Leave Your Solar Panel Installation Work in Musashimurayama City, Tokyo to Kakeru Koumuten Co., Ltd.!
For solar panel and storage battery installation in
Musashimurayama City, Tokyo,
trust Kakeru Koumuten!
Kakeru Koumuten is a company specializing in exterior renovations.
As a company strong in roofing work, we are entrusted withsolar panel and storage battery installations considering roofing and waterproofing!
“How to choose a solar panel contractor in Musashimurayama City, Tokyo”
“Costs for solar panel and storage battery installation”
“Subsidies available for solar system installation in Musashimurayama City, Tokyo”
We will also explain the above three points!
Installing solar panels carries risks, such as“the occurrence of leaks” and other troubles.
To ensure a satisfactory 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 Musashimurayama City, Tokyo
- Roof Inspection Before Installing Solar Panels
- Possible Subsidies and Grants Available in Musashimurayama City, Tokyo
- Price List for Solar Panel and Storage Battery Installation
- Breakdown of Installation Capacity, Equipment, and Construction Costs
- Self-Estimate and Profit Simulation for Solar Power Generation
- Customer Testimonials
- Case Studies of Solar Panel Installations
- How to Choose a Solar Panel Installation Contractor in Musashimurayama City, Tokyo
- Benefits of Introducing Solar Equipment
- Points to Consider When Introducing Solar Power Generation
- How to Choose Solar Panels
- Frequently Asked Questions About Solar and Storage Battery Installation in Musashimurayama City, Tokyo
- If You Are Looking for a Solar Panel Installation Contractor in Musashimurayama City, Tokyo, Contact Kakeru Koumuten
- Characteristics of Musashimurayama City, Tokyo and Points for Solar Construction
- Service Area in Musashimurayama City, Tokyo
Reasons Why Kakeru Koumuten is Chosen for Solar Panel Installation in Musashimurayama City, Tokyo
Here are the reasons why our company is entrusted with solar panel installation by customers in Musashimurayama City, Tokyo.
“Our Unique Strengths in Solar Panel Installation That Cannot Be Imitated by Other Companies”
have received great acclaim from many customers.
Because we are confident, we welcome estimates from any number of companies!
1. We Can Also Handle Exterior Renovations Other Than Solar Panel Installation!
Problems such as leaks that occur with solar panel installation may be caused by insufficient checks on the roof and waterproofing at the installation site.
Even if one is knowledgeable about solar panels, there are cases where the roof and waterproofing at the installation site are outside their expertise, so caution is necessary.
It is reassuring to have expertise in roofing to avoid maintenance issues and troubles after installation!
Kakeru Koumuten is strong in roofing work and can also detach and attach solar panels in-house, allowing for quick responses to maintenance and urgent troubles after solar panel installation!
2.Facilities Specialized in Exterior Renovation
Kakeru Koumuten has organized the following warehouses and material storage areas to provide solar work and exterior renovations at low cost and high quality.
We have established five bases for material storage and showrooms.
In-house Ownership of Scaffolding Materials
To ensure safety during work on the roof, we own the scaffolding materials necessary for temporary scaffolding according to the construction conditions and can assemble scaffolding in-house.
By performing scaffolding work with our own scaffolding team instead of outsourcing, we can also cut costs for scaffolding work.
We own scaffolding materials for approximately 50 single-family homes!
Even if there are height differences on the site, our in-house scaffolding team will plan the scaffolding according to the local conditions.
Storage of Materials in Our Large Warehouse
We store roofing materials and paints, and we can also store removed solar panels.
By ordering a large quantity of materials at once, you canpurchase materials at a lower cost!
Additionally, we always have a stock of roofing materials, allowing us torespond quickly in emergencies!
Sorting and Transporting Waste Materials In-House
The installation of solar panels often involves roofing work, generating various waste materials such as paints, wood, and metal.
By sorting and recycling waste materials, we can significantly cut waste disposal costs.
Exterior Remodeling Dedicated Showroom
In the showroom, we not only hold meetings but also
allow you to check the actual foundation brackets for solar panels and see how they are installed on roofing materials!
We can also provide simulations of potential earnings and installation costs if you decide to introduce solar panels!
Since roofing and exterior wall work often accompany each other, we also have samples of roofing materials and models that explain the structure, allowing for detailed explanations!
3.All Work Performed by Our Own Team
One of Kakeru Koumuten’s major strengths is its complete in-house construction.
By having a consistent system from inquiry to project completion, Kakeru Koumuten can provide high-quality roof renovations at reduced costs.
Additionally, one representative will handle everything from the estimate to project completion.
Since the same person will manage the sales and construction, 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 permits for the construction industry and for the collection and transportation of industrial waste!
We also have nationally certified sheet metal workers and painting specialists on staff, and we are confident in our construction techniques.
We can also handle large-scale roofing projects such as factories!
5. Warranty and Aftercare
In addition to the manufacturer’s warranty for solar panel installation, we also provide our own construction warranty (leakage warranty)!
