Leave Your Solar Panel Installation Work in Fujisawa City, Kanagawa Prefecture to Kakeru Koumuten Co., Ltd.!
For Solar Panel and Battery Installation in
Fujisawa City,
trust Kakeru Koumuten!
Kakeru Koumuten is a company specializing in exterior renovations based in Kanagawa Prefecture.
As a company strong in roofing work, we are entrusted withsolar panel and battery installation considering roofing and waterproofing!
“How to Choose a Solar Panel Contractor in Fujisawa City”
“Costs for Solar Panel and Battery Installation”
“Subsidies Available for Solar System Installation in Fujisawa City”
We will also explain the above three points!
Installing solar panels carries risks, such as“the occurrence of leaks” and other troubles.
To ensure a satisfactory solar panel installation, we recommend obtainingthree estimates!
Table of Contents (tap to open/close)
- Reasons Why Kakeru Koumuten is Chosen for Solar Panel Installation in Fujisawa City
- Roof Inspection Before Installing Solar Panels
- Possible Subsidies and Grants Available in Fujisawa City
- Pricing 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 Fujisawa City
- 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 Fujisawa City
- If You’re Looking for a Solar Panel Installation Contractor in Fujisawa City, Contact Kakeru Koumuten
- Characteristics of Fujisawa City and Points for Solar Installation
- Service Area in Fujisawa City
Reasons Why Kakeru Koumuten is Chosen for Solar Panel Installation in Fujisawa City
Regarding why our company is entrusted with solar panel installation by customers in Fujisawa City,
“Our Unique Strengths in Solar Panel Installation That Cannot Be Imitated by Other Companies”
have received high praise 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!
Issues 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 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 and issues 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 issues 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 necessary scaffolding materials for temporary scaffolding based on construction conditions and can assemble scaffolding in-house.
By not outsourcing scaffolding work and using our own scaffolding team, we can also cut costs associated with 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, we canpurchase materials at a lower cost!
Additionally, we always have a stock of roofing materials, allowing us torespond quickly in emergencies!
Sorting and Transporting Waste Materials In-House
The installation of solar panels often involves roofing work, generating various waste materials such as paint, wood, and metal.
By sorting and recycling waste materials, we can significantly cut waste disposal costs.
Exterior 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 attached to the roofing materials!
We can also provide simulations of the revenue and installation costs when introducing solar panels!
Since roofing and exterior wall work often accompany each other, we also have samples of roofing materials and models that explain the structure, allowing for detailed explanations!
3.All Work Performed by Our Own Team
One of Kakeru Koumuten’s major strengths is its complete in-house construction.
By having a consistent system from inquiry to project completion, Kakeru Koumuten can provide high-quality roof renovations at reduced costs.
Additionally, one representative will handle everything from the estimate to project completion.
Since the same person will manage the sales and construction aspects, smooth communication is ensured.
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 specialists on staff, giving us confidence 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 roof renovations are 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 every year, 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.
Even if you cannot access the roof at high altitudes, we can respond using a drone!
During leak investigations, we can also conduct surveys using a thermal imaging camera.
If the power generation of your solar panels decreases due to dirt, we can also provide cleaning services with a specialized brush.
We will respond according to your preferences.
7. Human Resource Development
To improve skills, we create various roof models and conduct practical training.
Since the construction methods vary depending on the shape and slope of the roof, we regularly provide technical training so that each staff member can handle various cases.
8. Creation of Easy-to-Understand Materials and Simulations
Kakeru Koumuten provides “estimates,” “layout diagrams,” and “power generation simulations,” as well as “Solar Installation Guidebooks” 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 installations 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) under the roofing material is damaged, it will affect the fastening strength and waterproofing. We will also check for any signs of leaks. |
| 3. Orientation, Slope, and Shadows of the Roof | The orientation and slope of the roof surface, as well as shadows from neighboring houses, trees, and utility poles, will affect the power generation. We 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 Usable 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 panels that can be installed 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 fixing or using brackets to secure the roofing material. The fixing method varies by technique, so please confirm the waterproof treatment method for the fixing 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 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. |
| 8. Ease of Scaffolding Setup and Delivery Routes | If there is a height difference on the site, planning for scaffolding and the delivery routes for equipment and materials may require some ingenuity. We will also check the width of the front road and any steps on the site during the on-site survey. |
Fixing Methods and Confirmation Points 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 suited to the type of tile (even methods that do not drill holes in the tiles will fix to the substrate) | Type and condition of tiles, substrate, load-bearing capacity. Depending on the investigation results, there may be methods to replace with lightweight roofing material before installation. |
| Metal Roof (Horizontal/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 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, 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 reinstallation of solar panels in-house, so please consult us according to the condition of your roof!
