Leave Your Solar Panel Installation Work in Yamato City, Kanagawa Prefecture to Kakeru Koumuten Co., Ltd.!
For Solar Panel and Battery Installation in
Yamato 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 Yamato City”
“Costs for Solar Panel and Battery Installation”
“Subsidies Available for Solar System Installation in Yamato City”
We will also explain the above three points!
Installing solar panels carries risks such as“the occurrence of leaks” and other troubles.
To ensure you have no regrets about your solar panel installation, we recommend obtainingestimates from about three companies!
Table of Contents (Tap to Open/Close)
- Reasons Kakeru Koumuten is Chosen for Solar Panel Installation in Yamato City
- Roof Inspection Before Installing Solar Panels
- Subsidies and Grants Available in Yamato City
- Price List for Solar Panel and Storage Battery Installation
- Breakdown of Installation Capacity, Equipment, and Construction Costs
- Self-Estimate and Profit Simulation for Solar Power Generation
- Customer Testimonials
- Case Studies of Solar Panel Installations
- How to Choose a Solar Panel Installer in Yamato 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 Yamato City
- If You Are Looking for a Solar Panel Installer in Yamato City, Contact Kakeru Koumuten
- Characteristics of Yamato City and Key Points for Solar Installation
- Service Area in Yamato City
Reasons Kakeru Koumuten is Chosen for Solar Panel Installation in Yamato City
Regarding why we are entrusted with solar panel installation by customers in Yamato City,
“Our 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 Also Handle Exterior Renovations Beyond Solar Panel Installation!
Problems such as leaks that occur with solar panel installations 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 Co., Ltd. is strong in roofing work and can also detach and attach solar panels in-house, allowing for quick responses to maintenance and urgent troubles after solar panel installation!
2.Facilities Specialized in Exterior Renovation
Kakeru Koumuten Co., Ltd. has organized the following warehouses and material storage areas to provide low-cost, high-quality solar work and exterior renovations.
We have established five bases centered around Yokohama City, Kanagawa Prefecture for material storage and showrooms.
In-house Ownership of Scaffolding Materials
To ensure safety during work on the roof, we own the scaffolding materials necessary for temporary scaffolding depending on the construction conditions and can assemble scaffolding in-house.
By not outsourcing scaffolding work and using our own scaffolding team, we can also cut costs on scaffolding work.
We own scaffolding materials for approximately 50 single-family homes!
Even in cases where 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 paint, wood, and metal.
By sorting and recycling waste materials, we can significantly cut waste disposal costs.
Exterior Renovation Dedicated Showroom
In the showroom, not only can you have meetings, but you can also
check the actual foundation brackets for solar panels and see how they are installed on roofing materials!
We can also provide simulations for potential earnings and installation costs when introducing solar panels!
Since roofing and exterior wall work often accompany these projects, we also have samples of roofing materials and models that explain the structure, allowing us to provide 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 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 construction industry permits as well as permits for industrial waste collection and transportation!
We also have nationally certified sheet metal and painting technicians, and we are confident in our construction skills.
We can also handle large-scale roof projects such as factories!
5. Warranty and Aftercare
In addition to the manufacturer’s warranty, solar panel installation work comes with our own construction warranty (leak 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 without performing a roof renovation. The construction warranty is separate from the manufacturer’s product warranty, and the scope and conditions vary based on the warranty details.)
Aftercare is available annually, and we send out notification DM every 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 at high altitudes, we can utilize drones to assist!
During leak investigations, we can also conduct inspections using a thermal imaging camera.
If the power generation of solar panels decreases due to dirt, we can provide cleaning with a specialized brush.
We will respond according to the customer’s wishes.
7. Human Resource Development
To improve skills, we create various roof models and conduct practical training.
Since the construction methods vary depending on the shape and slope of the roof, we regularly provide technical training so that each staff member can handle various cases.
8. Creation of Easy-to-Understand Materials and Simulations
Kakeru Koumuten provides not only “estimates,” “layout diagrams,” and “power generation simulations” but also a “solar construction guidebook” and a “profit and loss simulation” that takes into account loan interest rates and electricity costs.
The profit and loss simulation can be created for projected cumulative profits and losses over 20 to 30 years.
