Leave Your Solar Panel Installation Work in Kamakura City, Kanagawa Prefecture to Kakeru Koumuten Co., Ltd.!
For solar panel and battery installation in
Kamakura City, Kanagawa Prefecture,
trust Kakeru Koumuten!
Kakeru Koumuten is a specialized exterior renovation company based in Aoba Ward, Yokohama City.
As a company strong in roofing work, we are entrusted withsolar panel installation and battery installation considering roofs and waterproofing!
“How to Choose a Solar Panel Contractor in Kamakura City”
“Costs for Solar Panel and Battery Installation”
“Subsidies Available for Solar System Installation in Kamakura 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 Kamakura City, Kanagawa Prefecture
- Roof Inspection Before Installing Solar Panels
- Subsidies and Grants That May Be Available in Kamakura City
- Price List for Solar Panel and Storage Battery Installation
- Breakdown of Installation Capacity, Equipment, and Labor 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 Kamakura City, Kanagawa Prefecture
- 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 Kamakura City
- If You Are Looking for a Solar Panel Installer in Kamakura City, Contact Kakeru Koumuten
- Characteristics of Kamakura City, Kanagawa Prefecture, and Points for Solar Installation
- Service Area in Kamakura City, Kanagawa Prefecture
Reasons Why Kakeru Koumuten is Chosen for Solar Panel Installation in Kamakura City, Kanagawa Prefecture
The reasons why our company is entrusted with solar panel installation by customers in Kamakura City, Kanagawa Prefecture include
the fact that Kakeru Koumuten has a base in Kanagawa Prefecture,
and our unique strengths in solar panel installation that cannot be imitated by other companies, which have received high praise from many customers.
so we would appreciate it if you could compare our estimates with those of other companies.
Because we are confident, we welcome multiple estimates!
1. We Can Also Handle Exterior Renovations Other Than Solar Panel Installation!
Troubles such as leaks that occur during solar panel installation may be caused by insufficient checks on the roof and waterproofing at the installation site.
Even if one is knowledgeable about solar panels, there may be cases where the roof and waterproofing at the installation site are outside their expertise, so caution is necessary.
It is reassuring to be knowledgeable about the roof to avoid maintenance and troubles after installation!
Kakeru Koumuten Co., Ltd. is strong in roofing work and can also detach and attach solar panels in-house, allowing for quick responses to maintenance and urgent troubles after solar panel installation!
2.Facilities Specialized in Exterior Renovation
Kakeru Koumuten Co., Ltd. has organized the following warehouses and material storage areas to provide low-cost, high-quality solar work and exterior renovations.
We have established five bases centered around Yokohama City, Kanagawa Prefecture for material storage and showrooms.
In-house Ownership of Scaffolding Materials
To ensure safety during work on the roof, we own the necessary scaffolding materials for temporary scaffolding based on construction conditions, allowing us to assemble scaffolding ourselves.
By conducting scaffolding work with our own scaffolding team instead of outsourcing, we can also reduce the cost of scaffolding work.
We have scaffolding materials for approximately 50 single-family homes!
In the residential area of Kamakura City, surrounded by mountain ridges and with houses lined up in the valleys known as “yatō,” our scaffolding team plans scaffolding tailored to the site.
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, enabling us torespond quickly in emergencies!
Sorting and transportation of 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 the roofing materials!
It is also possible to simulate the revenue and installation costs when introducing solar panels!
Since roofing and exterior wall work often accompany each other, we also have samples of roofing materials and models that show the structure, allowing for detailed explanations!
3.Complete In-House Construction
One of Kakeru Koumuten’s major strengths is complete in-house construction.
By having Kakeru Koumuten handle everything from inquiries to project completion in a consistent manner, we can keep costs down while providing high-quality roof remodeling.
Additionally, one representative will assist you from the estimate to the completion of the work.
Since the same person will handle sales and construction management, smooth communication is possible.
We can provide consistent in-house construction from temporary scaffolding installation to exterior wall painting and roof remodeling!
4. Various Permits and Skilled Workers
We have obtained construction industry permits and permits for industrial waste collection and transportation!
We also have nationally certified sheet metal and painting technicians, and we are confident in our construction skills.
We can also handle large-scale roofing work for factories and other facilities!
5. Warranty and Aftercare
In addition to the manufacturer’s warranty, solar panel installation work comes with our own workmanship warranty (leakage warranty)!
(The workmanship warranty for solar panel installation is 10 years. Depending on the condition of the roof before installation, we may not be able to provide a warranty unless roof renovation is performed. The workmanship warranty is separate from the manufacturer’s product warranty, and the coverage and conditions vary depending on the warranty details.)
Aftercare maintenance is available annually, and we send out notification DM every year.
If you have any questions about the warranty, please click on the image above!
6. Flexible and Prompt Response
Our company is equipped to handle various roof troubles and situations.
Even if you cannot access the roof at high places, we can respond using a drone!
During leakage investigations, we can also conduct inspections using a thermal imaging camera.
If the power generation of the solar panels decreases due to dirt, we can also provide cleaning with a specialized brush.
We will respond according to your preferences.
