Leave Your Solar Panel Installation Work in Inagi City, Tokyo to Kakeru Koumuten Co., Ltd.!
For solar panel and storage 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 storage battery installation considering roofing and waterproofing!
“How to Choose a Solar Panel Contractor in Inagi City”
“Costs for Solar Panel and Storage 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 you have no regrets about your solar panel installation, we recommend obtainingestimates from about three companies!
Table of Contents (tap to open/close)
- Reasons why Kakeru Koumuten is chosen for solar panel installation in Inagi City, Tokyo
- Roof inspection before installing solar panels
- Possible subsidies and grants available in Inagi City
- Price list for solar panel installation and battery installation
- Breakdown of installation capacity, equipment, and construction costs
- Self-estimation and financial simulator for solar power generation
- Customer testimonials
- Examples of solar panel installation projects
- How to choose a solar panel installation company in Inagi City, Tokyo
- Benefits of introducing solar equipment
- Points to be aware of when introducing solar power generation
- How to choose solar panels
- Frequently asked questions about solar and 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 points for solar construction
- 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 include
One reason is that “Kakeru Koumuten serves Kanagawa Prefecture and Tokyo as its service area”,
“Our unique strengths in solar panel installation that cannot be imitated by other companies” have also 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 can also handle exterior renovations other than 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 may be cases where the roof and waterproofing at the installation site are outside your expertise, so caution is necessary.
It is reassuring to have expertise in roofing to avoid maintenance issues and troubles after installation!
Kakeru Koumuten Co., Ltd. is strong in roofing work and can also detach and attach solar panels in-house, allowing for quick responses to maintenance and urgent troubles after solar panel installation!
2.Facilities Specialized in Exterior Renovation
Kakeru Koumuten Co., Ltd. has organized the following warehouses and material storage areas to provide low-cost, high-quality solar work and exterior renovations.
We have established five bases centered around Yokohama City, Kanagawa Prefecture for material storage and showrooms.
In-house Scaffolding Materials
To ensure safety during work on the roof, we own the scaffolding materials necessary for temporary scaffolding according to construction conditions and can assemble scaffolding in-house.
By not outsourcing scaffolding work and using our own scaffolding team, we can also cut costs for scaffolding work.
We own scaffolding materials for approximately 50 houses!
In Inagi City, our in-house 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, you can purchase materials at a lower cost!
Additionally, we always have a stock of roofing materials, so we can respond quickly in emergencies!
In-house sorting and transportation of waste materials
The installation of solar panels often involves roofing work, generating various waste materials such as paints, 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 roofing materials!
We can also provide simulations for potential earnings and installation costs when introducing solar panels!
Since roofing and exterior wall work often accompany each other, we also have samples of roofing materials and models that explain the structure, allowing for detailed explanations!
3.All work performed by our own team
One of Kakeru Koumuten’s major strengths is its complete in-house construction.
By having Kakeru Koumuten handle everything from inquiries to project completion in a consistent manner, we can keep costs down and provide high-quality roof renovations.
Additionally, one representative will assist you from the estimate to the completion of the work.
Since the same person will handle sales and construction management, smooth communication is possible.
We can provide consistent in-house construction from temporary scaffolding installation, exterior wall painting, to roof renovations!
4. Various Permits and Skilled Workers
We have obtained construction industry licenses and permits for industrial waste collection and transportation!
We also have nationally certified sheet metal and painting technicians, and we are confident in our construction skills.
We can also handle large-scale roof projects such as factories!
5. Warranty and Aftercare
In addition to the manufacturer’s warranty for solar panel installation work, we also provide our own construction warranty (leakage warranty)!
(The construction warranty for solar panel installation is 10 years. Depending on the condition of the roof before installation, we may not be able to provide a warranty unless a roof renovation is performed. The construction warranty is separate from the manufacturer’s product warranty, and the scope and conditions vary based on the warranty details.)
Aftercare is available annually, and we send out notification DM each year.
If you have questions about the warranty, please click on the image above!
6. Flexible and Prompt Response
Our company is equipped to handle various roofing troubles and situations.
If you are unable to access the roof due to height, we can utilize drones to assist!
During leak investigations, we can also conduct surveys using a thermal imaging camera.
If the power generation of solar panels decreases due to dirt, we can also provide cleaning with a specialized brush.
We will respond according to your wishes.