▶ Click here for roof renovations in Fujisawa City
PotentialSubsidies and Grants in Fujisawa City, Kanagawa Prefecture
If you are introducing solar panels or storage batteries in Fujisawa City, there is a possibility that you may be eligible for programs from the “National Government,” “Kanagawa Prefecture,” and “Fujisawa City”.
The following information is based on the official pages of each program as of October 6, 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 |
|---|---|---|---|
| Fujisawa City “Subsidy for Installation Costs of Residential Solar Panels, etc.” (Residential Solar Power Generation System, Lithium-ion Storage Battery) | Subsidy project for fiscal year Reiwa 8 published on the city’s official page. Applications cannot be accepted if there are tax delinquencies. Construction must begin after receiving the grant decision notification. The restriction period is 10 years for solar power and 6 years for storage batteries. Can be combined with national and prefectural subsidies (separate application required). | Solar Power: 15,000 JPY per kW of maximum output (up to 50,000 JPY) Storage Battery: 50,000 JPY per case |
According to the city’s official page (updated September 28, 2026), solar power (90 cases) closed on June 29, and storage batteries (150 cases) closed on July 28 after reaching the planned number. Applications are currently not accepted. |
| Kanagawa Prefecture “Fiscal Year Reiwa 8 Subsidy for Introduction of Residential Solar Power Generation and Storage Batteries” | To simultaneously introduce solar power generation and storage systems in residential buildings (houses with seismic performance). Applications must be made by the individual, and construction should start after the grant decision. | Solar Power: 70,000 JPY per kW Storage Battery: 150,000 JPY per unit |
Phase 1: May 11, 2026 – June 30, 2026 Phase 2: Starts September 7, 2026 (first-come, first-served) Applications reached the budget amount on September 7, 2026, and acceptance has been closed. Please check the prefecture’s official page for future recruitment. |
| National “DR Home Storage Battery Project” (Fiscal Year 7 Supplement) | Newly introduce home storage systems that can be utilized for DR (demand response) with registered products. | Calculated based on an initial effective capacity of 1 kWh at 34,500 JPY (subsidy rate within 30% and a maximum of 600,000 JPY per application). | The budget was reached on May 29, 2026, and the public recruitment has ended. (The official site states that there are no plans to reopen public 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 works such as insulation renovation of windows (openings) and the structure; applications cannot be made for just the installation of storage batteries. Solar panels are not included as eligible facilities. | Storage Battery: 96,000 JPY per unit | Ends as soon as the budget limit is reached. As of October 5, 2026, the application amount for renovations is displayed as 8% of the budget on the official site. Please check the official site for the status of applications. |
| Kanagawa Prefecture “Fiscal Year Reiwa 8 Subsidy for Introduction of Self-Consumption Type Renewable Energy” | Corporations and individuals filing blue returns (individual residences are not eligible). Solar power must have a generation output of 10 kW or more, for business facilities, and equipment not certified under FIT/FIP. | Solar Power: 80,000 JPY per kW, etc. Storage System: 50,000 JPY per kWh (up to 5,000,000 JPY) |
Recruitment ended on September 3, 2026 (the application amount reached the budget amount). |
The subsidy for the installation costs of residential solar panels in Fujisawa City has ended for the Reiwa 8 fiscal year. For the city’s subsidy, construction must begin after receiving the grant decision notification, and similarly for Kanagawa Prefecture’s residential subsidies, construction must start after receiving the “grant decision.” If construction begins beforehand, it will not be eligible. The eligibility conditions, application procedures, and whether they can be combined differ by program, and applying does not guarantee that a grant will be awarded, so please confirm before signing a contract or starting construction.
Kakeru Koumuten will provide guidance on eligibility conditions and application periods for each program after confirming them.
National Subsidy “DR Home Battery Project (Support Project for Home Battery Systems for DR Resource Introduction)”
The national government has been implementing the “DR Home Battery Project” to support the installation of home batteries.
This program targets those who are introducing registered battery systems that can be utilized for demand response (DR), and in the Reiwa 7 fiscal year supplementary project, the subsidy amount was determined based on a standard amount of 34,500 yen per 1 kWh of initial effective capacity, with a subsidy rate of up to 30% and a maximum subsidy of 600,000 yen per application. There are conditions such as that contracts or orders made before the grant decision are not eligible.