Even customers who are not familiar with solar construction will receive materials that clearly summarize points to consider, including cautions 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 safe 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 affects 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 it with a power generation simulation. |
| 4. Roof Shape and Usable Area | The number of panels that can be installed (installation capacity) is determined by the shape and size of the roof. The number of panels that can be installed varies depending on the size of the panels, so we will compare based on the total output of the roof. |
| 5. Fixing Method and Waterproofing Details | We will check whether the method involves drilling holes in the roofing material for fastening or using brackets to secure the roofing material. The fixing method varies by construction method, so please confirm the waterproof treatment of the fastening parts during the estimate. |
| 6. Weight of the Roof | The roof will become heavier due to the panels being installed. 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 also affects the cost. |
| 8. Ease of Scaffolding Setup and Delivery Route | If there are elevation differences on the site, planning for scaffolding and the delivery route for equipment and materials may require some ingenuity. The width of the front road and any steps on the site will also be checked during the 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 with screws to the roof material and substrate) | 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 suited to the type of tile (even methods that do not drill holes in the tiles will fix to the substrate) | Type and condition of tiles, substrate, load-bearing capacity. Depending on the investigation results, there may be methods to replace with lighter 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 plan to renovate the roof 10 to 20 years after installation, additional costs for solar panel removal will apply. If the roof is deteriorating, renovating to a highly durable roofing material before installation may help reduce costs in the long run.
Kakeru Koumuten Co., Ltd. specializes in roofing work and can also handle solar panel removal in-house, so please consult us according to the condition of your roof!
▶ Click here for roof renovations in Yamato City
Potential Subsidies and Grants in Yamato City, Kanagawa Prefecture
If you are introducing solar panels or storage batteries in Yamato City, there is a possibility that “National,” “Kanagawa Prefecture,” and “Yamato City” programs may apply.
The following information is based on the official pages of each program as of October 6, 2026. The application status may change depending on the budget, so please check the latest information before contracting or starting work.
Eligibility Conditions and Application Timing for Subsidy Programs
| Program | Main Eligibility Conditions | Subsidy Amount | Application Period & Status |
|---|---|---|---|
| Yamato City “Regional Decarbonization Transition & Renewable Energy Promotion Key Measures Acceleration Project Subsidy” (for self-consumption type without FIT/FIP certification) | Residents of homes in Yamato City. Must self-consume 30% or more of generated electricity without obtaining FIT/FIP certification. Battery storage must be installed simultaneously with solar power. Apply at least two weeks before the scheduled start date and commence work after the grant decision (work started before the grant decision is not eligible). Cannot be combined with other national subsidies, but can be combined with Kanagawa Prefecture subsidies. | Solar: 70,000 JPY per kW (or the lesser of installation costs) Battery (5-20 kWh): “1/3 of capacity kWh × 155,000 JPY” or 1/3 of installation costs, whichever is less. |
April 10, 2026 – January 29, 2027 (first-come, first-served) According to the city’s official page (updated August 19, 2026), the program may end during the period if the budget is reached, and they do not respond to inquiries about the number of applications submitted. |
| Yamato City “Subsidy for Installation Costs of Residential Solar Power Generation Systems” (when selling electricity with FIT certification) | Must have a maximum output of solar modules or rated output of power conditioners under 10 kW and obtain FIT certification by the performance report. Battery storage must be installed simultaneously with solar power (ZEH registered products). Pre-application must be submitted two weeks before starting work, and performance report must be submitted within 30 days after completion. Can be combined with prefectural and national subsidies. | Solar: 10,000 JPY per kW (up to 40,000 JPY) Battery: Up to 30,000 JPY. |
April 1, 2026 – February 15, 2027 (first-come, first-served) According to the city’s official page (updated October 2, 2026), the program may end during the application period if the budget is reached, and as of October 1, 36 applications have been submitted. |