7. Human Resource Development
We create various roof models for skill improvement 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 Clear Materials and Simulations
At Kakeru Koumuten Co., Ltd., we provide not only “estimates,” “layout diagrams,” and “power generation simulations” but also a “solar installation guidebook” and a “financial simulation” that takes into account loan interest rates and electricity costs.
The financial simulation can project cumulative income and expenses over 20 to 30 years.
Even customers who are not familiar with solar installations will find our materials easy to understand, including important points and potential drawbacks!
We encourage you to obtain comparative estimates and review plans from other companies!
Roof Inspection Before Installing Solar Panels
Once solar panels are installed, they will remain on the roof for 20 to 30 years.
It is crucial to confirm “whether it is safe to install them directly on the current roof” before installation, as this is the key point to prevent leaks and unnecessary expenses!
Kakeru Koumuten Co., Ltd., which specializes in roofing work, has summarized the items to check before installation.
| 1. Type of roofing material and age | The method of securing the panels varies depending on the roofing material, such as slate, tiles, metal roofs, or flat roofs (roof waterproofing). If the remaining lifespan of the roofing material is short, we may suggest a roof renovation first. |
| 2. Condition of the substrate and waterproof sheet | If the sheathing or roofing (waterproof sheet) beneath the roofing material is damaged, it can affect the fastening strength and waterproofing. We will also check for 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 verify it with the power generation simulation. |
| 4. Shape of the roof and installable area | The shape and size of the roof determine the number of panels that can be installed (installation capacity). The number of panels that can be installed varies depending on their size, so we will compare based on the total output of the roof. |
| 5. Method of securing and waterproofing details | We will confirm whether the method involves drilling holes in the roofing material or securing it with brackets. The method of securing varies by technique, so please check the waterproofing treatment of the fastening parts during the estimate. |
| 6. Weight of the roof | The roof will become heavier due to the panels. After investigating the existing roof, substrate, and load-bearing capacity, replacing with lighter roofing materials may be an option if necessary. |
| 7. Location of equipment installation and wiring | We will check the installation location of the power conditioner and storage battery, as well as the wiring route to the distribution board. The length of the wiring also affects costs. |
Securing Methods and Checkpoints by Roofing Material
| Roof Material | Main Fixing Method | Pre-Installation Check Points |
|---|---|---|
| Slate Roof | Varies by method (e.g., fixing brackets to roof material and substrate with screws) | Waterproof treatment of fixing parts, cracks or deterioration of slate, condition of substrate. If deterioration is significant, consider roof overlay (cover method) or replacement first. |
| Tile Roof | Fixed with brackets and methods suited to the type of tile (even methods that do not drill holes in the tiles will secure to the substrate) | Type and condition of tiles, substrate, load-bearing capacity. Depending on the investigation results, there may be methods to replace with 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 condition of waterproof layer, waterproofing around the frame. Consider in conjunction with the timing of waterproofing work. |
If you plan to renovate the roof 10 to 20 years after installation, there will be additional costs for removing and reinstalling solar panels. If the roof is deteriorating, renovating to a highly durable roofing material before installation may help reduce costs in the long run.
Kakeru Koumuten Co., Ltd. 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 Kamakura City, Kanagawa Prefecture
PotentialSubsidies and Grants in Kamakura City, Kanagawa Prefecture
When introducing solar panels or storage batteries in Kamakura City, there is a possibility of being eligible for programs from “the national government,” “Kanagawa Prefecture,” and “Kamakura City.”
The following information is based on the official pages of each program as of October 6, 2026. The application status may change due to budget and recruitment periods, so please check the latest information before contracting or starting work.