(The construction warranty for solar panel installation is 10 years. Depending on the condition of the roof before installation, we may not be able to provide a warranty unless a roof renovation is performed. The construction warranty is separate from the manufacturer’s product warranty, and the coverage and conditions vary based on the warranty details.)
Aftercare is available annually, and we send out reminder DM each year.
If you have questions about the warranty, please click on the image above!
6. Flexible and Prompt Response
Our company is equipped to handle various roofing troubles and situations.
If you cannot access the roof due to height, we can utilize drones to assist!
During leak investigations, we can also conduct inspections using a thermal imaging camera.
If the power generation of the solar panels decreases due to dirt, we can provide cleaning services using specialized brushes.
We will respond according to the customer’s wishes.
7. Human Resource Development
To improve skills, we create various roof models and conduct practical training.
Since the construction methods vary depending on the shape and slope of the roof, we regularly provide technical training so that each staff member can handle various cases.
8. Creation of Easy-to-Understand Materials and Simulations
Kakeru Koumuten provides not only “estimates,” “layout diagrams,” and “power generation simulations” but also a “solar construction guidebook” and “profit and loss simulations” that take into account loan interest rates and electricity costs.
Profit and loss simulations can be created for projected cumulative profits and losses over 20 to 30 years.
Even customers who are not familiar with solar construction will receive materials that clearly summarize 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 or 30 years.
Confirming “Is it okay to install directly on the current roof?” before installation is the key point to prevent leaks and unnecessary expenses!
Kakeru Koumuten, which specializes in roofing work, has summarized the items to check before installation.
| 1. Types of Roofing Materials and Age | The fixing method varies depending on the roofing material, such as slate, tiles, metal roofs, and flat roofs (roof waterproofing). If the remaining lifespan of the roofing material is short, we may suggest a 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 power generation. We will create a layout diagram from the drawings and the site, and you can check the power generation simulation. |
| 4. Shape of the Roof and Usable Area | The shape and size of the roof determine the number of panels that can be installed (installation capacity). The number of panels that can be installed varies depending on the panel size, so we will compare based on the total output of the roof. |
| 5. Fixing Method and Waterproofing Details | We will confirm whether the method involves drilling holes in the roofing material for fastening or using brackets to secure the roofing material. The fixing method varies by technique, so please check the waterproofing treatment method for the fixed parts during the estimate. |
| 6. Weight of the Roof | The roof will become heavier due to the panels. After investigating the existing roof, substrate, and load-bearing capacity, switching to lighter roofing materials may be an option if necessary. |
| 7. Installation Location of Equipment and Wiring | We will check the installation location of the power conditioner and storage battery, as well as the wiring route to the distribution board. The length of the wiring also affects costs. |
| 8. Ease of Scaffolding Setup and Delivery Routes | If there are elevation differences on the site, planning for scaffolding and the delivery routes for equipment and materials may require some ingenuity. We will also check the width of the front road and any steps on the site during the on-site survey. |
Fixing Methods and Checkpoints by Roofing Material
| Roof Material | Main Fixing Method | Pre-Installation Check Points |
|---|---|---|
| Slate Roof | Varies by method (e.g., fixing brackets to the roof material and substrate with screws) | Waterproof treatment of fixing parts, cracks or deterioration of slate, condition of the substrate. If deterioration is advanced, consider roof overlay (cover method) or replacement first. |
| Tile Roof | Fixed with brackets and methods suitable for the type of tile (even methods that do not drill holes in the tiles will fix to the substrate) | Type and condition of tiles, substrate, load-bearing capacity. Depending on the investigation results, there may be methods to replace with lightweight roofing materials before installation. |
| Metal Roof (Horizontal and Vertical) | Fixed with catch-type brackets that grip the 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 frame | Type and deterioration status of the waterproof layer, waterproofing around the frame. Consider in conjunction with the timing of waterproofing work. |
If you renovate the roof 10 to 20 years after installation, there will be additional costs for removing and re-installing solar panels. If the roof is deteriorating, it may be more cost-effective in the long run to renovate to a highly durable roofing material before installation.
Kakeru Koumuten Co., Ltd. specializes in roofing work and can also handle the removal and re-installation of solar panels in-house, so please consult us according to the condition of your roof!
▶ Click here for roof renovation in Musashimurayama City, Tokyo
PossibleSubsidies and Grants
If you introduce solar panels or storage batteries in Musashimurayama City, Tokyo, there is a possibility that the systems of “the national government,” “Tokyo,” and your residence “Musashimurayama City” may apply.
The following information is based on the official pages of each system as of October 7, 2026. The acceptance status may change depending on the budget, so please check the latest information before contracting or starting work.