7. Human Resource Development
To improve skills, we create various roofing models and conduct practical training.
Since the construction methods change depending on the shape and slope of the roof, we regularly conduct technical training to ensure that each staff member can handle various cases.
8. Creation of Easy-to-Understand Materials and Simulations
Kakeru Koumuten provides not only “estimates,” “layout diagrams,” and “power generation simulations” but also a “solar construction guidebook” and a “profit and loss simulation” that takes into account loan interest rates and electricity costs.
The profit and loss simulation can be created for projected cumulative profits and losses over 20 to 30 years.
Even customers who are not familiar with solar construction will receive easy-to-understand materials that include points to consider and disadvantages!
We encourage you to obtain comparative estimates and compare them with other companies’ plans!
Roof Inspection Before Installing Solar Panels
Once solar panels are installed, they will remain on the roof for 20 or 30 years.
Confirming “Is it okay to install them directly on the current roof?” before installation is the key point to prevent leaks and unnecessary expenses!
Kakeru Koumuten, which specializes in roofing work, has summarized the items to check before installation.
| 1. Types of Roofing Materials and Age | The fixing method varies depending on the roofing material, such as slate, tiles, metal roofs, and flat roofs (roof waterproofing). If the remaining lifespan of the roofing material is short, we may suggest roof renovation first. |
| 2. Condition of Substrate and Waterproof Sheet | If the sheathing 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 the amount of electricity generated. We will create a layout diagram from the drawings and the site, and you can confirm it with a power generation simulation. |
| 4. Shape of the Roof and Installable Area | The number of panels that can be installed (installation capacity) is determined by the shape and size of the roof. Since the number of installable panels varies depending on the panel size, we will compare based on the total output of the roof. |
| 5. Fixing Method and Waterproofing Details | We will check whether the method involves drilling holes in the roofing material for fastening or using brackets to secure the roofing material. The fixing method varies by technique, so please confirm the waterproofing treatment method for the fixing parts during the estimate. |
| 6. Weight of the Roof | The roof will become heavier due to the panels being added. After investigating the existing roof, substrate, and load-bearing capacity, switching to lighter roofing materials may also be an option if necessary. |
| 7. Installation Location of Equipment and Wiring | We will confirm the installation location of the power conditioner and storage battery, as well as the wiring route to the distribution board. The length of the wiring will also affect costs. |
Fixing Methods and Checkpoints by Roofing Material
| Roof Material | Main Fixing Method | Pre-Installation Check Points |
|---|---|---|
| Slate Roof | Varies by method (e.g., fixing brackets to roof material and substrate with screws) | Waterproof treatment of fixing parts, cracks or deterioration of slate, condition of substrate. If deterioration is advanced, consider roof overlay (cover method) or replacement first. |
| Tile Roof | Fixed with brackets and methods suitable for the type of tile (even methods that do not drill holes in the tiles will secure to the substrate) | Type and condition of tiles, substrate, load-bearing capacity. Depending on the investigation results, there may be methods to replace with lightweight roofing material before installation. |
| Metal Roof (Horizontal and Vertical) | Fixed with catch-type brackets that grip the roofing material (depends on the combination of roofing material and brackets) | Whether the roofing material and brackets are compatible, installation conditions from the roofing material manufacturer. If compatible, methods that do not drill holes may be available. |
| Flat Roof / Rooftop | Fixed by installing a frame | Type and deterioration status of the waterproof layer, waterproofing around the frame. Consider in conjunction with the timing of waterproofing work. |
If you plan to renovate the roof 10 to 20 years after installation, there will be additional costs for removing and reinstalling solar panels. If the roof is deteriorating, renovating to a highly durable roofing material before installation may help reduce costs in the long run.
Kakeru Koumuten Co., Ltd. is strong 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
PossibleSubsidies and Grants in Inagi City, Tokyo
When introducing solar panels or storage batteries in Inagi City, Tokyo, there is a possibility of being eligible for programs from “the national government,” “Tokyo,” and “Inagi City.”
The following information is based on official pages of each program as of October 7, 2026. The application status may change due to budget and recruitment periods, so please check the latest information before contracting or starting work.