Eligibility Conditions and Application Timing for Subsidy Programs
| Program | Main Eligibility Conditions | Subsidy Amount | Application Period & Status |
|---|---|---|---|
| Kamakura City “Reiwa 8 Year Residential Renewable Energy and Energy-Saving Equipment Installation Subsidy” | Installed in a residence where the applicant resides and owns/uses the equipment (no tax arrears). Solar power generation must be certified under the FIT system. Storage batteries must be stationary lithium-ion systems, and applications can be made for storage batteries only. Application must be submitted before starting installation work. | Solar: 10,000 yen per kW (maximum 50,000 yen) Storage Battery: Maximum 50,000 yen V2H: Maximum 30,000 yen, Enefarm: Maximum 40,000 yen, ZEH Additions: 50,000 yen (conditions apply) |
Applications are being accepted from April 1, 2026 (budget of 6 million yen, execution rate as of September 30, 2026, is about 72%. Until the budget is reached) Application deadline is March 1, 2027, and performance report is due by March 31, 2027. |
| Kamakura City “Accelerated Measures Subsidy for Key Projects” (for households) | Solar power generation that self-consumes more than 30% of the electricity generated without certification under FIT or FIP. Storage batteries can only be introduced simultaneously with solar power. Cannot be combined with the city’s residential renewable energy subsidy. | Solar: 70,000 yen/kW Storage Battery: One-third of the cost (maximum 141,000 yen/kWh) |
The household program reached its budget with applications on June 17, 2026, and is now closed (currently, applications cannot be made). |
| Kanagawa Prefecture “Reiwa 8 Year Kanagawa Prefecture Residential Solar Power and Storage Battery Installation Subsidy” | Must install both solar power and storage batteries in a single-family or multi-family residence that ensures seismic performance within the prefecture. The application must be made by the applicant, and construction can begin after the grant decision. | Solar: 70,000 yen/kW Storage Battery: 150,000 yen per unit |
Phase 1: May 11, 2026 – June 30, 2026 Phase 2: September 7, 2026 – September 30, 2026 (first-come, first-served) Phase 2 has reached its application deadline. Please check the prefecture’s official page for future recruitment. |
| National “DR Household Storage Battery Project” (Reiwa 7 Year Supplement) | Newly introduce household storage systems that can be used for DR (demand response) with registered products. | Calculated based on an initial effective capacity of 34,500 yen per kWh (subsidy rate within 3/10, maximum 600,000 yen per application). | As of May 29, 2026, the budget has been reached, and public recruitment has ended (currently, applications cannot be made). |
| National “Mirai Eco Housing 2026 Project” (Renovation) | Storage batteries are one of the eligible facilities, but must be combined with essential works such as insulation renovation of windows (openings) and the structure; applications cannot be made for just the installation of storage batteries. Solar panels are not included as eligible facilities. | Storage Battery: 96,000 yen per unit | Budget will end once the limit is reached. Please check the official website for the application status. |
| 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 10kW or more, for business facilities, and equipment not certified under FIT/FIP, etc. | Solar power: 80,000 yen/kW, etc. Storage systems: 50,000 yen/kWh (up to 5 million yen) |
Applications will close on September 3, 2026 (when the application amount reaches the budget amount) |
For Kamakura City’s residential subsidies, applications must be made before starting installation work, while Kanagawa Prefecture’s residential subsidies require work to begin after receiving “grant approval”. If work begins beforehand, it will be ineligible. Additionally, the two subsidies from Kamakura City (subsidy for residential renewable energy and energy-saving equipment installation and the priority measures acceleration project subsidy) cannot be used together. The eligibility for combining city and prefectural subsidies must be confirmed for each system. Receiving a subsidy is not guaranteed upon application, so please confirm before contracting and starting work.
At Kakeru Koumuten, we will guide you on the eligibility conditions and business requirements for each system after confirming them.
Kamakura City “Reiwa 8 Year Residential Renewable Energy and Energy-Saving Equipment Installation Subsidy”
Kamakura City provides subsidies for those installing solar power generation systems and storage batteries in residential properties within the city. Eligible applicants are those who install equipment in their own residences within the city and own and use it, with conditions including no delinquency on city taxes and that the equipment is unused.
The subsidy amount is 10,000 yen per 1kW of nominal maximum output for solar power (up to 50,000 yen), and up to 50,000 yen for storage batteries. Solar power must be certified under the FIT system, and applications for storage batteries can be made even if not installed simultaneously with solar power. Additionally, there are add-ons for V2H (up to 30,000 yen), Enefarm (up to 40,000 yen), and ZEH, etc. (50,000 yen).
The budget is 6 million yen, and as of September 30, 2026, the execution rate is approximately 72%. Applications will close once the budget is reached, so if you are considering applying, please check early. Applications must be made before starting installation work, and grant applications are accepted until March 1, 2027.
👉 Click here for the official Kamakura City page
Kamakura City “Priority Measures Acceleration Project Subsidy” (Solar Power Generation Equipment and Storage Batteries)
Kamakura City also offers subsidies for solar power generation that does not receive FIT/FIP certification and for storage batteries installed simultaneously with solar power for self-consumption. For households, the subsidy is 70,000 yen per 1kW for solar power and one-third of the cost for storage batteries (up to 141,000 yen/kWh).
However, the household program reached its budget with applications on June 17, 2026, and has closed. Applications for business use by small and medium enterprises are still being accepted, but the execution rate is approximately 97% (as of October 2, 2026). If you are considering applying for business use, please check the latest status on the city’s official page.
👉 Click here for the official Kamakura City page
National Subsidy “DR Home Battery Project (Support Project for Home Storage Systems for DR Resource Introduction)”
The government has been implementing the “DR Home Battery Project” to support the installation of home storage batteries.
This program targets those who are newly introducing registered storage systems that can be utilized for demand response (DR), and for the fiscal year 2025 supplementary budget, the subsidy amount is determined based on a standard amount of 34,500 JPY per initial effective capacity of 1 kWh, with a subsidy rate of up to 30% and a maximum of 600,000 JPY per application. There are also conditions such as that contracts or orders made before the grant decision are not eligible.
However, the supplementary budget for fiscal year 2025 reached its budget on May 29, 2026, and the public recruitment has ended (the previous fiscal year’s supplementary budget also ended on July 2, 2025). Applications are currently not accepted, so please check the official site for future public recruitment.
Additionally, there are currently no subsidies confirmed for the installation of solar panels for existing homes.