| Kanagawa Prefecture “Fiscal Year 2026 Kanagawa Prefecture Residential Solar Power Generation & Battery Installation Subsidy” | Must install both solar power generation and battery systems in homes within the prefecture (homes with seismic performance secured). Applications must be submitted by the individual, and work must commence after the grant decision. | Solar: 70,000 JPY per kW Battery: 150,000 JPY per unit. |
Phase 1: May 11, 2026 – June 30, 2026 Phase 2: Starts September 7, 2026 (first-come, first-served) As of September 7, 2026, the application amount reached the budget limit, and applications are now closed. Please check the prefecture’s official page for future applications. |
| National “DR Home Battery Project” (Fiscal Year 2025 Supplement) | Newly install home battery systems that can be utilized for DR (demand response) with registered products. | Calculated based on an initial effective capacity of 34,500 JPY per kWh (subsidy rate within 3/10; maximum 600,000 JPY per application). | As of May 29, 2026, the budget has been reached, and the public offering has ended (the official site states there are no plans to reopen applications, and currently, applications cannot be submitted). |
| National “Mirai Eco Housing 2026 Project” (Renovation) | The storage battery is one of the eligible facilities, but it must be combined with essential construction work such as insulation renovation of windows (openings) and the building structure; installation of the storage battery alone cannot be applied for. Solar panels are not included as eligible facilities. | Storage Battery: 96,000 JPY/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 website. Please check the application status on the official website. |
| Kanagawa Prefecture “Reiwa 8 Year Kanagawa Prefecture Self-Consumption Type Renewable Energy Introduction Subsidy” | Corporations and individual business owners filing blue returns (individual residences are not eligible). Solar power must have a generation capacity of 10 kW or more, facilities for business use, and equipment not certified under FIT/FIP, etc. | Solar Power: 80,000 JPY/kW, etc. Storage System: 50,000 JPY/kWh (maximum 5 million JPY) |
Application closed on September 3, 2026 (when application amounts reached the budget amount). |
For both subsidy systems in Yamato City, a preliminary application is required to be submitted at least two weeks before the scheduled start date, and the subsidy for the priority measures acceleration project excludes construction that begins before the grant decision. The Kanagawa Prefecture housing subsidy also requires construction to start after receiving the “grant decision,” and starting work beforehand will disqualify you. Additionally, the two city systems are on a first-come, first-served basis, and may end during the period once the budget is reached. Eligibility conditions, application procedures, and the possibility of combining systems differ for each program, and applying does not guarantee a grant, so please confirm before contracting or starting work.
Kakeru Koumuten will provide guidance on the eligibility conditions and application periods for each system after confirming them.
National Subsidy “DR Home Storage Battery Project (Support Project for the Introduction of Home Storage Systems for DR Resources)”
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 products of storage systems that can be utilized for demand response (DR), and in the fiscal year 2026 supplementary project, the subsidy amount was determined based on a standard amount of 34,500 JPY per initial effective capacity of 1 kWh, with a subsidy rate of up to 30% and a maximum of 600,000 JPY per application. There are also conditions such as that contracts or orders made before the grant decision are not eligible.
However, the fiscal year 2026 supplementary application amount reached the budget on May 29, 2026, and the public recruitment has ended. The official website also states that there are no plans to reopen public recruitment, and applications are currently not possible. Please check the official website for future public recruitment.
Furthermore, there are currently no subsidies confirmed for the installation of solar panels on existing homes.
👉 Click here for the official website of the DR Home Storage Battery Project
Kanagawa Prefecture “Reiwa 8 Year Kanagawa Prefecture Residential Solar Power Generation and Storage Battery Introduction Subsidy”
Kanagawa Prefecture provides subsidies for those who introduce both “solar panels” and “storage batteries” to their homes.
The details of the subsidy are as follows: 70,000 yen per 1 kW of solar power generation output, and 150,000 yen per storage system.
For example, if you introduce a 4 kW solar panel and one storage battery, the calculation for the subsidy amount would be 4 kW × 70,000 yen + 150,000 yen = 430,000 yen.
The eligible properties are those that ensure seismic performance, and the storage system must be a registered product. Additionally, if construction begins before the grant decision, it will not be eligible, and the application must be made by the individual (applications by the construction contractor on behalf of the individual are not allowed). The subsidies in Yamato City can be combined with both systems of Kanagawa Prefecture, as stated on the city’s official page. Please check the official pages of each system before signing a contract.