However, the Reiwa 7 fiscal year supplementary project reached its budget on May 29, 2026, and the application period has ended. The official site also states that there are no plans to reopen applications, and currently, applications cannot be made. Please check the official site for future application opportunities.
Furthermore, there are currently no subsidies specifically for the installation of solar panels on existing homes confirmed by the national government.
👉 Click here for the official site of the DR Home Battery Project
Kanagawa Prefecture “Reiwa 8 Fiscal Year Kanagawa Prefecture Residential Solar Power and Battery Installation Subsidy”
Kanagawa Prefecture provides subsidies for those who install both “solar panels” and “batteries” in their homes.
The subsidy amounts are 70,000 yen per 1 kW of solar power generation output and 150,000 yen per battery system.
For example, if you install a 4 kW solar panel and one battery, the subsidy amount would be calculated as 4 kW × 70,000 yen + 150,000 yen = 430,000 yen.
The eligibility requirements include that the home must ensure seismic performance, the battery system must be a registered product, if construction begins before the grant decision, it will not be eligible, and the application must be made by the individual (applications by contractors on behalf of the homeowner are not allowed). The Fujisawa City subsidy can be combined with national and prefectural subsidies, as stated on the city’s official page, so please confirm the conditions for combination before signing a contract.
In the Reiwa 8 fiscal year, the first application period (May 11 to June 30) and the second application period (starting September 7, first-come-first-served) were held, and the second period has closed as the application amount reached the budget on September 7, 2026. For future recruitment, please check the official page of Kanagawa Prefecture.
👉 Click here for the official page of Kanagawa Prefecture
Kanagawa Prefecture “Reiwa 8 Year Subsidy for Self-Consumption Type Renewable Energy Introduction” (For Businesses)
In Kanagawa Prefecture, there is also a subsidy for businesses that introduce “self-consumption type” facilities that use electricity generated by solar panels.
Eligible applicants are corporations or individual business owners filing blue returns, and individual residential installations are not eligible.
Solar power generation must have an output of 10kW or more, supply electricity to business facilities within the prefecture, and not be equipment certified under FIT or FIP, among other conditions.
The subsidy amount is 80,000 yen per kW for solar power generation and 50,000 yen per kWh for the accompanying storage system (with a maximum of 5 million yen).
As the application amount reached the budget amount for Reiwa 8, the application period was closed on September 3, 2026.
Businesses considering the installation of solar panels on commercial buildings in Fujisawa City should check the official Kanagawa Prefecture page for the next application period.
👉 Click here for details
Fujisawa City “Reiwa 8 Year Subsidy for Installation Costs of Residential Solar Panels, etc.”
Fujisawa City is implementing the “Subsidy for Installation Costs of Residential Solar Panels, etc.” to subsidize part of the installation costs for residential solar power systems and lithium-ion storage batteries.
● Residential solar power system: 15,000 yen per kW of maximum output (maximum 50,000 yen) / 90 applications (first-come, first-served)
● Residential lithium-ion storage battery: 50,000 yen per unit / 150 applications (first-come, first-served)
If there are any delinquent taxes, the application cannot be accepted. Construction must begin after receiving the “Subsidy Grant Decision Notification” issued after application, and the completion report must be submitted by March 23, 2027. The restriction period is 10 years for solar power systems and 6 years for storage batteries. It is possible to combine with national and prefectural subsidies, but separate applications are required, as stated on the city’s official page.
Applications for solar power generation reached the planned number on June 29, 2026, and for storage batteries on July 28, thus closing acceptance (City’s official page, updated September 28, 2026). Currently, applications cannot be made. Please check the city’s official page for future acceptance.
👉 Click here for Fujisawa City’s official page
Solar Panel Installation & Storage Battery Installation Price List
⇧Service Menu | Click here for costs related to Solar Panel Installation and Battery Installation
⇧Service Menu | Click here for costs related to Solar Panel Removal and Water Heater Removal
Breakdown of Installation Capacity, Equipment, and Construction Costs
The costs for solar panels and batteries should be confirmed by separating them into “Equipment Costs (Device Costs)” and “Construction Costs”.
Even for the same “Complete Solar Panel Installation,” the amount can vary significantly depending on the installation capacity, equipment grade, and roof condition.