👉 Click here for the official site of the DR Home Battery Project
Kanagawa Prefecture “Fiscal Year 2026 Kanagawa Prefecture Subsidy for Residential Solar Power Generation and Storage Battery Installation Costs”
Kanagawa Prefecture provides subsidies for those who install both “solar panels” and “storage batteries” in their homes.
The subsidy details are 70,000 JPY per 1 kW of solar power generation output and 150,000 JPY per storage system.
For example, if you install a 4 kW solar panel and one storage battery, the subsidy amount would be calculated as 4 kW × 70,000 JPY + 150,000 JPY = 430,000 JPY.
The storage 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 (proxy applications by construction contractors are not allowed). The eligible homes must also ensure seismic performance. The compatibility with other subsidy programs may vary by program, so please confirm.
For fiscal year 2026, the first phase (May 11 to June 30) and the second phase (September 7 to September 30, first-come-first-served) have been accepted, and the second phase is approaching its deadline. For future recruitment, please check the official page of Kanagawa Prefecture.
👉 Click here for the official page of Kanagawa Prefecture
Kanagawa Prefecture “Fiscal Year 2026 Kanagawa Prefecture Subsidy for Self-Consumption Type Renewable Energy Installation Costs” (for businesses)
Kanagawa Prefecture also provides subsidies for businesses that install “self-consumption type” facilities that use electricity generated from solar panels.
The target is corporations or individual business operators filing blue returns, and the introduction to individual residences is not eligible.
Solar power generation must have a generation 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), among other details.
As the application amount reached the budget amount for Reiwa 8, applications were closed on September 3, 2026.
For businesses considering the installation of solar panels on commercial buildings in Kamakura City, please check the official page of Kanagawa Prefecture for the next recruitment.
👉 Click here for details
Solar Panel Installation & Storage Battery Installation Price List
⇧Service Menu | Click here for costs related to solar panel removal & water heater removal
Breakdown of Installation Capacity, Equipment, and Construction Costs
The costs for solar panels and storage batteries should be confirmed separately as “Equipment Costs (Device Costs)” and “Construction Costs.”
Even for the same “Complete Solar Panel Installation,” the amount can vary significantly depending on the installation capacity, equipment grade, and roof condition.
Understanding Installation Capacity (kW) and Battery Capacity (kWh)
The installation capacity of solar panels is determined by “Output of One Panel (W) × Number of Panels”, with the unit being kW (kilowatts). Storage batteries are compared based on the amount of electricity they can store, measured 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 3-5 kW and 1,200,000 JPY to 1,900,000 JPY for 6-10 kW. (These are just estimated amounts and can vary based on wiring length, scaffolding range, existing roofing materials, panel layout, etc.)
▶ Installation Menu | Costs for Solar Panel and Storage Battery Installation
Items to Confirm in the Estimate (Cost Verification)
When comparing estimates, it is common to compare different capacities and equipment by only looking at the amounts. Please check if the following items are clearly stated in each company’s estimate!
| 1. Solar Panels | Manufacturer, model number, output per panel (W), number of panels, total installation capacity (kW) are documented. |
| 2. Power Conditioner | Manufacturer, model number, capacity, number of units, installation location (indoor/outdoor). Also check if it is a type that controls in conjunction with a storage battery. |
| 3. Storage Battery | Manufacturer, model number, capacity (kWh), range of use during power outages (entire house or specific circuits), installation location. |
| 4. Mounting Frame and Hardware | Name of the hardware suitable for the roofing material and the method of securing it (whether it involves drilling holes or clamping 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 the fixed points, whether necessary roof repairs and substrate reinforcements are included. |
| 7. Applications | Extent of support for applications to the power company, certification application for selling electricity (FIT), and subsidy applications. |
| 8. Scaffolding | Scope and quantity of scaffolding. If roofing work and exterior painting are done simultaneously, confirm 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 prices are tax-inclusive or tax-exclusive, conditions under which additional costs may arise, details and duration of manufacturer warranty and workmanship warranty. |
If the capacities differ, both the price and power generation will change. Kakeru Koumuten Co., Ltd. welcome comparisons, so if you bring estimates from other companies, we will explain the differences for each item!
Self-Estimate and Profit and Loss Simulator for Solar Power Generation
With the simulator above,
you can obtain an approximate estimate and a profit and loss simulation 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 approximate estimate and profit and loss simulation!
*The simulation results are approximate. Actual profit and loss may vary based on assumptions such as electricity rates, self-consumption ratios, selling prices, and costs for equipment inspection or replacement.
Customer Feedback
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customer reviews
Asao-ku, Kawasaki City | We received reviews about the ridge cap and rain gutter replacement work!
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customer reviews
Kohoku-ku, Yokohama | We received reviews about the roof overlay (cover method)!
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customer reviews
Kohoku-ku, Yokohama | We Received Reviews About Exterior Painting!
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customer reviews
Hodogaya-ku, Yokohama | We received reviews about our exterior fence construction!
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customer reviews
Tsurumi-ku, Yokohama | We received reviews about roof and exterior wall painting, as well as metalwork and rain gutter replacement work!
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customer reviews
Higashiyamato City, Tokyo | We received reviews about exterior painting and roof overlay (cover method)!