For the fiscal year 2026, the first period (May 11 – June 30) and the second period (starting September 7, first-come-first-served) were accepted. The second period has closed on September 7, 2026, as the application amount reached the budget amount. For future recruitment, please check the official page of Kanagawa Prefecture.
👉 Here is the official page of Kanagawa Prefecture
Kanagawa Prefecture “Fiscal Year 2026 Kanagawa Prefecture Subsidy for Introducing Self-Consumption Type Renewable Energy” (for businesses)
Kanagawa Prefecture is also implementing 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 who file blue returns, and the introduction to individual residences is not eligible.
The solar power generation must have an output of 10 kW or more, supply electricity to business facilities within the prefecture, and not be a facility that has received FIT or FIP certification.
The subsidy amount is 80,000 yen per kW for solar power generation, and 50,000 yen per kWh (with a maximum of 5 million yen) for the accompanying storage system.
For fiscal year 2026, applications have closed on September 3, 2026, as the application amount reached the budget amount.
Businesses considering the installation of solar panels on commercial buildings in Yamato City should check the official page of Kanagawa Prefecture for the next recruitment.
👉 For more details, click here
Yamato City “Regional Decarbonization Transition and Renewable Energy Promotion Key Measures Acceleration Project Subsidy (Fiscal Year 2026)”
This is a subsidy for residential solar power generation equipment and storage batteries that do not obtain FIT or FIP certification for those who use the generated electricity at home (self-consumption).
● Solar power generation equipment: 70,000 yen per kW (or the lesser of the installation cost)
● Storage battery (5-20 kWh): “Capacity kWh × 155,000 yen divided by 3” or one-third of the installation cost, whichever is less
The target is residents of homes in Yamato City, and the condition is that more than 30% of the generated electricity must be self-consumed. Storage batteries are eligible when installed simultaneously with solar power generation equipment. You must apply at least two weeks before the scheduled start date and commence work after the grant decision; if work begins before the grant decision, it will not be eligible for assistance. The application period is from April 10, 2026, to January 29, 2027.
Applications are accepted on a first-come, first-served basis, and may end during the period if the budget is reached. The city’s official page (updated August 19, 2026) states that inquiries regarding the number of applications already submitted will not be answered. It is noted that this grant cannot be combined with other national subsidies, but it can be combined with Kanagawa Prefecture subsidies.
👉 Click here for the official Yamato City page
Yamato City “Subsidy for Installation Costs of Residential Solar Power Generation Systems (Reiwa 8)”
This is a subsidy for those who sell electricity (feed-in tariff) after receiving FIT certification.
● Solar Power Generation System: 10,000 yen per kW (maximum 40,000 yen)
● Lithium-ion Storage Battery: Maximum 30,000 yen (only for simultaneous application with solar power)
For solar power, the maximum output of the solar cell module or the rated output of the power conditioner must be less than 10 kW, and FIT certification must be obtained by the time of performance reporting. Storage batteries are only eligible when installed simultaneously with solar power generation systems, and they must be registered ZEH products. Pre-application must be made two weeks before the start of construction, and performance reporting must be completed within 30 days after the construction is finished. The application period is from April 1, 2026, to February 15, 2027.
Applications are accepted on a first-come, first-served basis, and may end during the recruitment period if the budget is reached. The city’s official page (updated October 2, 2026) states that as of October 1, there have been 36 applications submitted. It is noted that it is possible to combine with prefectural and national subsidies.
👉 Click here for the official Yamato City page
Solar Panel Installation & Storage Battery Installation Price List
⇧Service Menu | For Costs Related to Solar Panel Removal and Water Heater Dismantling, Click Here
Breakdown of Installation Capacity, Equipment, and Construction Costs
The costs for solar panels and storage batteries should be 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.
Understanding 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 based on the amount of electricity they can store, measured in kWh (kilowatt-hour).
The amount of kW that can be installed on a roof varies for each house based on the shape, orientation, and size of the roof. At Kakeru Koumuten, we create layout diagrams from blueprints and on-site surveys to present the installation capacity.
On our pricing page, we list solar panels as approximately 800,000 JPY to 1,200,000 JPY for 3-5 kW, and 1,200,000 JPY to 1,900,000 JPY for 6-10 kW. (These are just rough estimates, and the actual cost may vary based on wiring length, scaffolding range, existing roofing materials, panel layout, etc.)