Considerations for Installation Capacity (kW) and Battery Capacity (kWh)
The installation capacity of solar panels is determined by “Output of One Panel (W) × Number of Panels”, with the unit being kW (kilowatts). Batteries are compared based on the amount of electricity they can store, represented in kWh (kilowatt-hours).
The amount of kW that can be installed on a roof varies for each house based on the 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 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 estimated amounts and may vary based on factors such as wiring length, scaffold range, existing roofing materials, and panel layout.)
▶ Installation Menu | Costs for Solar Panel Installation and Battery Installation
Items to Check on the Quotation (Cost Confirmation)
When comparing prices in competitive quotes, it is common to compare different capacities and equipment. Please check if the following items are clearly stated in each company’s quotation!
| 1. Solar Panels | Manufacturer, model number, output per panel (W), number of panels, total installation capacity (kW). |
| 2. Power Conditioner | Manufacturer, model number, capacity, number of units, installation location (indoor/outdoor). Also check if it is a type that controls in conjunction with the battery. |
| 3. Battery | Manufacturer, model number, capacity (kWh), range usable during a power outage (entire house or specific circuits), installation location. |
| 4. Mounting Frame and Hardware | Name of hardware suitable for roofing materials and method of securing (whether it involves drilling holes or clamping). |
| 5. Wiring and Electrical Work | Wiring route and length, work around the distribution board, presence of a monitor to check power generation. |
| 6. Roof Reinforcement and Waterproofing | Details of waterproofing treatment at fixed points, whether necessary roof repairs and substrate reinforcements are included. |
| 7. Applications | Extent of support for applications to the power company, certification application for selling electricity (FIT), and subsidy applications. |
| 8. Scaffolding | Scope and quantity of scaffolding. If 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 the price is tax-inclusive or tax-exclusive, conditions under which additional costs may arise, and details and duration of manufacturer and workmanship warranties. |
If the capacities differ, the amounts and power generation will also change. Kakeru Koumuten Co., Ltd. welcome competitive quotes, so if you bring quotes from other companies, we will explain the differences for each item!
Self-Quotation and Profit Simulation for Solar Power Generation
With the simulator above,
you can get an estimated quote and income simulation for up to 30 years!
If you know the total installation capacity of solar panels on the roof and the capacity of the storage battery, you can obtain an estimated quote and income simulation!
*The simulation results are estimates. Actual income may vary based on assumptions such as electricity rates, self-consumption ratios, selling prices, and costs for equipment inspection or replacement.
Customer Feedback
-
customer reviews
Asao-ku, Kawasaki City | We received reviews about the ridge cap and rain gutter replacement work!
-
customer reviews
Kohoku-ku, Yokohama | We received reviews about the roof overlay (cover method)!
-
customer reviews
Kohoku-ku, Yokohama | We Received Reviews About Exterior Painting!
-
customer reviews
Hodogaya-ku, Yokohama | We received reviews about our exterior fence construction!
-
customer reviews
Tsurumi-ku, Yokohama | We received reviews about roof and exterior wall painting, as well as metalwork and rain gutter replacement work!
-
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 Manufacturing/Aluminum Catch Type Hardware |
| Fixing Method and Waterproofing Details |
| 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 introduction of solar panels and storage batteries. I have 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 Fujisawa City
There are many solar panel installation contractors available in Fujisawa City, and you may be unsure which one to choose.
For this reason,when requesting the installation of solar panels or storage batteries, let’s confirm the following four points.
● Not only knowledge of solar power but also extensive knowledge of roofing
● Confirm the presence or absence of warranties and aftercare
● 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.
Knowledge of roofing as well as solar panels
Defective installation of solar panels can be caused by a lack of knowledge and confirmation regarding roofing and waterproofing.
While knowledge of solar panels is certainly important, understanding the roofing and waterproofing at the installation site of the solar panels is also crucial.
⚠︎Examples of troubles caused by insufficient checks on roofing and waterproofing
・Solar panels installed on a deteriorated roof causing leaks
・Solar panels installed on a roof with a short lifespan, necessitating a remodel for removal and reinstallation within a few years
・Misjudgment of the type of waterproofing leading to incorrect treatment and subsequent leaks
and more
When installing solar panels, understanding the condition and type of the existing roof allows you to avoid unnecessary expenses and unexpected troubles.
▶ Go to “Roof Check Before Installing Solar Panels” in this article
Confirm the presence or absence of warranties and aftercare
When choosing a solar installation contractor, let’s confirm the presence or absence of warranties. It is important to check not only the duration of the warranty but also the coverage, disclaimers, and cost conditions.