Case Studies of Solar Panel Installation
| Construction Details |
| Solar Panel Installation Battery Installation |
| Existing Roofing Material |
| Horizontal Metal Roof (Super Galtect) |
| Installation Capacity |
| Solar Panel: 4.3kW Battery: 5kWh |
| Base Mounting Hardware Used |
| Niigata Manufactured / Aluminum Catch Type Hardware |
| Fixing Method & Waterproofing 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 installation of solar panels and storage batteries. I heard that grants are available, and I would like to know how much can be provided. |
Our Proposal
We visited to provide an estimate and created a layout diagram for the solar panels from the drawings!
The layout diagram shows the arrangement 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 grants that will be provided, and we explained this to the customer along with the estimate!
How to Choose a Solar Panel Installation Contractor in Kamakura City, Kanagawa Prefecture
There are many solar panel installation companies that serve Kamakura City, Kanagawa Prefecture, and you may be unsure which company to choose.
Therefore, when requesting solar panel installation and battery storage installation work, let’s check the following four points.
● Have extensive knowledge not only about solar panels but also about roofs
● Confirm the existence of warranties and after-sales maintenance
● Obtain estimates from multiple companies (three companies is a guideline)
● Check if they provide support for subsidy applications
By confirming the above four points, you will be able to choose a reliable company.
Knowledge about roofs as well as solar panels
Improper installation of solar panels can be caused by a lack of knowledge and verification regarding roofs and waterproofing.
While knowledge about solar panels is certainly important, understanding the roof and waterproofing at the installation site of the solar panels is also crucial.
⚠︎Examples of troubles caused by insufficient verification of roofs and waterproofing
・Solar panels were installed on a severely deteriorated roof, leading to leaks
・Solar panels were installed on a roof with a short lifespan, requiring a renovation to detach and reattach the solar panels within a few years
・Misjudged the type of waterproofing and performed incorrect processing, 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 Verification Before Installing Solar Panels” in this article
Confirm the existence of warranties and after-sales maintenance
When choosing a solar installation company, let’s confirm the existence of warranties. It is important to check not only the duration of the warranty but also the scope, exclusions, and cost conditions.
Solar panels and battery storage units come with manufacturer warranties, but also check for the existence of workmanship warranties in case leaks occur after installation!
For companies that offer workmanship warranties, if leaks occur after installation, they may cover the repairs under the warranty, provided it is within the warranty period and conditions.
Additionally, some contractors offer after-sales service separate from warranties, so be sure to check if the contractor you are considering has after-sales service.
Changes or damage on the roof may occur in areas that are not visible, so you may not notice them yourself.
By conducting inspections during after-sales maintenance, you can easily prevent major repairs or breakdowns by detecting issues early!
Kakeru Koumuten Co., Ltd. provides a leak warranty as part of the workmanship warranty for solar panel installations. (The warranty for solar panel installations is 10 years, and depending on the condition of the roof before installation, a roof renovation may be required to provide the warranty.)
We also conduct after-sales maintenance and send out DM every year!
Please check the DM, and if you wish, we will visit you for after-sales maintenance!
Obtain estimates from multiple contractors (3 companies as a guideline)
When requesting solar panel installation, be sure to obtain estimates from multiple contractors.
Even for the same manufacturer and the same work content, costs may vary, and warranties and after-sales services may differ.
Additionally, obtaining multiple estimates makes it easier to negotiate prices.
To request from your desired contractor at a lower price, we recommend obtaining estimates from multiple contractors.
When comparing estimates,
“Check the estimate items”
“Type of solar panel”
“Warranties and after-sales services”
and make a detailed comparison to make your judgment! If the rank of auxiliary materials is low or if steps are skipped, costs can be reduced, so avoid making decisions based solely on price!
▶ Go to “Installation Capacity and Breakdown of Equipment and Construction Costs” in this article
Check if they provide support for subsidy applications
Subsidies may be available for solar panel installations and battery installations, but if the order of procedures is incorrect or if there are deficiencies in the documents, the subsidy may not be granted.
For systems like Kanagawa Prefecture’s housing subsidies, where contractors cannot apply on behalf of clients, it is reassuring to have a contractor who can support you in preparing necessary documents and the flow of procedures.
Be sure to 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 a review! (The flow of procedures varies by system)
▶ To “Subsidies and Grants That May Be Applicable in Kamakura City” within this Article
Benefits of Introducing Solar Power Systems
The benefits of introducing solar panels are summarized in the following 5 points!
Benefit 1: Economic Advantage
The biggest advantage of introducing solar panels is the economic benefit!
Although the selling price of electricity has decreased compared to 10 years ago, by consuming the generated electricity for personal use, you can reduce the amount of electricity purchased from the power company and gain benefits!
As electricity costs rise, the ability to cover 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 October 2025 onwards is 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-consume) rather than sell it, making the combination with a storage battery a viable option.
👉 Ministry of the Environment｜For purchase prices, periods, etc., click here
Benefit 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 amount through subsidies is a significant advantage!
In the case of Kamakura City, there may be subsidies available from the city and Kanagawa Prefecture, so please check the latest application status.
Benefit 3: Environmentally Friendly!