Eligibility Conditions and Application Timing for Subsidy Programs
| Program | Main Eligibility Conditions | Subsidy Amount | Application Period & Status |
|---|---|---|---|
| Tokyo “Reiwa 8 Year Household Solar Power Generation Promotion Project” (Cool Net Tokyo) | New installation of certified solar modules in residential properties or their premises within the city, with a system under 50kW. Pre-application before installation is required. | Existing homes: 150,000 JPY/kW for 3.75kW or less (maximum 450,000 JPY), 120,000 JPY/kW for over 3.75kW New homes: 120,000 JPY/kW for 3.6kW or less (maximum 360,000 JPY), 100,000 JPY/kW for over 3.6kW (Additional costs for mounting frames, waterproofing work, and renovation defect insurance, etc.) |
Pre-application: From May 29, 2026 Grant application and performance report: From June 30, 2026 to March 30, 2029 |
| Tokyo “Reiwa 8 Year Household Storage Battery Promotion Project” (Cool Net Tokyo) | New installation of storage batteries in residential properties within the city, and must be SII registered equipment. This project is intended for simultaneous installation with solar power, but applications can be made for storage batteries alone. Pre-applications after October 1, 2026 will only be eligible for SII registered products for Reiwa 8. | Storage battery package: 100,000 JPY/kWh (maximum 1,200,000 JPY per household) Storage battery unit expansion: 60,000 JPY/kWh (maximum 720,000 JPY per household) (Additional incentives for participating in DR demonstrations, etc.) |
Pre-application: From May 29, 2026 Grant application and performance report: From June 30, 2026 |
| Inagi City “Carbon Neutral Housing Equipment Subsidy” Reiwa 8 Year | Homeowners within the city must have been residing there prior to application, and must not have any delinquent personal resident taxes. Post-application after completion of construction/installation is required, and items installed between March 1, 2026 and February 28, 2027 are eligible. Buyers of new homes that have installed eligible equipment are also eligible. | 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 reports that 74.8% of the budget amount has been applied for. Applications will close 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 an initial effective capacity of 34,500 JPY per kWh (subsidy rate within 3/10; maximum 600,000 JPY per application). | As of May 29, 2026, the budget has been reached, 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 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 applied for after the completion of construction and installation, known as post-application, and 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 requirements for eligible 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. Since the procedures differ by program, please confirm before contracting or starting construction.
Kakeru Koumuten Co., Ltd. will guide you on the eligibility conditions for each program after confirming them.
Tokyo “Reiwa 8 Fiscal 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 yen/kW for systems up to 3.75kW (maximum 450,000 yen), and 120,000 yen/kW for systems exceeding 3.75kW. Additionally, there are extra items such as mounting frame installation, 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 Fiscal Year Household Storage Battery Promotion Project”
Tokyo is also providing subsidies for newly installed storage batteries in residential homes. The subsidy amounts are 100,000 yen per kWh for storage battery packages (maximum 1,200,000 yen per household), and 60,000 yen per kWh for additional storage battery units (maximum 720,000 yen 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 fiscal year SII registered product list will be eligible. This program is intended for simultaneous installation with solar power, but applications can also 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 in their homes. The subsidy amount for the Reiwa 8 fiscal year is 20,000 yen per kW for solar power generation equipment (maximum 80,000 yen), and a flat 40,000 yen for storage battery systems. Eligible applicants are homeowners residing in the city prior to application, with no delinquency on individual resident taxes, among other conditions. Buyers of newly constructed homes that have introduced 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 on a first-come, first-served basis once the budget limit is reached. Applications will be made through the LoGo form (electronic application). As of October 2, 2026, the official city page reports that the application rate against the budget amount is 74.8%. Please check the official page for the requirements and necessary documents for eligible equipment.
👉 Here is the official page of Inagi City (Reiwa 8 Carbon Neutral Housing Equipment Subsidy)
National Subsidy “DR Home Storage Battery Project (Support Project for Home Storage Systems for DR Resource Introduction)”
The government has been implementing the “DR Home Storage Battery Project” to support the installation of home storage batteries.
This project targets those who are newly introducing registered storage systems that can be utilized for demand response (DR). In the fiscal year 2025 supplementary project, the subsidy amount is 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 conditions such as exclusions for contracts or orders made before the grant decision.
However, the fiscal year 2025 supplementary applications reached the budget on May 29, 2026, and the public recruitment has ended (the previous fiscal year 2024 supplementary applications also ended 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 Storage Battery Project
Solar Panel Installation & Storage Battery Installation Price List
⇧Service Menu | For Costs of Solar Panel Removal and Water Heater Dismantling, Click Here
Breakdown of Installation Capacity, Equipment, and Construction Costs
The costs for solar panels and storage batteries should be checked separately as “Equipment Costs (Device Costs)” and “Construction Costs”.