▶ Service Menu | For Costs Related to Solar Panel Installation and Storage Battery Installation, Click Here
Items to Confirm in the Estimate (Cost Verification)
When comparing estimates, it is common to compare items with different capacities and equipment just by looking at the amounts. Please check if the following items are clearly stated in the estimates from each company!
| 1. Solar Panels | Manufacturer, model number, output per panel (W), number of panels, total installation capacity (kW) should be specified. |
| 2. Power Conditioner | Manufacturer, model number, capacity, number of units, installation location (indoor/outdoor). Also check if it is a type that controls the battery together. |
| 3. Storage 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 the hardware suitable for the roofing material and the fixing method (whether it is a method that drills holes or a method that clamps for fixation). |
| 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 fixing points, whether necessary roof repairs and substrate reinforcements are included. |
| 7. Application | How much support is included for applications to the power company, feed-in tariff (FIT) certification applications, and subsidy applications. |
| 8. Scaffolding | Scope and quantity of scaffolding. If roofing work and exterior painting are done simultaneously, check that the same scope and quantity are not counted twice. |
| 9. Removal and Disposal | Whether the removal of existing solar water heaters and old panels, as well as disposal costs for waste materials, are included. |
| 10. Tax Classification and Warranty | Whether prices are tax-inclusive or tax-exclusive, conditions under which additional costs may arise, and details and duration of manufacturer and workmanship warranties. |
If the capacity is different, both the amount and power generation will change. Kakeru Koumuten Co., Ltd. welcome comparisons, so if you bring estimates from other companies, we will explain the differences item by item!
Self-Estimate and Profit and Loss Simulator for Solar Power Generation
With the simulator above,
you can obtain an estimated quote and a profit and loss 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 profit and loss simulation!
*The simulation results are estimates. Actual profit and loss may vary based on assumptions such as electricity rates, self-consumption ratios, feed-in 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 Installations
| Construction Details |
| Solar Panel Installation Battery Installation |
| Existing Roofing Material |
| Horizontal Metal Roof (Super Galtect) |
| Installation Capacity |
| Solar Panel: 4.3kW Battery: 5kWh |
| Base Mounting Hardware Used |
| Niigata Manufacturing/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, 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 heard that grants are available, and I would like to know how much can be granted. |
Our Proposal
We visited to provide an estimate and created a layout diagram for the solar panels from the drawings!
The layout diagram shows the arrangement of solar panels 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 grants, so we explained it to the customer along with the estimate!
How to Choose a Solar Panel Installation Contractor in Yamato City
There are many solar panel installation contractors available in Yamato City, and you may be unsure which one to choose.
For this reason, when requesting solar panel installation and battery installation work, let’s confirm the following four points.
● Not only knowledge of solar power but also extensive knowledge of roofs
● Confirm the presence 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.
Knowledge of roofs as well as solar panels
Defective installation of solar panels can be caused by a lack of knowledge and confirmation regarding roofs and waterproofing.
While knowledge of solar panels is certainly important, understanding the roof and waterproofing at the installation site of the solar panels is also crucial.
⚠︎Examples of troubles due to insufficient confirmation of roofs and waterproofing
・Solar panels installed on a deteriorated roof causing leaks
・Solar panels installed on a roof with a short lifespan, requiring remodeling for removal and reinstallation within a few years
・Incorrect treatment due to misjudgment of the type of waterproofing, resulting in 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 Confirmation Before Installing Solar Panels” in this article
Confirm the presence of warranties and aftercare services
When choosing a solar installation contractor, let’s confirm the presence of warranties. It is important to check not only the duration of the warranty but also the scope of coverage, disclaimers, and cost conditions.
While the solar panels and battery itself come with a manufacturer’s warranty, also confirm whether there is a workmanship warranty in case of leaks occurring after installation!
For contractors that offer a workmanship warranty, if leaks occur after installation, they may cover it under warranty, provided it is within the warranty period and conditions.
Additionally, some contractors offer aftercare services separate from warranties, so be sure to check if the contractor you are considering has aftercare services.
Since abnormalities or damages on the roof can be in hidden areas, you may not notice them yourself.