Eligibility Conditions and Application Period for Subsidy Programs
| Program | Main Eligibility Conditions | Subsidy Amount | Application Period & Status |
|---|---|---|---|
| Tokyo “Household Solar Power Generation Promotion Project” | Individuals, corporations, or management associations installing unused solar power systems (under 50kW output, JET certification, etc.) in residential properties within Tokyo. The generated power must be used in the residential part. Pre-application is required. | Existing homes: 15,000 JPY per kW for up to 3.75 kW (maximum 450,000 JPY), 12,000 JPY/kW for over 3.75 kW and under 50 kW. New homes: 12,000 JPY/kW for up to 3.6 kW (maximum 360,000 JPY), 10,000 JPY/kW for over 3.6 kW. |
For the fiscal year 2026, pre-applications are being accepted from May 29 (will end once the budget is reached). From the pre-applications for fiscal year 2026, submission of certificates issued by financial institutions will be mandatory at the time of performance reporting. |
| Tokyo “Household Storage Battery Promotion Project” | Owners of eligible equipment (storage batteries registered with SII, excluding national and local governments). Must be installed between April 1, 2026, and March 30, 2027. If applying after October 1, 2026, only products registered with the national SII for fiscal year 2026 are eligible. | Storage battery package: 100,000 JPY per kWh (maximum 1,200,000 JPY per household). Additional for participating in DR demonstration (100,000 JPY per unit; 150,000 JPY per unit if energy management equipment is installed). Expansion of storage battery units: 60,000 JPY/kWh (maximum 720,000 JPY per household). |
For the fiscal year 2026, pre-applications are being accepted from May 29. Grant applications and performance reports will be accepted from June 30. |
| Musashimurayama City “Zero Carbon City Housing Promotion Subsidy” (Fiscal Year 2026) | Residents registered in Musashimurayama City who install and own unused solar power systems or home storage batteries between April 1, 2026, and January 31, 2027, are eligible. There must be no tax arrears, and the same type of equipment must not have received city subsidies in the past. Properties mandated to install solar power under the Tokyo Environmental Protection Ordinance are excluded. | Solar power: 20,000 JPY per kW for local businesses (maximum 70,000 JPY), 15,000 JPY/kW for businesses outside the city (maximum 50,000 JPY). Home storage batteries: 15,000 JPY/kW for local businesses (maximum 50,000 JPY), 10,000 JPY/kW for businesses outside the city (maximum 30,000 JPY). *Amounts under 1,000 JPY will be rounded down. |
From April 1, 2026 (Wednesday) to February 1, 2027 (Monday). Ends once the budget limit is reached. As of October 2, 2026, the remaining budget is reported to be 2,666,000 JPY on the city’s official page (updated October 5, 2026). |
| National “DR Household Storage Battery Project” (Fiscal Year 2025 Supplement) | Newly introducing household storage systems that can be utilized for DR (demand response) with registered products. | Calculated based on a standard amount of 345,000 JPY per initial effective capacity of 1 kWh (subsidy rate within 30% and maximum 600,000 JPY per application). | The budget was reached on May 29, 2026, and the public recruitment has ended (the official site states there are no plans to reopen recruitment, and 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 construction work such as insulation renovations of windows (openings) and the building structure; installation of storage batteries alone cannot be applied for. Solar panels are not included as eligible facilities. | Storage Battery: 96,000 JPY/unit | Applications will close once the budget limit is reached. As of October 5, 2026, the official site shows that the application amount for renovations is 8% of the budget. Please check the official site for the application status. |
The Tokyo solar and storage battery subsidy program requires prior application. For storage batteries applied for after October 1, 2026, only products registered with the national SII will be eligible, and the equipment requirements will change. The subsidy in Musashimurayama City has a set installation period (April 1, 2026 – January 31, 2027) and application deadline (February 1, 2027), and will close once the budget limit is reached. Eligibility conditions, application procedures, and the possibility of combining with other programs vary by system, and applying does not guarantee funding, so please confirm before contracting or starting work.
At Kakeru Koumuten, we will guide you on the eligibility conditions and application periods for each program after confirming them.
National Subsidy “DR Home Storage Battery Project (Support Project for the Introduction of Home Storage Systems for DR Resource Implementation)”
The national government has been implementing the “DR Home Storage Battery Project” to support the installation of home storage batteries.
This program targets those who are newly introducing registered storage systems that can be utilized for demand response (DR), and in the fiscal year 2025 supplementary budget, the subsidy amount was determined based on a standard amount of 34,500 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 that items contracted or ordered before the grant decision are not eligible.
However, the fiscal year 2025 supplementary budget applications reached the budget on May 29, 2026, and the public offering has ended. The official site also states that there are no plans to reopen the public offering, and applications are currently not possible. Please check the official site for future public offerings.
Furthermore, there are currently no subsidies confirmed for the installation of solar panels on existing homes.
👉 Click here for the DR Home Storage Battery Project official site
Tokyo “Home Solar Power Generation Promotion Project”
This subsidy is for those who install unused solar power generation systems in residential homes within Tokyo. The simultaneous installation of storage batteries is not a condition.
●Existing Homes: For systems below 3.75 kW, 150,000 JPY per kW (maximum 450,000 JPY); for systems over 3.75 kW and below 50 kW, 120,000 JPY per kW
●New Homes: For systems below 3.6 kW, 120,000 JPY per kW (maximum 360,000 JPY); for systems over 3.6 kW and below 50 kW, 100,000 JPY per kW
●Additional amounts are available for rooftop installations and waterproofing work.