Even for the same “Complete Solar Panel Installation,” the amount can vary significantly depending on the installation capacity, equipment grade, and roof condition.
Understanding 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 (kilowatt). Storage batteries are compared based on the amount of electricity they can store, expressed in kWh (kilowatt-hour).
The amount of kW that can be installed on a roof varies for each house based on the roof’s shape, orientation, and size. At Kakeru Koumuten, we create layout diagrams from blueprints and on-site surveys to present the installation capacity.
On our pricing page, we list solar panel costs as approximately 800,000 JPY to 1,200,000 JPY for 3 to 5 kW, and 1,200,000 JPY to 1,900,000 JPY for 6 to 10 kW. (These are just rough estimates and can vary based on wiring length, scaffold range, existing roofing materials, panel layout, etc.)
▶ Service Menu | For Costs of Solar Panel Installation and Storage Battery Installation, Click Here
Items to Check in 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) are listed. |
| 2. Power Conditioner | Manufacturer, model number, capacity, number of units, installation location (indoor/outdoor). Also check if it is a type that controls with a battery. |
| 3. Battery | Manufacturer, model number, capacity (kWh), range usable during a power outage (whole house or specific circuits), installation location. |
| 4. Mounting Frame and Hardware | Name of the hardware suitable for the roofing material and the method of securing it (whether it is a method that drills holes or a method that clamps and secures). |
| 5. Wiring and Electrical Work | Wiring route and length, work around the distribution board, presence of a monitor to check power generation. |
| 6. Roof Reinforcement and Waterproofing | Details of waterproofing treatment at the fixing points, whether necessary roof repairs and substrate reinforcements are included. |
| 7. Application | How much support is included for applications to the power company, certification applications for selling electricity (FIT), and subsidy applications. |
| 8. Scaffolding | Scope and quantity of scaffolding. If roof work and exterior painting are done simultaneously, check that the same scope and quantity are not counted twice. |
| 9. Removal and Disposal | Whether the removal of existing solar thermal water heaters and old panels, as well as disposal costs for waste materials, are included. |
| 10. Tax Classification and Warranty | Whether it is tax-inclusive or tax-exclusive, conditions under which additional costs may arise, details and duration of manufacturer warranty and workmanship warranty. |
If the capacity differs, both the price and power generation will change. Kakeru Koumuten Co., Ltd. welcome comparisons, so if you bring estimates from other companies, we will explain the differences for each item!
Self-Estimate and Profit Simulation for Solar Power Generation
With the simulator above,
you can obtain an approximate estimate and a profit simulation for up to 30 years!
If you know the total installation capacity of solar panels on the roof and the capacity of the battery, you can obtain an approximate estimate and profit simulation!
*The simulation results are approximate. Actual profits may vary based on assumptions such as electricity rates, self-consumption ratios, selling prices, and costs for equipment inspection or 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)!
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 class |
| Base Mounting Hardware Used |
| Niigata Manufactured / Aluminum Catch Type Hardware |
| Fixing Method & Waterproofing Details |
| Fixed with catch type hardware gripping the horizontal metal roof (Catch Method) |
| Price Range |
| 2,200,000 JPY～2,300,000 JPY *Due to the grant being provided, the actual burden amount is approximately 1,000,000 JPY Expected recovery period for construction costs: about 8 to 9 years (self-consumption) *The grant amount and recovery estimate are based on the system and calculations at the time of construction, and may differ under the current system. |
| Construction Period |
| 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 will be provided. |
Our Proposal
We visited to provide an estimate and created a layout diagram for the solar panels from the drawings!
The layout diagram shows the arrangement of solar panels when placed on the roof.
Since we can also determine the installation capacity, it allows for power generation simulations and financial simulations.
We have also understood the expected amount of the grant, so we explained it to the customer along with the estimate!
How to Choose a Solar Panel Installation Contractor in 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 battery storage installation work, let’s check the following 4 points.
● Not only knowledge of solar panels but also extensive knowledge of roofs
● Confirm the existence of warranties and aftercare services
● Obtain estimates from multiple contractors (3 companies is a guideline)
● Check if they provide support for subsidy applications
By confirming the above 4 points, you will be able to choose a reliable contractor.