Solar panels and storage batteries come with manufacturer warranties, but also confirm the presence or absence of installation warranties in case leaks occur after installation!
If the contractor offers an installation warranty, they may cover leaks that occur after installation within the warranty period and conditions.
Additionally, some contractors provide aftercare services separate from warranties, so be sure to check if the contractor you are considering has aftercare services.
Since abnormalities or damage on the roof may not be visible, you might not notice them yourself.
By conducting inspections during aftercare, you can easily detect abnormalities early, preventing major repairs or failures!
At Kakeru Koumuten Co., Ltd., the installation of solar panels comes with a leak warranty as part of our workmanship warranty. (The warranty for solar panel installation is 10 years, and depending on the condition of the roof before installation, we may not be able to provide a warranty unless a roof renovation is performed.)
We also provide aftercare maintenance, sending out annual DM notifications!
After reviewing the DM, if you wish, we will visit you for aftercare maintenance!
Obtain estimates from multiple contractors (3 companies as a guideline)
When requesting the installation of solar panels, let’s obtain estimates from multiple contractors.
Even for the same manufacturer and the same construction content, costs and warranties or after-sales services may vary.
Additionally, obtaining multiple estimates makes it easier to negotiate prices.
To request your desired contractor at a lower price, we recommend obtaining estimates from multiple contractors.
When comparing estimates, please check:
“Check the estimate items”
“Types of solar panels”
“Warranties and after-sales services”
and make a detailed comparison! 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” in this article
Check if they provide support for subsidy applications
There may be subsidies available for the installation of solar panels and storage batteries, but if the order of procedures is incorrect or there are deficiencies in the documents, the subsidy may not be granted.
For systems like Kanagawa Prefecture’s housing subsidies, where applications cannot be submitted by the contractor and must be done by the individual, 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 prefectural housing subsidy, this means obtaining a grant decision) before proceeding with the construction!
For the prefectural housing subsidy, after the construction is completed, a performance report must be submitted, and the grant will be provided after review! (The flow of procedures varies by system)
▶ Go to “Subsidies and Grants that May Apply in Fujisawa City” in this article
Benefits of Introducing Solar Equipment
The benefits of installing 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 10 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 attractive!
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 will be set at “24 yen/kWh for the first 4 years, and 8.3 yen/kWh from the 5th to the 10th year.” The same price will apply for the 2026 fiscal year. After the 5th year, it is generally more advantageous to use it at home (self-consumption) rather than selling it, so combining it with a storage battery is also an 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 amount through subsidies is a significant advantage!
In the case of Fujisawa City, there is a possibility of being eligible for the programs from the national government, Kanagawa Prefecture, and Fujisawa City (please check the application status for each program).
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 power generation method (however, devices like power conditioners do have operational noise).
Advantage 4 Heat insulation effects can be expected!!
By installing them on the roof or rooftop, the panels block direct sunlight from hitting the roof.
Especially in summer, it can help reduce the temperature of the roof, providing expected heat insulation effects!
（This does not improve the insulation performance of the building itself）
Benefit 5 Electricity can be used even during power outages!!
If a storage battery is installed, it is possible to use electricity even during emergencies such as power outages!
Even without a storage battery, if you have a power conditioner with autonomous operation capability, you may be able to use electricity from a dedicated outlet during daytime generation.
（The devices, output, and duration that can be used during a power outage vary depending on the model and wiring method）
What points should be noted when introducing solar power generation?
Next, we will explain the “three points to note” when installing solar panels!
Point 1 Maintenance costs can be incurred
A particularly overlooked maintenance cost is for the roof where solar panels are installed.
If you perform roof renovations 10 to 20 years later, there will be costs for removing and reattaching the solar panels.
If the existing roof is deteriorated, it is reassuring to renovate it with durable roofing materials before installing solar panels!
Additionally, there will be costs for regular inspections of the equipment, repairs or replacements of the power conditioner, and updates due to the deterioration of the storage battery.
It would be reassuring to consider maintenance costs in advance and request a 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 fixing brackets to the roofing material or substrate with screws, waterproofing of the fixed parts becomes crucial.
In methods that involve making holes in the roof, the risk of leaks inevitably arises.
Of course, we will ensure proper waterproofing, but if you are concerned about making holes, replacing the roofing material with a metal roof and fixing the solar panels using the catch method is also one option. (The catch method has compatibility conditions between the roofing material and brackets, and it cannot be used with all metal roofs)
Catch-type base metal fittings for horizontal metal roofs
Note 3: The roof will become heavier
Since solar panels will be installed, the roof will become heavier. After investigating the existing roof, substrate, and load capacity, 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!