The target is to install unused panels with an output of less than 50 kW that have obtained JET certification, for use in residential areas. The process involves prior application followed by a grant application after installation, and starting from the fiscal year 2026 prior application, submission of proof issued by financial institutions during the performance report has become mandatory.
According to the official page of Tokyo, pre-registration is being accepted from May 29, 2026. It will end once the budget is reached, so please check the official page for the registration status.
👉 Here is the official page of Tokyo (Cool Net Tokyo)
Tokyo’s “Household Battery Installation Promotion Project”
This is a subsidy for the installation costs of battery systems aimed at increasing self-consumption of electricity generated by solar power and improving energy independence during emergencies.
●Battery package: 100,000 JPY per kWh (up to 1,200,000 JPY per household)
●Additional for participating in DR demonstration: 100,000 JPY per unit (150,000 JPY per unit if energy management equipment is installed)
●Expansion of battery units: 60,000 JPY per kWh (up to 720,000 JPY per household)
Eligible applicants are owners of the subsidized equipment (excluding national and local governments), and the installation must be completed between April 1, 2026, and March 30, 2029. If pre-registration is done after October 1, 2026, only products registered with the national SII for the fiscal year 2026 will be eligible.
The official page of Tokyo states that pre-registration is being accepted from May 29, 2026. For detailed information, including conditions for combining with solar power generation, please check the official page.
👉 Here is the official page of Tokyo (Cool Net Tokyo)
Musashimurayama City “Zero Carbon City Housing Promotion Subsidy” (Fiscal Year 2026)
This subsidy is for residents registered in Musashimurayama City who install unused solar power systems or home batteries in eligible housing between April 1, 2026, and January 31, 2027, and own them. Eligible housing includes individual residences (owned or rented), mixed-use buildings where the residential part occupies more than half of the total floor area, and owned apartment buildings. It is also a requirement that there are no tax delinquencies and that the same type of equipment has not received subsidies in the past for the same housing. Housing where the installation of solar power generation is mandated by the Tokyo Environmental Protection Ordinance is not eligible.
●Solar power generation system: 20,000 JPY per kW for local businesses (up to 70,000 JPY), 15,000 JPY per kW for non-local businesses (up to 50,000 JPY)
●Home batteries: 15,000 JPY per kW for local businesses (up to 50,000 JPY), 10,000 JPY per kW for non-local businesses (up to 30,000 JPY)
●Amounts calculated under 1,000 JPY will be rounded down
Applications will be accepted from April 1, 2026 (Wednesday) to February 1, 2027 (Monday) (weekdays from 8:30 AM to 5:15 PM), and applications can be submitted at the city office, by mail, or electronically. If the budget limit is reached, applications will close, and the official page of the city states that as of October 2, 2026, the budget amount is 9,850,000 JPY, with a remaining budget of 2,666,000 JPY (updated on October 5, 2026).
It is stated on the city’s official page that it is possible to combine this with subsidies from the national government and Tokyo Metropolitan Government. The same subsidies also cover heat-insulating painting work and insulation work. For details on eligibility conditions and application procedures, please check the official page.
👉 Musashimurayama City “Reiwa 8 Zero Carbon City Housing Promotion Project Subsidy” is here
👉 Subsidy application method for solar power generation systems and home storage batteries is here
Solar Panel Installation & Storage Battery Installation Price List
⇧Service Menu | For costs related to solar panel removal and hot water heater removal, click here
Breakdown of Installation Capacity, Equipment, and Construction Costs
It is important to check the costs of solar panels and storage batteries by separating them into “equipment costs (device costs)” and “construction costs.”
Even for the same “solar panel installation set,” the amount can vary significantly depending on the installation capacity, equipment grade, and roof condition.
Considerations for Installation Capacity (kW) and Battery Capacity (kWh)
The installation capacity of solar panels is determined by “output of one panel (W) × number of panels”, with the unit being kW (kilowatt). Storage batteries are compared in terms of the amount of electricity they can store, represented in kWh (kilowatt-hour).
The amount of kW that can be placed on the roof varies for each house depending on the roof 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 panels as approximately 800,000 JPY to 1,200,000 JPY for 3 to 5 kW, and 1,200,000 JPY to 1,900,000 JPY for 6 to 10 kW. (These are just approximate amounts and can vary based on wiring length, scaffold range, existing roofing materials, panel layout, etc.)