By conducting inspections of hidden areas during aftercare maintenance, you can more easily detect abnormalities early and prevent 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 without performing roof renovations.)
We also conduct aftercare maintenance and send out annual DM!
Please check the DM, and 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 may vary, and warranties and after-sales services may differ.
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 carefully:
“Check the estimate items”
“Types of solar panels”
“Warranties and after-sales services”
and make your judgment! If the rank of auxiliary materials is low or if steps are skipped, costs can be reduced, so avoid judging solely based on price!
▶ Go to “Breakdown of installation capacity, equipment, and construction costs” in this article
Check if they provide support for subsidy applications
Subsidies may be available for the installation of solar panels and storage batteries, but if the order of procedures is incorrect or if there are deficiencies in the documents, the grant may not be awarded.
For systems like Kanagawa Prefecture’s housing subsidies, where the contractor cannot apply on your behalf, 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 grant approval) before proceeding with construction!
For the prefectural housing subsidy, after the construction is completed, a performance report will be submitted, and the grant will be awarded after a review! (The flow of procedures varies by system)
▶ Go to “Subsidies and grants that may apply in Yamato City” in this article
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 generated electricity, you can reduce the amount of electricity purchased from the utility company and gain benefits!
As electricity costs rise, the ability to cover your 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 is set at “24 JPY/kWh for the first four years, and 8.3 JPY/kWh from the fifth to the tenth year.” The same price will apply for the fiscal year 2026. After the fifth year, it is generally 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 Subsidies can be utilized!
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 Yamato City, you may be eligible for programs from the national government, Kanagawa Prefecture, and Yamato City (please check the application status for each program).
Advantage 3 Environmentally friendly!
Solar power generation emits low levels of carbon dioxide and reduces dependence on fossil fuels, contributing to the mitigation of global warming.
Solar panels themselves do not produce noise or exhaust gases during the generation process, making them an environmentally friendly method of power generation. (However, devices like power conditioners do have operational noise.)
Advantage 4 Heat insulation effects are expected!!
By installing on the roof or rooftop, the panels block direct sunlight to the roof.
Especially in summer, it can help reduce the temperature rise 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 capabilities, you may be able to use electricity from a dedicated outlet during daytime generation.
（The devices, output, and time available for use during power outages vary depending on the model and wiring method）
What points should be noted when introducing solar power generation?
Next, we will explain the “three points to note” when installing solar panels!
Point 1 Maintenance costs can be incurred
A particularly overlooked maintenance cost is for the roof where solar panels are installed.
If you perform roof renovations 10 to 20 years later, there will be costs for removing and reinstalling the solar panels.
If the existing roof is deteriorated, it is reassuring to renovate it with durable roofing materials before installing solar panels!
Additionally, regular inspections of the equipment, repairs or replacements of the power conditioner, and costs for updating due to the deterioration of the storage battery will also be incurred.
It would be reassuring to ask for a simulation considering maintenance costs before introducing solar panels!
Point 2 The risk of leaks increases depending on the roofing material
The fixing methods for slate roofs and tile roofs vary by construction method, but in methods that fix hardware with screws to the roofing material or substrate, waterproofing of the fixed parts is 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 an option. (The catch method has compatibility conditions between the roofing material and hardware, and it cannot be used with all metal roofs)
Catch-type base metal fittings for horizontal metal roofs
Note 3: The roof will become heavier
Installing solar panels will make the roof heavier. After investigating the existing roof, substrate, and load capacity, one option may be to replace it with a lighter roof 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 roof output
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 at first glance that the higher output panel is better.
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 on the same roof may differ 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 a calculation of total output (kW). The actual power generation amount (kWh) will vary depending on conditions such as roof orientation, slope, and shading.
Choosing Method 2: Compare based on degradation rate of solar panels
Solar panels have a degradation rate, and their output gradually decreases over 10 or 20 years.
The degree of output reduction after long-term use varies by product. The manufacturer’s output guarantee value is a standard figure for warranty purposes and does not indicate the actual degradation rate or power generation amount.
Choosing solar panels without considering the degradation rate can lead to regrets later!
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!