How to Choose 1: Compare by Total Output of the Roof
When installing solar panels on the roof, it is important to know how much power can be generated in a limited area, and the more power 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 like the higher output panel is better at first glance.
However, if the size of the panels 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,” resulting in different numbers of panels that can be installed on the same roof due to size differences.
400W×15 panels = 6kW (total output of the roof)
350W×20 panels = 7kW (total output of the roof)
As shown above, even if the output of a single panel is lower, the total output of the roof may be higher!
It is important to consider the total output of the roof rather than the output of a single panel!
*The above is a calculation of total output (kW). The actual power generation amount (kWh) will vary depending on conditions such as roof orientation, slope, and shading.
How to Choose 2: Compare by Degradation Rate of Solar Panels
Solar panels have a degradation rate, and their output gradually decreases over 10 and 20 years.
The degree of output reduction after long-term use varies by product. The manufacturer’s output guarantee value is a standard figure for warranty purposes and does not indicate the actual degradation rate or power generation amount.
Choosing solar panels by considering the degradation rate as well as the initial output will help you avoid regrets!
How to Choose 3: Compare by Warranty Period
There are several types of warranties for solar panels, including “output warranty,” “natural disaster warranty,” and “system warranty,” and the warranty periods vary by manufacturer.
For output warranties, some manufacturers offer a 30-year warranty while others provide a 10-year warranty, so it varies widely!
Since longer warranties are generally better, 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 Fujisawa City
We have compiled frequently asked questions from customers considering the installation of solar panels and storage batteries in Fujisawa City. (Tap to open the answers)
How much does it cost to install solar panels and storage batteries in Fujisawa City?
The cost varies depending on the installation capacity, equipment, and roof condition. In the above construction example (solar panel 4.3kW + storage battery, completed in April 2025), it was 2.2 million yen to 2.3 million yen.
Guidelines for different capacities are available on the solar panel 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 Fujisawa City?
As of October 6, 2026, the subsidy for residential solar panel installation in Fujisawa City (up to 15,000 yen per 1kW of maximum output, with a cap of 50,000 yen; 50,000 yen per storage battery) has reached the planned number of applications for the fiscal year 2026 and is no longer accepting applications (solar panels closed on June 29, storage batteries on July 28). The Kanagawa Prefecture subsidy (70,000 yen/kW for solar panels; 150,000 yen per storage battery) reached its budget amount for the second phase of fiscal year 2026 on September 7 and has closed, and the national DR household storage battery project has ended its public recruitment.
Since the application status may change, please refer to the subsidy and grant section and consult with us before signing a contract.
Can I apply for subsidies even after the construction is completed?
Both the Fujisawa City subsidy and the Kanagawa Prefecture subsidy require procedures to be completed before construction. For the city subsidy, construction must begin after receiving the notification of grant decision, and for the prefecture subsidy, “construction must start after the grant decision” is a condition; if construction begins beforehand, it will be ineligible.
The order of procedures varies by program, so please confirm before signing a contract or starting construction.
Can solar panels be installed on a slate roof? I’m worried about leaks.
It is possible to install on a slate roof, but it is necessary to check the condition of the roofing material and substrate beforehand. The fixing method varies by construction method, and when fixing 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 if deterioration is advanced, we can also propose methods such as roof overlay (cover method) or replacement before installation.
The roof is old. Should I do 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, it may be more cost-effective to renovate with durable roofing materials before installation.
Please consult us about the installation process after confirming the condition of the roof through a site survey!
Is it better to install a storage battery together with solar panels?
For those who want to use 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, Kanagawa Prefecture’s subsidy requires the simultaneous introduction of solar panels and storage batteries. In Fujisawa City, there are separate subsidy frameworks for solar power systems and storage batteries (15,000 yen per 1 kW of solar power, with a maximum of 50,000 yen; 50,000 yen per storage battery). You can compare “solar power only” and “solar power + storage battery” through a financial simulation.
How many kW can be installed on my roof? Is it okay for north-facing roofs or those with shadows?
The capacity that can be installed varies depending on the shape, orientation, and size of the roof. At Kakeru Koumuten, we create a layout diagram from the drawings and site survey, and provide you with the installation capacity and power generation simulation.