Knowledge of roofs as well as solar panels
Defective installation of solar panels can be caused by a lack of knowledge and verification regarding roofs and waterproofing.
While knowledge of 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 installed on a severely deteriorated roof causing leaks
・Solar panels installed on a roof with a short lifespan, requiring renovations for removal and reinstallation within a few years
・Misjudging the type of waterproofing and incorrect processing 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 Verification Before Installing Solar Panels” in this article
Confirm the existence of warranties and aftercare services
When choosing a solar installation contractor, let’s confirm the existence of warranties. It is important to check not only the number of years but also the scope of coverage, disclaimers, and cost conditions.
While solar panels and battery storage come with manufacturer warranties, also check for the existence of workmanship warranties in case leaks occur after installation!
For contractors that offer workmanship warranties, if leaks occur after installation, they may be able to respond under the warranty, provided it is within the warranty period and conditions.
Additionally, some contractors offer after-service separate from warranties, so be sure to check if the contractor you are considering has after-service.
Changes or damages on the roof may occur in areas that are not visible, so there is a possibility that customers may not notice them.
By conducting inspections during after-maintenance, we can check the invisible areas and more easily detect any anomalies early, preventing major repairs or failures!
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 roof renovation is performed.)
We also conduct after-maintenance and send out DM every year!
Please check the DM, and if you wish, we will visit you for after-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-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 estimate items”
“Type of solar panel”
“Warranties and after-services”
and make detailed comparisons to make your judgment! If the rank of auxiliary materials is low or if processes 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
There may be subsidies available for solar panel installations and battery installations, but if the order of procedures is incorrect or if there are deficiencies in the documents, the subsidy may not be granted.
Some systems require personal applications and cannot be applied for by the contractor, and some require pre-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 subsidy, pre-application before installation; for Inagi City’s subsidy, check the reception status as it is first-come-first-served) 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 process occurs after the completion of the work! (The procedure may vary depending on the system.)
▶ Go to “Subsidies and Grants Available in Inagi City” within this article
Benefits of Introducing Solar Power Equipment
The benefits of introducing solar panels are as follows!
Benefit 1: Economic Advantage
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 electricity you buy from power companies by consuming the electricity you generate!
As electricity prices rise, the ability to cover your consumption with solar power becomes more attractive!
If you plan to use the generated electricity at night, installing a storage battery is essential!
Furthermore, the selling price (FIT) for residential use (under 10kW) will be set at “24 yen/kWh for the first 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 at home (self-consumption), making the combination with a storage battery a viable option.
👉 For purchase prices, periods, etc., visit the Agency for Natural Resources and Energy
Benefit 2: You Can Utilize Subsidies!
The conditions and amounts of subsidies vary by prefecture and municipality, but if you meet the requirements, you may be able to utilize subsidies!
Reducing the actual burden amount through subsidies is a significant advantage!
In the case of Inagi City, you may be eligible for programs from the national government, Tokyo, and Inagi City.
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 like power conditioners may have operational noise.)
Benefit 4: Expect Heat Insulation Effects!!
By installing the panels on the roof or rooftop, they block direct sunlight from hitting the roof.
Especially in summer, this 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 like power outages!
Even without a storage battery, if you have a power conditioner with autonomous operation capabilities, you may be able to use electricity from a dedicated outlet during daytime generation.
(The devices, output, and duration that can be used during a power outage vary depending on the model and wiring method.)
What points should be noted when introducing solar power generation?
Next, we will explain the “three points to note” when installing solar panels!
Point 1 Maintenance costs can be incurred
A particularly overlooked maintenance cost is for the roof where 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 the deterioration of the storage battery.
It would be reassuring to request a simulation considering 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 using screws or other fasteners to secure the roofing material and substrate, waterproofing of the fixed areas becomes 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, 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.)
Base metal fittings for horizontal metal roofs
Note 3: The roof will become heavier
Installing solar panels will make the roof heavier. After investigating the existing roof, substrate, and load capacity, switching to a lighter roof may be one 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 Point 1: Compare by Total Output of the Roof
When installing solar panels on the roof, it is important to consider how much power can be generated in a limited area, and generating more power is always better!
Solar panels come in various sizes and outputs depending on the manufacturer.