Since a longer warranty is 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 Yamato City
We have compiled common questions from customers considering the installation of solar panels and storage batteries in Yamato City. (Tap to open the answers)
How much does it cost to install solar panels and storage batteries in Yamato 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 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 Yamato City?
As of October 6, 2026, there are two subsidy programs in Yamato City. The “Regional Decarbonization Transition and Renewable Energy Promotion Priority Measures Acceleration Project Subsidy” for self-consumption types that do not obtain FIT/FIP certification offers 70,000 yen per kW for solar power, while the “Subsidy for Installation Costs of Residential Solar Power Generation Systems” for those who receive FIT certification offers 10,000 yen per kW (with a maximum of 40,000 yen). Both are accepted on a first-come, first-served basis as stated on the city’s official page, and may end during the period if the budget is reached. The Kanagawa Prefecture subsidy (70,000 yen/kW for solar power and 150,000 yen/unit for storage batteries) reached its budget on September 7 for the second phase of Reiwa 8 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 before signing a contract.
Can I apply for subsidies even after the construction is completed?
No, you cannot. Both subsidy programs in Yamato City require prior application at least two weeks before construction starts, and the acceleration project subsidy requires construction to start after the grant decision. The Kanagawa Prefecture residential subsidy also requires “construction to start after the grant decision,” and starting construction beforehand will make you 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 first. The fixing method varies by construction method, and if the method involves fixing brackets to the roofing material or 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 and suggest methods such as roof overlay (cover method) or replacement if deterioration is progressing.
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 after 10 to 20 years of 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 with durable roofing materials before installation.
Please consult us on how to proceed with the installation after checking the condition of the roof through a site survey!
Should I install a storage battery together with the solar panels?
If you want to use the generated electricity at night or prepare for power outages, simultaneous installation is recommended. The selling price 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 subsidies in Kanagawa Prefecture require the simultaneous installation of solar panels and storage batteries, and the subsidies in Yamato City also apply only when the storage battery is installed at the same time as the solar power generation system. You can compare “solar only” and “solar + storage battery” through a financial simulation.
How many kW can be installed on my roof? Is it okay for north-facing roofs or roofs with shadows?
The capacity that can be installed varies depending on the shape, orientation, and size of the roof. Kakeru Koumuten Co., Ltd. will create a layout diagram from the drawings and site survey, and provide you with the installation capacity and power generation simulation.
Yamato City has very little hilly terrain, but the shading from surrounding buildings and trees, as well as the installable capacity, varies from house to 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 (4.3 kW solar panels + 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 as soon as possible.
What is the current selling price (FIT) for electricity?
For residential use (less than 10 kW), the selling price from certifications after October 2025 will be 24 yen/kWh for the first 4 years, and 8.3 yen/kWh from the fifth to the tenth year, and the same price will apply for the 2026 fiscal year.
The idea is to recover the initial costs quickly in the first four years and focus on self-consumption afterward. Kakeru Koumuten Co., Ltd. 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 Co., Ltd. sends out annual after-maintenance notices via DM and visits customers who request 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 handle renovations for 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 they are reinstalled. 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 Yamato City, please consult Kakeru Koumuten
Our company handles many exterior renovations, including solar panel installations, roof work, and exterior wall work in Yamato City.
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 achievements and will strive to improve quality to satisfy even more customers in the future.
Our company can perform not only roof overlay (cover method) and re-roofing but also partial roof repairs, exterior wall painting, and exterior wall cover methods entirely in-house.
We are also happy to handle small jobs like partial repairs and rain gutter cleaning!
In urgent cases such as leak repairs, we may be able to provide emergency measures without setting up scaffolding, as long as safety can be ensured, so please consult 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 will propose the best construction plan!
We are confident that we will not be outdone 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 Yamato City and Points of Solar Work
Yamato City is located almost in the center of Kanagawa Prefecture, within a 40 km radius from the city center, and is a long, narrow city with an area of 27.09 square kilometers. It is situated on a plateau collectively referred to as the Sagaminodai Plateau, and is described as having little to no hilly terrain. We have summarized the characteristics of Yamato City’s terrain and points to consider when installing solar panels and storage batteries below. (Tap to open)
View the characteristics of Yamato City and points for solar construction
■ Even in a city with little hilly terrain, confirm the site and delivery route on-site
Yamato City is said to have a long and narrow area with little hilly terrain, with the highest elevation in the city being about 91m and the lowest about 28m. Even in a city with little elevation change, the planning of scaffolding and the delivery routes for equipment and materials such as panels and storage batteries will vary depending on the height differences of each site and the width of the front road. Kakeru Koumuten Co., Ltd. plans scaffolding to match the site even when there are height differences using our own scaffolding team and materials.