Fujisawa City has areas close to the sea, residential areas on plateaus, and lowlands along rivers, so the shading from surrounding buildings and trees, as well as the installable capacity, 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 panels 4.3 kW + storage battery), it took about 3 days. The duration may vary if roof work is done simultaneously or depending on the shape of the roof and installation capacity.
Please note that additional time is required for applications for subsidies and power companies, so please consult us as soon as possible.
What is the current selling price (FIT)?
For residential use (under 10 kW), from the certification after October 2025, the first four years will be 24 yen/kWh, and from the fifth to the tenth year, it will be 8.3 yen/kWh, with the same price applied in the 2026 fiscal year.
The idea is to recover initial costs more quickly in the first four years and then focus on self-consumption. Kakeru Koumuten provides a financial simulation that considers loan interest rates and electricity costs.
Can you handle maintenance and inspections after installation?
Yes, we can. Kakeru Koumuten sends out annual after-maintenance notices via DM 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 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. Kakeru Koumuten can remove and reinstall solar panels in-house, allowing us to remove the panels, perform roof overlay (cover method) or re-roofing, and then reinstall them, all in a consistent manner. The removed panels can be stored in our own 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 company in Fujisawa City, please consult Kakeru Koumuten
Our company handles many exterior renovations, including solar panels, roof work, and exterior wall work in Fujisawa City.
We receive requests from many customers, including renovation companies and real estate agencies!
Kakeru Koumuten promises “high-quality renovations at low costs”, and we have received great feedback from numerous customers.
We continue to update our annual construction achievements 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 installations for exterior walls.
We are also happy to handle small jobs like partial repairs and rain gutter cleaning!
In urgent cases like leak repairs, we may be able to provide temporary measures without setting up scaffolding, as long as safety can be ensured, so please consult us!
“I want to know about recommended solar panels“, “I want to keep costs as low as possible“, “I just want an estimate for now“, we will provide the best solutions for your specific requests.
We will never propose unnecessary work that prioritizes profit!
We always stand in our customers’ shoes and will propose the best construction plans!
We are confident that we will not be outdone in terms of cost, quality, and efficiency compared to other companies in exterior construction!
We welcome competitive quotes because we are confident!
Estimates are completely free, and if you find our company to be inferior to others, feel free to decline!
Characteristics of Fujisawa City and Points for Solar Work
Fujisawa City is located in the central southern part of Kanagawa Prefecture, with the southern part facing Sagami Bay (Pacific Ocean), and the area of the city is approximately 69.56 square kilometers, with a coastline extending about 5.2 kilometers. The northern plateau and hills, southern coastal area, and lowlands along the rivers flowing through the city have different surrounding environments. We have summarized the characteristics of Fujisawa City’s topography and climate, as well as points to consider when installing solar panels and storage batteries below. (Tap to open)
View the characteristics of Fujisawa City and points for solar work
■ For coastal areas facing Sagami Bay, confirm installation location and equipment specifications in advance
The southern part of Fujisawa City is composed of Enoshima and the Shonan sand dune area along the coast. When installing in locations close to the sea, it is important to confirm in advance whether the panels, power conditioners, and storage batteries meet the manufacturer’s installation conditions (such as whether they are in a salt damage-prone area). If you want to use electricity during a power outage, please consider installing a storage battery.
■ In residential areas on plateaus and hills, be cautious of shadows and fallen leaves from surrounding buildings and trees
The northern part of the city is described as being composed of the Sagami Plateau and the Takakusa Hills at an elevation of 40 to 50 meters, as well as lowlands created by rivers. In densely populated areas or sites close to trees and green spaces, it is necessary to be cautious of shadows cast by neighboring houses and trees, as well as the reduction in power generation due to fallen leaves and dirt. Kakeru Koumuten Co., Ltd. can also handle solar panel cleaning with specialized brushes and rain gutter cleaning.
■ In lowlands along rivers, also check the placement of storage batteries and equipment
The city has rivers such as Hiki River, Sakaigawa, Kashio River, Mekujiri River, and Koide River, which create extensive lowlands. In sites close to rivers, it is important to plan by checking the surrounding environment of the installation locations for storage batteries, distribution boards, power conditioners, etc. (such as whether it is a place where water tends to accumulate). Please check the information about your area on hazard maps and consult us about the installation location.