Solar power generation has low carbon dioxide emissions and reduces dependence on fossil fuels, contributing to the mitigation of global warming.
Solar panels themselves do not produce noise or exhaust gases during the generation process, making them an environmentally friendly method of power generation. (However, devices like power conditioners may have operational noise.)
Benefit 4: Expect Heat Insulation Effects!!
By installing the panels on the roof or rooftop, they block direct sunlight from hitting the roof.
Especially in summer, it can help reduce the rise in roof temperature, providing expected heat insulation effects!
(Note that this does not improve the building’s insulation performance itself.)
Benefit 5 Power can be used even during power outages!!
If a storage battery is installed, it becomes possible to use electricity even during emergencies such as power outages!
Even without a storage battery, if you have a power conditioner with autonomous operation capability, you may be able to use electricity from a dedicated outlet during daytime generation.
(Note that the devices, output, and duration that can be used during a power outage vary depending on the model and wiring method.)
What points should be noted when introducing solar power generation?
Next, we will explain the “three points to note” when installing solar panels!
Point 1 Maintenance costs can be incurred
A particularly overlooked maintenance cost is for the roof where solar panels are installed.
If you perform roof renovations 10 to 20 years later, there will be costs for removing and reattaching the solar panels.
If the existing roof is deteriorating, it is reassuring to renovate it with durable roofing materials before installing the solar panels!
Additionally, there will be costs for regular inspections of the equipment, repairs or replacements of the power conditioner, and updates due to the deterioration of the storage battery.
It would be reassuring to 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 in methods that fix hardware to the roofing material or substrate with screws, 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.)
Foundation Brackets for Horizontal Metal Roofs
Note 3: The Roof Becomes 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 be one option if necessary.
How to Choose Solar Panels?
There are many manufacturers of solar panels, and their output and costs vary.
It is not simply a matter of “This manufacturer has the best solar panels”; it is important to choose solar panels that are suitable for your life plan and building!
Here are some points to consider when comparing solar panels!
How to Choose 1: Compare Based on Total Roof Output
When installing solar panels on the roof, it is important to consider how much electricity can be generated in a limited area, and generating more electricity is always better!
Solar panels come in various sizes and outputs depending on the manufacturer.
For example, a 350W output panel and a 400W output panel may seem that the higher output panel is better at first glance.
However, if the size of the panels does not fit well on the roof, there may be cases where “20 panels of 350W can be installed” and “15 panels of 400W can be installed,” leading to different installation capacities on the same roof due to the size difference.
400W × 15 panels = 6kW (Total roof output)
350W × 20 panels = 7kW (Total roof output)
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 calculations are for total output (kW). The actual power generation (kWh) will vary depending on conditions such as roof orientation, slope, and shading.
How to Choose 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 itself.
Choosing solar panels while considering the degradation rate, not just the initial output, will lead to a regret-free decision!
How to Choose 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 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 Kamakura City
We have compiled frequently asked questions from customers considering the installation of solar panels and storage batteries in Kamakura City. (Tap to open the answers)
How much does it cost to install solar panels and storage batteries in Kamakura City, Kanagawa Prefecture?
The cost varies depending on the installation capacity, equipment, and condition of the roof. In the above construction example (solar panel 4.3kW + storage battery, completed in April 2025), it was 2.2 million yen to 2.3 million yen.
Guidelines for different capacities are published on the solar panel installation and storage battery installation pricing page. We will create a layout diagram from the drawings and on-site survey and provide a free estimate!
Are there any subsidies available for solar power and storage battery installation in Kamakura City?
As of October 6, 2026, Kamakura City’s “Subsidy for Installation Costs of Residential Renewable Energy and Energy-Saving Equipment” (10,000 yen per 1kW of solar power, with a maximum of 50,000 yen; storage battery has a maximum of 50,000 yen) continues to accept applications until the budget is reached, and the execution rate as of September 30, 2026, is approximately 72%. On the other hand, the subsidy for the city’s key measures acceleration project for households has ended. The Kanagawa Prefecture subsidy (70,000 yen/kW for solar power and 150,000 yen per unit for storage batteries) is approaching the application deadline for the second phase of the Reiwa 8 fiscal year, and the national DR household storage battery project has ended its public recruitment.
Since the application status may change, please refer to the subsidies and grants section and consult with us before signing a contract.
Can I apply for subsidies after the construction is completed?
For many programs, procedures are required before construction. The application for Kamakura City’s residential subsidy must be made “before starting the installation work,” and for Kanagawa Prefecture’s subsidy, “construction must begin after the grant decision,” meaning that if you install first, you 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. The method of securing the panels varies by construction method, and when securing 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 within 10 to 20 years after installation, there will be additional costs for removing and reinstalling solar panels. If the remaining lifespan of the roof is short, it may be more cost-effective to renovate with durable roofing materials before installation.
Please consult us about the installation process after confirming the condition of the roof through a site survey!
Should I install a storage battery together with the solar panels?
If you want to use the generated electricity at night or prepare for power outages, simultaneous installation is recommended. The selling price for electricity will be 8.3 yen/kWh after the fifth year, making it more advantageous to use it at home rather than selling it.