A panel with 350W output and a panel with 400W output may seem that the one with higher output 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 installation capacities 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 Point 2: Compare by Degradation Rate of Solar Panels
Solar panels have a degradation rate, and their output gradually decreases over 10 years and 20 years.
The degree of output reduction after long-term use varies by product. The manufacturer’s output warranty value is a standard figure for guarantees and does not represent 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 Point 3: Compare by Warranty Period
There are several types of warranties for solar panels, including “output warranty,” “natural disaster warranty,” and “system warranty,” and the warranty periods vary by manufacturer.
For output warranties, some manufacturers offer a 30-year warranty while others offer a 10-year warranty, so it varies!
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 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 case study (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 and storage battery installation pricing page. We will create a layout diagram from the drawings and 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 (products registered in Reiwa 8) are 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 once 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 subsidies and grants 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. 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 vary by program.
Please confirm the order of procedures before signing a contract or starting construction, as they differ by program.
Can solar panels be installed on a slate roof? I’m worried about leaks.
Installation on a slate roof is possible, but it requires checking the condition of the roofing material and substrate. The fixing method varies by construction method, and for methods that fix brackets to the roofing material or substrate, waterproofing treatment of the fixed parts is essential.
Kakeru Koumuten 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 or replacement if deterioration is advanced.
The roof is old. Should I do a roof renovation first?
It depends on the condition of the roof. If a roof renovation is needed after 10 to 20 years of installation, the cost for removing and reinstalling solar panels will be incurred separately. If the remaining lifespan of the roof is short, renovating with highly durable roofing materials before installation may help reduce the total cost.
Please consult us about the installation process after confirming the condition of the roof through a site survey!
Should I install a storage battery together with the solar panels?
If you want to use the generated electricity at night or prepare for power outages, simultaneous installation is recommended. The selling price for electricity will be 8.3 yen/kWh after the fifth year, making it more advantageous to use it in your home rather than selling it.
Additionally, the Tokyo Metropolitan Government’s subsidy for storage batteries is designed for simultaneous installation with solar panels, but applications can also be made for storage batteries alone. You can compare “solar panels only” and “solar panels + storage battery” through a financial simulation.
How many kW can be installed on my roof? Is it okay for north-facing roofs or roofs with shadows?
The capacity that can be installed varies depending on the shape, orientation, and size of the roof. At Kakeru Koumuten, we create a layout diagram based on the drawings and site survey, and we will provide you with the installation capacity and power generation simulation.
In Inagi City, the shading caused by surrounding buildings and trees differs from house to house. You can check the expected power generation through the power generation simulation.
How long will the construction period be?
In the above construction example (solar panels 4.3 kW + storage battery), it took about 3 days. The duration may vary if roof work is done simultaneously or depending on the roof shape and installation capacity.
Additionally, please note that there will be a separate period for applications for subsidies and electricity companies, so please consult us as soon as possible.
What is the current selling price (FIT)?
For residential use (less than 10 kW), from the certification after October 2025, the first 4 years will be 24 yen/kWh, and from the 5th to the 10th year, it will be 8.3 yen/kWh, and the same price will apply for the 2026 fiscal year.
The idea is to recover the initial costs more quickly in the first four years and then focus on self-consumption. At Kakeru Koumuten, we provide a financial simulation that takes into account loan interest rates and electricity costs.
Can you handle maintenance and inspections after installation?
Yes, we can. Kakeru Koumuten sends out annual aftercare maintenance notices via DM and visits customers who wish for inspections. We can also clean solar panels using a special brush if the power generation decreases due to dirt.
It can be difficult to check areas on the roof by yourself, so please feel free to consult us if you have any concerns.
Can you also handle renovations for roofs that already have solar panels installed?
Yes, we can. Since Kakeru Koumuten can remove and reinstall solar panels in-house, we will handle the process of removing the panels, performing the roof overlay (cover method) or re-roofing, and reinstalling them consistently. The removed panels can be stored in our warehouse.
For information on costs, please see the solar panel removal and water heater removal pricing page.
If you are looking for a solar panel installation contractor in Inagi City, please consult Kakeru Koumuten
Our company handles many exterior renovations, including solar panels, roof work, and exterior wall work in Inagi City, Tokyo.
We receive requests from many customers, including renovation companies and real estate agencies, who have contacted us!
Kakeru Koumuten promises “high-quality renovations at low cost”, and we have received great feedback from numerous customers.
