsidies available for solar power and storage battery installation in Inagi City?
As of October 7, 2026, Tokyo’s subsidies for solar power generation and storage batteries (Cool Net Tokyo) are accepting pre-applications. For storage batteries, only SII registered devices (registered products for Reiwa 8) will be eligible from pre-applications made after October 1, 2026. The “Carbon Neutral Housing Equipment Subsidy” in Inagi City has a reported application rate of 74.8% against the budget as of October 2, 2026, and will end as soon as the budget limit is reached on a first-come, first-served basis. 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 even after the construction is completed?
For many programs, procedures are required before construction. Tokyo’s subsidies require pre-application before installation, and if you install first, you will be ineligible. Inagi City’s subsidies allow applications after installation is complete, but they will end once the budget is reached on a first-come, first-served basis. Procedures differ by program.
Since the order of procedures varies by program, please confirm before signing a contract or starting construction.
Can solar panels be installed on slate roofs? I’m worried about leaks.
It is possible to install on slate roofs, but it is necessary to check the condition of the roofing material and substrate. The fixing method varies by construction method, and in methods that fix 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 suggest 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 within 10 to 20 years after installation, there will be additional costs for removing and reinstalling solar panels. If the remaining lifespan of the roof is short, renovating to a highly durable roofing material before installation may help reduce total costs.
Please consult us about the installation process after checking 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 of electricity will be 8.3 yen/kWh after the fifth year, making it more advantageous to use it in your home rather than selling it.
Additionally, the Tokyo Metropolitan Government’s subsidy for storage batteries is designed for simultaneous installation with solar panels, but you can also apply with 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 those 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.
In Inagi City, the shading from surrounding buildings and trees varies from house to house. You can check the expected power generation through the power generation simulation.
How long will the construction period take?
In the above construction example (solar panels 4.3 kW + storage battery), it took about 3 days. The duration may vary if roof work is done simultaneously or depending on the shape of the roof and installation capacity.
Additionally, please note that there will be a separate period for applying for subsidies and to the power company, so please consult us as soon as possible.
What is the current selling price (FIT)?
For residential use (under 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 provides financial simulations that take 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-service maintenance DM notices, and we visit customers who wish to have inspections. We can also clean solar panels with a special brush if the power generation decreases due to dirt.
Since the roof is a difficult area to check by yourself, 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 water heater removal pricing page.
If you are looking for a solar panel installation company in Inagi City, please consult Kakeru Koumuten
Our company handles a wide range of exterior renovations, including solar panels, roof work, and exterior wall work in Inagi City, Tokyo.
We have received requests from many customers, including renovation companies and real estate agencies, who have contacted us!
Kakeru Koumuten promises “high-quality renovations at low costs”, and we have received positive feedback from numerous 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 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 assist with small jobs like 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 with us!
Whether you want to “know recommended solar panels,” “keep costs as low as possible,” or “just get 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 be outdone by other companies in terms of cost, quality, and organization for 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 Inagi City, Tokyo, and Points for Solar Work
Inagi City, Tokyo, is located in the Tama region. The official page of Inagi City indicates the Tamagawa, Asakawa, Oguragawa, and Misawagawa rivers as flood-prone areas, and there are designated landslide hazard areas and special warning areas within the city.
Below are summarized points to consider regarding the residential environment of Inagi City and when installing solar panels and storage batteries. (Tap to open)
View the characteristics of Inagi City, Tokyo, and points for solar work
■ Check the installation locations of storage batteries and power converters against the hazard map
On the page for the flood risk areas in Inagi City, information is provided about the Tamagawa River (maximum expected rainfall: total rainfall of 588mm over 48 hours in the Tamagawa River basin), as well as the Asakawa, Oguragawa, and Misawagawa rivers, based on the flood risk areas announced by Tokyo Metropolitan Government in February 2024. The city’s disaster prevention map and hazard map includes flood hazard maps for the Tamagawa and Misawagawa rivers. When deciding where to install storage batteries and power conditioners, it is advisable to check the flood risk for your location on the hazard map and consider the height and position of the installation for peace of mind.
■ Check for landslide hazard area designations on sloped properties
Inagi City has designated landslide hazard areas and special hazard areas as of March 2019, and as of March 25, 2026, there are 278 hazard areas and 218 special hazard areas according to the official city page (most of which pertain to areas at risk of collapse due to steep slopes). If you are placing equipment such as storage batteries near sloped land or retaining walls, it is advisable to check the landslide hazard map and Tokyo’s “Landslide Hazard Warning Map” for any designations for peace of mind.
■ Tokyo’s annual sunshine hours are approximately 1,927 hours
According to the Japan Meteorological Agency’s average values (1991-2020), Tokyo’s annual sunshine hours are approximately 1,927 hours.
The amount of electricity generated varies by season, so it is important to conduct annual generation simulations and choose the capacity of storage batteries to match the times of high electricity usage.
■ Check for shadows from surrounding buildings and trees
In areas close to buildings or trees, the way shadows fall varies for each house depending on the roof’s direction and height. Since solar panels generate less electricity when shaded, Kakeru Koumuten creates layout diagrams based on the drawings and the actual site conditions, allowing you to confirm through generation simulations.
■ City subsidies are post-application and first-come, first-served. Tokyo requires pre-application
The subsidies from Inagi City require post-application after the completion of construction and installation, and are first-come, first-served, so applications will close once the budget is reached. On the other hand, the Tokyo subsidies (Cool Net Tokyo) require pre-application before installation. It is important to check the procedures and timelines for each system in advance, in conjunction with the timing of the construction.
■ For sloped sites or narrow roads, plan scaffolding and equipment delivery carefully
In areas with narrow front roads, sloped sites, or close proximity to surrounding buildings, careful planning of scaffolding and equipment delivery may be necessary. Kakeru Koumuten will respond to the site conditions with our own scaffolding team and our own scaffolding materials.
■ Check the roof condition according to the building’s age
For buildings that have been around for many years, it is important to check the condition of the roofing materials and substrate before installing solar panels. Depending on the roof’s condition, installing them simultaneously with roof renovations can help reduce future costs for removing and reinstalling solar panels.
Our company serves Kanagawa Prefecture and Tokyo, and we handle many exterior construction and solar power projects in Inagi 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 Inagi City, Tokyo
Kakeru Koumuten Co., Ltd. accepts requests throughout Kanagawa Prefecture and all of Tokyo.
Areas in Inagi City, Tokyo
Omaru, Inagi City / Oshitate, Inagi City / Koyodai, Inagi City / Sakahama, Inagi City / Nagamine, Inagi City / Higashinaganuma, Inagi City / Hirao, Inagi City / Hyakumura, Inagi City / Yanoguchi, Inagi City / Wakabadai, Inagi City
・For exterior wall painting in Inagi City, Tokyo, trust Kakeru Koumuten Co., Ltd.!
・For roof remodeling in Inagi City, Tokyo, trust Kakeru Koumuten Co., Ltd.!
・For exterior remodeling in Inagi City, Tokyo, trust Kakeru Koumuten Co., Ltd.!
・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 & Announcements
・Explaining the Importance of Comparing Estimates!
・Top 12 Solar Power Generation Manufacturers! Features and Selection Tips!
・What are the installation costs for solar power generation? Comprehensive tips to reduce costs!
・What are the best locations for installing solar power generation? Key points for site selection!
・Check out our 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!