▶ Installation Menu | Costs for Solar Panel Installation and Storage Battery Installation
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 each company’s estimate!
| 1. Solar Panels | Manufacturer, model number, output of one panel (W), number of panels, total installation capacity (kW) are written. |
| 2. Power Conditioner | Manufacturer, model number, capacity, number of units, installation location (indoor/outdoor). Also check if it is a type that controls together with the storage battery. |
| 3. Storage Battery | Manufacturer, model number, capacity (kWh), range usable during power outages (entire house or specific circuits), installation location. |
| 4. Mounting Frame and Hardware | Name of the hardware suitable for the roofing material and the method of fixing (whether it is a method that drills holes or a method that grips and secures). |
| 5. Wiring and Electrical Work | Wiring route and length, work around the distribution board, presence of a monitor to check power generation. |
| 6. Roof Reinforcement and Waterproofing | Details of waterproofing treatment for fixed parts, whether necessary roof repairs and substrate reinforcements are included. |
| 7. Applications | How much support is included for applications to the power company, certification applications for selling electricity (FIT), and subsidy applications. |
| 8. Scaffolding | Scope and quantity of scaffolding. If it is simultaneous with roof work or exterior painting, check that the same scope and quantity are not double-counted. |
| 9. Removal and Disposal | Whether the removal of existing solar thermal water heaters or old panels and disposal costs for waste materials are included. |
| 10. Tax Classification and Warranty | Whether it is tax-inclusive or tax-exclusive, conditions under which additional costs may arise, and details and duration of manufacturer and workmanship warranties. |
If the capacities are different, both the price and the power generation will change. Kakeru Koumuten Co., Ltd. warmly welcomes comparative estimates, so if you bring estimates from other companies, we will explain the differences item by 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 the solar panels on the roof and the capacity of the storage battery, you can get an approximate estimate and profit simulation!
*The simulation results are approximate. Actual profits may vary based on assumptions such as electricity rates, self-consumption ratios, selling prices, and costs for equipment inspection 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)!
Case Studies of Solar Panel Installation
| Construction Details |
| Solar Panel Installation Battery Installation |
| Existing Roofing Material |
| Horizontal Metal Roof (Super Galtect) |
| Installation Capacity |
| Solar Panel: 4.3kW Battery: 5kWh |
| Base Mounting Hardware Used |
| Niigata Manufactured Aluminum Catch Type Hardware |
| Fixing Method & Waterproofing Arrangement |
| Fixed 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 there are grants 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 the solar panels on the roof.
Since we can also determine the installation capacity, it allows for power generation simulations and financial simulations.
We have understood the expected grant amount, so we explained it to the customer along with the estimate!
How to Choose a Solar Panel Installation Contractor in Musashimurayama City, Tokyo
There are many solar panel installation contractors available in Musashimurayama City, Tokyo, and you may be unsure which contractor to choose.
Therefore, when requesting solar panel installation and battery storage installation work, let’s confirm the following four points.
● Have extensive knowledge not only about solar panels but also about roofs
● Confirm the existence of warranties and aftercare services
● Obtain estimates from multiple contractors (three companies as a guideline)
● Check if they provide support for subsidy applications
By confirming the above four points, you will be able to choose a reliable contractor.
Have knowledge not only about solar panels but also about roofs
Improper installation of solar panels can be caused by a lack of knowledge and verification regarding roofs and waterproofing.
While knowledge about solar panels is certainly important, understanding the roof and waterproofing at the installation site of the solar panels is also crucial.
⚠︎Examples of troubles caused by insufficient verification of roofs and waterproofing
・Solar panels installed on a deteriorated roof causing leaks
・Solar panels installed on a roof with a short lifespan, requiring removal and renovation within a few years
・Misjudging the type of waterproofing and applying incorrect treatment, 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 unexpected troubles.
▶ Go to “Roof Verification Before Installing Solar Panels” in this article
Confirm the existence of warranties and aftercare services
When choosing a solar installation contractor, let’s confirm the existence of warranties. It is important to check not only the duration of the warranty but also the coverage, exclusions, and cost conditions.
While the solar panels and battery storage come with a manufacturer’s warranty, it is also important to check for the existence of a workmanship warranty in case leaks occur after installation!
For contractors that offer a workmanship warranty, if leaks occur after installation within the warranty period and conditions, they may cover the repairs under the warranty.
Additionally, some contractors provide aftercare services separate from warranties, so make sure to check if the contractor you are considering has aftercare services.
Since abnormalities or damages on the roof may not be visible, you might not notice them yourself.
By conducting inspections during aftercare, you can detect abnormalities early, making it easier to prevent major repairs or breakdowns!
Kakeru Koumuten Co., Ltd. offers a rain leak guarantee as part of the workmanship warranty for solar panel installations. (The warranty for solar panel installations is 10 years, and depending on the condition of the roof before installation, we may not be able to provide a warranty without performing roof renovations.)
We also conduct aftercare maintenance and send out annual DM!
If you check the DM and wish to proceed, we will visit for aftercare 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 with the same manufacturer and the same construction details, costs and warranties or after-sales services may differ.
Additionally, obtaining multiple estimates makes it easier to negotiate prices.
To request your preferred contractor at a lower price, we recommend obtaining estimates from multiple contractors.
When comparing estimates,
“Check the estimate items”
“Type of solar panels”
“Warranties and after-sales services”
and carefully compare them to make a decision! Avoid judging solely based on cost, as using lower-grade materials or skipping processes can reduce costs!
▶ Go to “Breakdown of installation capacity, equipment, and construction costs” within this article
Confirm 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 grant may not be awarded.