We continue to update our construction achievements every year and will strive to improve quality to satisfy even more customers in the future.
Our company can perform all exterior renovations, not only roof overlay work and re-roofing but also partial roof repairs, exterior painting, and cover methods for exterior walls.
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 a quote for now”, we will provide optimal solutions for your specific requests.
We will never propose unnecessary work that prioritizes profit!
We always stand in the customer’s position and will propose the best construction plan!
We are confident that we will not lose in terms of cost, quality, and planning for exterior work compared to other companies!
We are confident, so we welcome competitive quotes!
Estimates are completely free, and if our company is found to be inferior to others, you are free to decline!
Characteristics of 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.
We have summarized the housing environment of Inagi City and points to consider when installing solar panels and storage batteries below. (Tap to open)
View the characteristics of Inagi City, Tokyo, and points for solar work
■ Check the installation locations for storage batteries and power conditioners against the hazard map
On the page for the flood risk areas in Inagi City, information is provided about the Tama River (maximum expected rainfall: total rainfall of 588mm over 48 hours in the Tama River basin), as well as the Asakawa, Oguragawa, and Misawagawa rivers, based on the flood risk areas published by Tokyo Metropolitan Government in February 2024. The city’s disaster prevention map and hazard map includes flood hazard maps for the Tama River and Misawagawa River. When deciding on the installation location for storage batteries and power conditioners, it is advisable to check the flood risk for your residence on the hazard map and consider the height and position of the installation for peace of mind.
■ Confirm the designation of sediment disaster warning areas for properties facing slopes
In Inagi City, the Tokyo Metropolitan Government designated sediment disaster warning areas and special warning areas in March 2019. As of March 25, 2026, the official city page states there are 278 warning areas and 218 special warning areas (most related to landslides in steep slope areas). If placing equipment such as storage batteries near sloped land or retaining walls, it is advisable to check the sediment disaster hazard map and Tokyo’s “sediment disaster warning map” for 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.
Power generation varies by season, so it is important to conduct annual power generation simulations and select the capacity of storage batteries to match the times of high electricity usage.
■ Check for shadows from surrounding buildings and trees
In locations close to buildings or trees, the way shadows fall varies for each house depending on the roof’s orientation and height. Since solar panels generate less power when shaded, Kakeru Koumuten creates layout diagrams based on blueprints and the actual site conditions, allowing you to confirm through power generation simulations.
■ City subsidies are post-application and on a first-come, first-served basis. Tokyo requires pre-application
The subsidies from Inagi City are post-application after the completion of construction and installation, and are on a first-come, first-served basis, so applications will close once the budget is reached. On the other hand, the Tokyo Metropolitan Government’s subsidies (Cool Net Tokyo) require pre-application before installation. It is important to check the procedures and periods for each system in advance, in conjunction with the timing of 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 for scaffolding and equipment delivery may be necessary. Kakeru Koumuten will respond to the site conditions with our own scaffolding team and scaffolding materials.
■ Check the roof condition according to the age of the building
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 condition of the roof, installing them simultaneously with roof renovations can help reduce future costs for removing and re-installing 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 about 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
・Trust Kakeru Koumuten for exterior wall painting in Inagi City, Tokyo!
・Trust Kakeru Koumuten for roof renovations in Inagi City, Tokyo!
・Trust Kakeru Koumuten for exterior renovations in Inagi City, Tokyo!
・Kakeru Koumuten Co., Ltd. construction achievements
・Kakeru Koumuten Co., Ltd. aftercare services
・Kakeru Koumuten Co., Ltd. construction menu and price list
・Kakeru Koumuten Co., Ltd. staff blog and announcements
・Explaining the importance of comparison estimates and key points!
・Top 12 solar power generation manufacturers! Features and selection tips included!
・What are the installation costs for solar power generation? Comprehensive tips to reduce costs!
・What are the best locations for solar power installation? Key points for site selection included!
・Find out more about solar power generation estimates here!
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contact Kakeru Koumuten Co., Ltd.
Kakeru Koumuten is a young company whose team is, on average, in their late twenties, but our skills are second to none.
Our greatest strength is that we handle scaffolding, roofing and painting entirely in-house. In an industry where these tasks are usually divided among contractors, our complete service simplifies project management and helps keep costs down. Above all, if a problem arises, we respond promptly.
We proudly describe ourselves as the youngest and most helpful renovation company in Kanagawa!