■ Near rivers flowing through valleys between plateaus, check the equipment placement using hazard maps
It is noted that there are narrow valleys between the Sagaminodai Plateau, with the Sakai River flowing on the eastern side of the city and the Hikichi River flowing on the western side. The placement of equipment such as storage batteries and power conditioners will change depending on the surrounding environment of the installation site (whether it is prone to water accumulation, etc.). Please check the information about your area using hazard maps and consult us about the installation location.
■ Shadows and dirt from surrounding buildings and trees should be checked for each house
The amount of power generation can also vary due to the shadows cast by surrounding buildings and trees, as well as the accumulation of fallen leaves and dirt. Before installation, we will check the orientation and slope of the roof and the surrounding conditions on-site. If the power generation decreases after installation, we can also handle cleaning the solar panels with a dedicated brush and cleaning the rain gutters.
■ The types of roofs and their ages vary from house to house. Check the roof and waterproofing before installation
Even in regions with similar terrain, the types of roofs, their ages, and sunlight exposure vary from house to house. At Kakeru Koumuten Co., Ltd., we will check the type and condition of the roof and the site conditions before installation and propose plans for fixing methods, waterproofing arrangements, and scaffolding.
■ The annual sunshine hours in the neighboring Yokohama City is about 2,018 hours
According to the Japan Meteorological Agency’s average values (1991-2020), the annual sunshine hours in Yokohama City, which is adjacent to Yamato City, is about 2,018 hours. Monthly, August (about 206 hours) has the most sunshine, while June during the rainy season (about 136 hours) has the least.
Power generation varies by season and location, so conducting annual power generation simulations and selecting the capacity of storage batteries to match the times of high electricity usage is key.
Our company is based in Kanagawa Prefecture and handles many exterior construction and solar projects in Yamato 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 any sudden troubles!
Service Area in Yamato City
Kakeru Koumuten Co., Ltd. accepts requests for work throughout Kanagawa Prefecture and Tokyo.
Yamato City Area List
Yamato City Kamikusayanagi / Yamato City Kamikawada / Yamato City Sakuramori / Yamato City Shibuya / Yamato City Shimokusayanagi / Yamato City Shimotsuruma / Yamato City Shimokawada / Yamato City Kusayanagi / Yamato City Daikan / Yamato City Chuo / Yamato City Chuo Rinkan / Yamato City Chuo Rinkan Nishi / Yamato City Tsukiminoko / Yamato City Tsuruma / Yamato City Nishitsuruma / Yamato City Fukami / Yamato City Fukami Dai / Yamato City Fukami Higashi / Yamato City Fukami Nishi / Yamato City Fukuda / Yamato City Minami Rinkan / Yamato City Yanagihashi / Yamato City Yamato Higashi / Yamato City Yamato Minami / Yamato City Rinkan
・Please leave the exterior wall painting in Yamato City to Kakeru Koumuten!
・Please leave the roof renovation in Yamato City to Kakeru Koumuten!
・Please leave the exterior renovation in Yamato 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 points to consider!
・12 major manufacturers of solar power generation! Features and selection points are also introduced!
・What are the installation costs for solar power generation? Thorough explanation of tips to reduce costs!
・What are the suitable locations for installing solar power generation? Points for selecting installation locations are also introduced!
・Here is the introduction to solar power generation estimates!
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contact Kakeru Koumuten Co., Ltd.
Kakeru Koumuten is a young company whose team is, on average, in their late twenties, but our skills are second to none.
Our greatest strength is that we handle scaffolding, roofing and painting entirely in-house. In an industry where these tasks are usually divided among contractors, our complete service simplifies project management and helps keep costs down. Above all, if a problem arises, we respond promptly.
We proudly describe ourselves as the youngest and most helpful renovation company in Kanagawa!