Since there are systems like the Tokyo subsidy that require prior application, it is reassuring to have a contractor that supports the preparation of necessary documents and the flow of procedures.
Complete the procedures specified for each system (for the Tokyo subsidy, prior application) before proceeding with the construction!
For the Tokyo subsidy, after installation, you will need to submit a grant application and performance report, which will be reviewed before the grant is awarded! (The flow of procedures varies by system)
Benefits of Introducing Solar Equipment
The benefits of introducing solar panels are as follows!
Benefit 1: Economic Benefits
The biggest advantage of introducing solar panels is the economic benefit!
The selling price of electricity has decreased compared to ten years ago, but by consuming the electricity generated, you can reduce the amount of electricity purchased from the utility company and gain benefits!
As electricity costs rise, the ability to cover your power consumption with solar power becomes appealing!
If you plan to use the generated electricity at night, installing a storage battery is essential!
For residential use (under 10kW), the selling price (FIT) from certifications after October 2025 is set at “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 fiscal year 2026. After the fifth year, it is often more advantageous to use it at home (self-consume) rather than sell it, making the combination with a storage battery a viable option.
👉 Ministry of Economy, Trade and Industry | For purchase prices and periods, click here
Advantage 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 through subsidies is a significant advantage!
In the case of Musashimurayama City, you may be eligible for programs from the national government, Tokyo, and Musashimurayama City. The application deadline for Musashimurayama City’s subsidy is February 1, Reiwa 9, and it will end once the budget limit is reached (please check the remaining budget on the city’s official page).
Advantage 3 Environmentally friendly!
Solar power generation has low carbon dioxide emissions and can reduce dependence on fossil fuels, contributing to the mitigation of global warming.
Solar panels themselves do not produce noise or exhaust gases during the generation process, making them an environmentally friendly method of power generation. (However, devices such as power conditioners do have operational noise.)
Advantage 4 Heat insulation effects are expected!!
By installing them on the roof or rooftop, the panels block direct sunlight from hitting the roof.
Especially in summer, it can help reduce the temperature of the roof, providing expected heat insulation effects!
（This does not improve the insulation performance of the building itself）
Benefit 5: Electricity can be used even during power outages!!
If a storage battery is installed, it is possible to use electricity even during emergencies such as power outages!
Even without a storage battery, if you have a power conditioner with autonomous operation capability, you may be able to use electricity from a dedicated outlet during daytime power generation.
（The devices, output, and duration that can be used during a power outage vary depending on the model and wiring method）
What points should be noted when introducing solar power generation?
Next, we will explain the “three points to note” when installing solar panels!
Point 1: Maintenance costs can be incurred
A particularly overlooked maintenance cost is for the roof where solar panels are installed.
If you perform roof remodeling 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 remodel 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 consider maintenance costs in the simulation 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 at the fixed points becomes crucial.
If the method involves making holes in the roof, there will inevitably be a risk of leaks.
Of course, we will ensure proper waterproofing, but if you are concerned about making holes, replacing the roofing material with a metal roof and securing the solar panels using the catch method is also an option. (The catch method has compatibility conditions between the roofing material and the fasteners, and cannot be used with all metal roofs)
Catch-type base hardware for horizontal metal roofs
Note 3: The roof will become heavier
Since solar panels will be installed, the roof will become heavier. After investigating the existing roof, substrate, and load capacity, replacing it with a lighter roof may also be an option if necessary.
How to Choose Solar Panels?
There are many manufacturers of solar panels, and their output and costs vary.
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 electricity can be generated in a limited area, and the more electricity generated, the better!
Solar panels come in various sizes and outputs depending on the manufacturer.
A panel with an output of 350W and a panel with an output of 400W may seem that the higher output panel is better at first glance.
However, if the size of the panel does not fit well with the roof, “20 panels of 350W can be installed, while only 15 panels of 400W can be installed,” meaning the number of panels that can be installed may differ even on the same roof due to the size of the panels.
400W × 15 panels = 6kW (total output of the roof)
350W × 20 panels = 7kW (total output of the roof)
As shown above, even if the output of a single panel is lower, the total output of the roof may be higher!
It is important to consider the total output of the roof rather than the output of a single panel!
*The above is the calculation of total output (kW). The actual electricity generation (kWh) will vary depending on conditions such as the orientation, slope, and shading of the roof.
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 electricity generation itself.
Choosing solar panels by considering the degradation rate, rather than just the initial output, will lead to a more satisfactory choice!
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!
It’s always better to have a longer warranty, so let’s check the warranty periods and conditions of the manufacturers you are considering!
Frequently Asked Questions about Solar Power and Storage Battery Installation in Musashimurayama City, Tokyo
We have compiled frequently asked questions from customers considering the installation of solar panels and storage batteries in Musashimurayama City, Tokyo. (Tap to open the answers)
How much does it cost to install solar panels and storage batteries in Musashimurayama City, Tokyo?
The cost varies depending on the installation capacity, equipment, and roof condition. In the above construction example (solar panel 4.3kW + storage battery, completed in April 2025), it was 2.2 million yen to 2.3 million yen.