■ Because conditions differ along the sea, plateaus, and rivers, we check roofs and sites individually through on-site surveys
In Fujisawa City, where the conditions differ between sites close to the sea, residential areas on plateaus, and sites along rivers, the types of roofs, years built, and sunlight exposure vary from house to house. At Kakeru Koumuten Co., Ltd., we will confirm the type and condition of the roof and the situation of the site before installation and propose methods for securing, waterproofing, and scaffolding plans.
■ Annual sunlight hours are approximately 1,897 hours, and annual precipitation is approximately 1,539mm
According to materials from Fujisawa City, the city’s average annual sunlight hours are 1,897 hours, and the average annual precipitation is 1,539mm, which is about the same as other cities nationwide in terms of sunlight hours, but slightly more in terms of precipitation.
Power generation varies by season and location, so conducting annual power generation simulations and selecting the capacity of storage batteries to match the times when electricity is used most is key.
Our company is based in Kanagawa Prefecture and handles many exterior construction and solar work projects in Fujisawa City.
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 sudden troubles!
Service Area in Fujisawa City
Kakeru Koumuten Co., Ltd. accepts requests throughout Kanagawa Prefecture and Tokyo.
List of Areas in Fujisawa City
Asahi-cho, Fujisawa City / Ishikawa, Fujisawa City / Inari, Fujisawa City / Imada, Fujisawa City / Uchimodori, Fujisawa City / Enoshima, Fujisawa City / Engyo, Fujisawa City / Oba, Fujisawa City / Dakkyo, Fujisawa City / Katase, Fujisawa City / Katase Kaigan, Fujisawa City / Katase Mejirozan, Fujisawa City / Kataseyama, Fujisawa City / Kameino, Fujisawa City / Karasawa, Fujisawa City / Kawana, Fujisawa City / Kirihara-cho, Fujisawa City / Kugenuma, Fujisawa City / Kugenuma Ishigami, Fujisawa City / Kugenuma Kaigan, Fujisawa City / Kugenuma Sakuragaoka, Fujisawa City / Kugenuma Shinmei, Fujisawa City / Kugenuma Tachibana, Fujisawa City / Kugenuma Hanazawa-cho, Fujisawa City / Kugenuma Fujigatani, Fujisawa City / Kugenuma Matsugaoka, Fujisawa City / Kugenuma Higashi, Fujisawa City / Kuzuhara, Fujisawa City / Kozuka, Fujisawa City / Shimododana, Fujisawa City / Jonan, Fujisawa City / Shonandai, Fujisawa City / Ayamezawa, Fujisawa City / Shirahata, Fujisawa City / Zengyo, Fujisawa City / Zengyo Saka, Fujisawa City / Zengyo Danchi, Fujisawa City / Oogiri, Fujisawa City / Takakura, Fujisawa City / Takaya, Fujisawa City / Tateishi, Fujisawa City / Nagato, Fujisawa City / Tsujido, Fujisawa City / Tsujido Shindai, Fujisawa City / Tsujido Shinmachi, Fujisawa City / Tsujido Taihei-dai, Fujisawa City / Tsujido Tokai Coast, Fujisawa City / Tsujido Nishi Kaigan, Fujisawa City / Tsujido Motomachi, Fujisawa City / Dodana, Fujisawa City / Tenjin-cho, Fujisawa City / Namikidai, Fujisawa City / Nishitomi, Fujisawa City / Nishimatano, Fujisawa City / Hatori, Fujisawa City / Hananoki, Fujisawa City / Fujigaoka, Fujisawa City / Fujisawa, Fujisawa City / Hon Kugenuma, Fujisawa City / Honmachi, Fujisawa City / Hon Fujisawa, Fujisawa City / Misono-dai, Fujisawa City / Minami Fujisawa, Fujisawa City / Miyahara, Fujisawa City / Miyamae, Fujisawa City / Mirokuji, Fujisawa City / Muraoka Higashi, Fujisawa City / Yodani, Fujisawa City / Watanai, Fujisawa City
・Please leave the exterior wall painting in Fujisawa City to Kakeru Koumuten!
・Please leave the roof renovation in Fujisawa City to Kakeru Koumuten!
・Please leave the exterior renovation in Fujisawa City to Kakeru Koumuten!
・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 comparison estimates and key points!
・12 major manufacturers of solar power generation! Features and selection points also introduced!
・What are the installation costs for solar power generation? Thorough explanation of tips to reduce costs!
・What are the best places for solar power installation? Key points for selecting installation locations also introduced!
・Here is the introduction to solar power generation estimates!
Consultations via LINE are also very welcome◎
We are also updating our Instagram regularly◎Please follow us, thank you◎
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!