Additionally, Kanagawa Prefecture’s subsidy requires the simultaneous introduction of solar panels and storage batteries, while Kamakura City’s residential subsidy can be applied for with just the storage battery (up to 50,000 yen). You can compare “solar panels only” and “solar panels + storage battery” through a financial simulation.
How many kW can be installed on my roof? Is it okay for north-facing roofs or roofs with shadows?
The capacity that can be installed varies depending on the shape, orientation, and size of the roof. At Kakeru Koumuten Co., Ltd., we create a layout diagram from the drawings and site survey, and provide you with the installation capacity and power generation simulation.
Kamakura City is surrounded by mountains on three sides, and many houses are built in areas embraced by the green of the mountains, with the shading from surrounding mountains and trees varying from house to house. You can check the expected power generation through the power generation simulation.
How long is the construction period?
For the above construction example (solar panels 4.3 kW + storage battery), it took about 3 days. The duration may vary if roofing work is done simultaneously or depending on the shape of the roof and installation capacity.
Please note that there will be an additional period for applying for subsidies and to the power company, so please consult us as soon as possible.
What is the current selling price (FIT)?
For residential use (under 10 kW), from the certification after October 2025, the first 4 years will be 24 yen/kWh, and from the 5th to the 10th year it will be 8.3 yen/kWh, with the same price applied in the 2026 fiscal year.
The idea is to recover the initial costs more quickly in the first 4 years and then focus on self-consumption. Kakeru Koumuten Co., Ltd. provides a financial simulation that takes into account loan interest rates and electricity costs.
Can you handle maintenance and inspections after installation?
Yes, we can. Kakeru Koumuten Co., Ltd. sends out annual after-maintenance DM notifications and visits customers who wish for inspections. We can also clean solar panels with a special brush if the power generation decreases due to dirt.
The roof is a part that is difficult to check 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, it is possible. Kakeru Koumuten Co., Ltd. can detach and reattach solar panels in-house, allowing us to remove the panels, perform roof overlay (cover method) or re-roofing, and then reinstall them consistently. The removed panels can be stored in our own warehouse.
For costs, please refer to the solar panel detachment and water heater removal pricing page.
If you are looking for a solar panel installation company in Kamakura City, please consult Kakeru Koumuten
Our company handles a wide range of exterior renovations, including solar panel installations, roof work, and exterior wall work in Kamakura City, Kanagawa Prefecture.
We have received requests from many customers, including renovation companies and real estate agencies, who have contacted us!
Kakeru Koumuten promises “high-quality renovations at low costs”, and we have received great feedback from many customers.
We continue to update our construction achievements every year, and we will strive to improve quality to satisfy even more customers in the future.
Our company is capable of performing all exterior renovations, not only roof overlay work and re-roofing but also partial roof repairs, exterior painting, and exterior wall cover methods.
We are also happy to handle small jobs such as partial repairs and rain gutter cleaning!
In urgent cases such as leak repairs, we may be able to provide emergency measures without setting up scaffolding, as long as safety can be ensured, so please consult us!
“I want to know 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 the customer’s position and will propose the optimal construction plan!
We are confident that we will not be outdone in terms of cost, quality, and efficiency compared to other companies in exterior work!
We are confident, so we welcome competitive estimates!
Estimates are completely free, and if our company is found to be inferior to others, you are free to decline!
Characteristics of Kamakura City, Kanagawa Prefecture and Points for Solar Work
Kamakura City is surrounded by mountains on three sides, with the sea spreading to the south. Houses are lined up in the valleys called “yato,” and the entire city is designated as a landscape planning area.
We have summarized the topography and landscape rules of Kamakura City, as well as points to consider when installing solar panels and storage batteries below. (Tap to open)
View the characteristics of Kamakura City and points for solar construction
■ A topography surrounded by mountains. It is important to check the shadows and roof orientation of houses in the valleys
Kamakura City’s Historical Landscape Maintenance and Improvement Plan (Official City Document) states that most of Kamakura City is occupied by mountain ridges and plateaus, with little flat land. According to Information about Yato (Official City Document), valleys cut into the mountains are called “yato,” and it is mentioned that houses are now lined up deep within the valleys.
In residences surrounded by mountains, the shadows cast by the mountains and trees vary from house to house. Kakeru Koumuten Co., Ltd. creates layout diagrams based on the drawings and the actual site conditions, allowing you to confirm through power generation simulations.
■ The entire city is a landscape planning area. Consider the color and installation position of the panels
Considerations for Landscape When Installing Solar Power Systems in Kamakura City (Official City Document) states that the entire city of Kamakura is a landscape planning area, and care for the landscape is necessary during installation. It is suggested to choose products that are the same color as the roof, dark products with little gloss and reflection, products that are thin and appear integrated with the roof, avoid frames with strong gloss, and place them in positions that are not prominent from the street.
The type and arrangement of the panels will be selected while considering the balance between power generation and landscape considerations. Please consult us during the estimation process.