Guidelines by capacity are available on the solar panel installation and storage battery installation pricing page. We will create a layout diagram from the drawings and on-site survey and provide a free estimate!
Are there any subsidies available for solar power and storage battery installation in Musashimurayama City, Tokyo?
As of October 7, 2026, Tokyo’s “Promotion Project for Solar Power Generation in Households” (for existing homes, 15,000 yen per kW for up to 375,000 yen) and “Promotion Project for Storage Battery Installation in Households” (100,000 yen per kWh for up to 1,200,000 yen per household) are accepting pre-applications starting May 29, 2026, as listed on the official page of Tokyo (Cool Net Tokyo). In Musashimurayama City, there is a subsidy for the Zero Carbon City Housing Promotion Project (for fiscal year 2026, for local businesses, 20,000 yen per kW for solar power up to 70,000 yen, and 15,000 yen per kW for household storage batteries up to 50,000 yen), which is accepting applications until February 1, 2027, and will end once the budget limit is reached, as stated on the official page of Musashimurayama City. The national DR household storage battery project has ended its public recruitment.
Since the application status may change, please refer to the subsidy and grant section and consult with us before signing a contract.
Can I apply for subsidies after the construction is completed?
This varies by program. Tokyo’s subsidies require pre-application, and Musashimurayama City’s grants have specified installation periods (from April 1, 2026, to January 31, 2027) and application deadlines (February 1, 2027). Conditions such as whether you can contract and start construction before applying may differ by program, so please confirm before signing a contract.
The order of procedures varies by program, so please check before signing a contract and starting construction.
Can solar panels be installed on a slate roof? I’m worried about leaks.
It is possible to install on a slate roof, but it is necessary to check the condition of the roofing material and substrate. The fixing method varies by construction method, and when fixing brackets to the roofing material and substrate, waterproofing treatment of the fixed parts is crucial.
Kakeru Koumuten Co., Ltd. is a specialized exterior renovation company strong in roofing work, so we will check the condition of the roof before installation. 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, it may be more cost-effective to renovate to high-durability roofing materials before installation.
Please consult us on how to proceed with the installation after checking the condition of the roof during the on-site survey!
Should I install a storage battery together with the solar panels?
If you want to use the generated electricity at night or prepare for power outages, simultaneous installation is recommended. The selling price for electricity will be 8.3 yen/kWh after the fifth year, making it more advantageous to use it in your home rather than selling it.
Additionally, the Tokyo Metropolitan Government’s subsidy for storage batteries (for Reiwa 8, it is 100,000 yen per kWh, with a maximum of 1.2 million yen per household) aims to increase self-consumption of electricity generated by solar power. The subsidy program in Musashimurayama City also includes home storage batteries. You can compare “solar only” and “solar + storage battery” in a financial simulation.
How many kW can I install on my roof? Is it okay for north-facing roofs or roofs with shadows?
The capacity that can be installed varies depending on the shape, orientation, and size of the roof. At Kakeru Koumuten, we create a layout diagram from the drawings and on-site survey, and we will present the installation capacity and power generation simulation.
Musashimurayama City has the Sayama Hills extending east-west in the northern part, with a gently sloping terrain to the south. The shape and orientation of the roof, as well as the shadows cast by surrounding buildings, will differ for each house. You can check the expected power generation through the power generation simulation.
How long will the construction period be?
For the above construction example (solar panel 4.3 kW + storage battery), it took about 3 days. The duration may vary if roofing work is done simultaneously or depending on the shape of the roof and installation capacity.
Please note that there will be additional time required for applications for subsidies and power companies, so please consult us early.
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 quickly in the first 4 years and then focus on self-consumption. Kakeru Koumuten provides a financial simulation that takes into account loan interest rates and electricity prices.
Can you handle maintenance and inspections after installation?
Yes, we can. Kakeru Koumuten sends out annual after-maintenance DM notices and visits customers who wish to have inspections. We can also clean solar panels with a special brush if the power generation decreases due to dirt.
It is difficult to check areas on the roof by yourself, so please feel free to consult us if you have any concerns.
Can you also renovate roofs that already have solar panels installed?
It is possible. Kakeru Koumuten Co., Ltd. can detach and reattach solar panels in-house, allowing us to perform roof overlay (cover method) or re-roofing after removing the panels, and we will handle everything consistently until reinstallation. The removed panels can be stored in our own warehouse.
For costs, please refer to the solar panel detachment and hot water heater removal pricing page.
If you are looking for a solar panel installation contractor in Musashimurayama City, Tokyo, please consult Kakeru Koumuten
Our company handles many exterior renovations, including solar panel installation, roof work, and exterior wall work in Musashimurayama City, Tokyo.
We have received requests from many customers, including renovation companies and real estate agencies!
Kakeru Koumuten promises “high-quality renovations at low costs”, and we have received positive feedback from numerous customers.
We continue to update our annual construction performance, and we will strive to improve quality to satisfy even more customers in the future.