■ Approximately 55.5% of the city is designated as a scenic area. If exterior painting is to be done simultaneously, prior confirmation is necessary
Kamakura City Scenic Area Ordinance (Official City Document) states that approximately 2,194 hectares (about 55.5% of the city) are designated as scenic areas, and permission from the mayor is required for new construction, expansion, or changes in the color of exterior walls within these areas. If you plan to do exterior painting along with solar panel installation, it is important to confirm whether your residence is located in a scenic area beforehand. Depending on the scale and method of installation, procedures may also be necessary, so please check according to the city’s guidelines.
■ Marine climate. For houses close to the sea, check the installation conditions of the equipment
According to the city’s Historical Landscape Maintenance and Improvement Plan, Kamakura City is characterized by a marine climate influenced by Sagami Bay to the south. In areas close to the sea, the installation conditions for salt damage areas set by manufacturers vary by model, so please check the installation location and model conditions during the estimation process. We will also ensure waterproofing of the roof, taking into account the rainy season.
■ Annual sunshine hours are approximately 2,000 hours
City’s Current Situation Report (Official City Document) states that Kamakura City has an annual sunshine duration of about 2,000 hours, making it suitable for solar power generation. The average temperature is 16.4℃, and the annual precipitation is 1,372.0mm.
The amount of electricity generated varies depending on the season and roof conditions, so conducting an annual power generation simulation and selecting the capacity of storage batteries to match the times of high electricity usage are key points.
■ Check the Roof Condition According to the Age of the Building
The same document indicates that approximately 58% of residential buildings in the city are single-family homes, about 67% are wooden houses, and about 33% were built before 1980 (Showa 55). For homes that have aged, it is important to check the condition of the roofing materials and substrate before installing solar panels. Depending on the roof’s condition, installing them simultaneously with roof renovations can reduce future costs for removing and reinstalling solar panels.
■ Roofs Near Green Mountains Require Attention to Leaves and Dirt
For homes close to green mountains, falling leaves and dirt on the roof can affect power generation. Kakeru Koumuten Co., Ltd. can provide solar panel cleaning with specialized brushes, as well as rain gutter cleaning services.
Our company is based in Kanagawa Prefecture and has extensive experience in exterior construction and solar power projects in Kamakura 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 for any urgent issues!
Service Area in Kamakura City, Kanagawa Prefecture
Kakeru Koumuten Co., Ltd. accepts requests throughout Kanagawa Prefecture and the entirety of Tokyo.
List of Areas in Kamakura City, Kanagawa Prefecture
Inamuragasaki, Kamakura City / Imaizumi, Kamakura City / Imaizumidai, Kamakura City / Iwase, Kamakura City / Ueki, Kamakura City / Ougigaya, Kamakura City / Ofuna, Kamakura City / Omachi, Kamakura City / Okamoto, Kamakura City / Onarimachi, Kamakura City / Kajiwara, Kamakura City / Kamakurayama, Kamakura City / Kamiyacho, Kamakura City / Koshigoe, Kamakura City / Kobukurodani, Kamakura City / Komachi, Kamakura City / Gokurakuji, Kamakura City / Sakanoshita, Kamakura City / Sasame, Kamakura City / Zaimokuzaka, Kamakura City / Shichirigahama, Kamakura City / Shichirigahama Higashi, Kamakura City / Shiromae, Kamakura City / Juunisho, Kamakura City / Jyoumyouji, Kamakura City / Sekiya, Kamakura City / Takano, Kamakura City / Tamagawa, Kamakura City / Dai, Kamakura City / Tsu, Kamakura City / Tsu Nishi, Kamakura City / Tehiro, Kamakura City / Terabun, Kamakura City / Tokiwadai, Kamakura City / Nikaido, Kamakura City / Nishikamakura, Kamakura City / Nishimikado, Kamakura City / Hase, Kamakura City / Fueita, Kamakura City / Yamazaki, Kamakura City / Yamanouchi, Kamakura City / Yuigahama, Kamakura City / Yukinoshita, Kamakura City
・Trust Kakeru Koumuten for exterior wall painting in Kamakura, Kanagawa!
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・Trust Kakeru Koumuten for exterior renovations in Kamakura, Kanagawa!
・Kakeru Koumuten Co., Ltd. construction achievements
・Kakeru Koumuten Co., Ltd. aftercare services
・Kakeru Koumuten Co., Ltd. construction menu and price list
・Kakeru Koumuten Co., Ltd. staff blog and announcements
・Explaining the importance of comparison estimates and key points!
・Top 12 solar power generation manufacturers! Features and selection tips included!
・What are the installation costs for solar power generation? Tips for reducing costs explained thoroughly!
・What are the best locations for solar power installation? Key points for site selection included!
・Find out about solar power generation estimates here!
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contact Kakeru Koumuten Co., Ltd.
Kakeru Koumuten is a young company whose team is, on average, in their late twenties, but our skills are second to none.
Our greatest strength is that we handle scaffolding, roofing and painting entirely in-house. In an industry where these tasks are usually divided among contractors, our complete service simplifies project management and helps keep costs down. Above all, if a problem arises, we respond promptly.
We proudly describe ourselves as the youngest and most helpful renovation company in Kanagawa!