Our company can perform all exterior renovations, not only roof overlay (cover method) and re-roofing but also partial roof repairs, exterior painting, and exterior wall cover methods.
We are also happy to handle small jobs such as partial repairs and rain gutter cleaning!
In urgent cases such as leak repairs, we may be able to provide emergency measures without setting up scaffolding, as long as safety can be ensured, so please consult us!
“I want to know recommended solar panels”, “I want to keep costs down as much as possible”, “I just want an estimate for now”, we will provide optimal solutions for specific requests.
We will never propose unnecessary work focused on profit!
We always stand in the customer’s position and 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 estimates!
Estimates are completely free, and if we are found to be inferior to other companies, you are free to decline!
Characteristics of Musashimurayama City, Tokyo and Points of Solar Work
Musashimurayama City is located in the northern central part of Tokyo, covering an area of 15.32 square kilometers, measuring 5.20 kilometers east to west and 4.65 kilometers north to south. The northern part features the Sayama Hills, which extend east to west, gently sloping down to the south where residential areas and farmland spread out, as stated on the city’s official page. We have summarized the characteristics of the terrain in Musashimurayama City, Tokyo, and points to consider when installing solar panels and storage batteries below. (Tap to open)
View the characteristics of Musashimurayama City, Tokyo, and points for solar installation
■ The terrain slopes gently down to the south from the Sayama Hills. Check the elevation differences and tree shadows on-site near the hills.
In the terrain that slopes down from the hills, the elevation differences of the site, the step differences with the front road, and the width and slope of the road may vary by location. It may be necessary to devise the scaffolding setup and the transportation routes for panels and storage batteries, and in homes close to the greenery of the hills, the shadows cast by surrounding trees can differ from house to house. At Kakeru Koumuten, our own scaffolding team plans the scaffolding to match the site, creates layout diagrams from the drawings and on-site surveys, and you can confirm this through power generation simulations.
■ Check the flood risk areas of the Zambori River and Soribori River and be cautious about the installation locations of equipment.
According to the city’s official page, the flood inundation risk areas for the Zambori River and Soribori River were designated by Tokyo on February 15, Reiwa 8 (2026), and the rainwater inundation risk areas were designated on March 31 of the same year. The update of the hazard map reflecting these will be conducted within the Reiwa 8 fiscal year. Additionally, maps based on the sediment disaster warning areas and special warning areas designated by Tokyo in Reiwa 1 (2019) are also published. Depending on where the power conditioner and storage battery are installed, separate from the panels on the roof, the impact during flooding may vary. Please check the assumptions for your location on the city’s hazard map and consult about the installation location and height in conjunction with the installation conditions of the manufacturer you will use.
■ The types and ages of roofs vary from house to house. Check the roof and waterproofing before installation.
Even within the same city, the types of roofs, their ages, and the shapes of the sites vary from house to house. The capacity that can be installed and the fixing methods also change depending on the shape and orientation of the roof and the materials used. At Kakeru Koumuten, we will confirm the type and condition of the roof and the situation of the site before installation, and propose fixing methods, waterproofing arrangements, and scaffolding plans.
■ The annual sunshine hours at the Tokyo Observatory are about 1,927 hours.
According to the Japan Meteorological Agency’s average values (1991-2020), the annual sunshine hours at the Tokyo Observatory are about 1,927 hours, with January (about 193 hours) being the most and June during the rainy season (about 124 hours) being the least. (This is a reference value, not an observation value within Musashimurayama City.)
The power generation amount in Musashimurayama City can also change due to shadows from surrounding buildings and trees, so conducting annual power generation simulations and selecting the capacity of the storage battery to match the times of high electricity usage are key points.
Our company handles many exterior construction and solar installation projects in Musashimurayama 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 Musashimurayama City, Tokyo
Kakeru Koumuten accepts requests throughout Kanagawa Prefecture and all of Tokyo.
List of Areas in Musashimurayama City, Tokyo
Inahira, Musashimurayama City / Enoki, Musashimurayama City / Ominami, Musashimurayama City / Gakuen, Musashimurayama City / Kishi, Musashimurayama City / Zambori, Musashimurayama City / Shinmei, Musashimurayama City / Chuo, Musashimurayama City / Nakato, Musashimurayama City / Nakahara, Musashimurayama City / Honmachi, Musashimurayama City / Mitsuki, Musashimurayama City / Mitsufuji, Musashimurayama City / Midorigaoka, Musashimurayama City
・Trust Kakeru Koumuten for exterior wall painting in Musashimurayama City, Tokyo!
・Trust Kakeru Koumuten for roof renovations in Musashimurayama City, Tokyo!
・Trust Kakeru Koumuten for exterior renovations in Musashimurayama City, Tokyo!
・Kakeru Koumuten Co., Ltd. construction achievements
・Kakeru Koumuten Co., Ltd. after maintenance
・Kakeru Koumuten Co., Ltd. construction menu and price list
・Kakeru Koumuten Co., Ltd. staff blog and announcements
・Explaining the importance of comparative 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!
・Here are the estimates for solar power generation!
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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!
