Leave Your Solar Panel Installation Work in Asahi, Yokohama City to Kakeru Koumuten Co., Ltd.!
For solar panel and battery installation in
Asahi Ward, Yokohama,
trust Kakeru Koumuten!
Kakeru Koumuten is a specialized exterior renovation company headquartered in Aoba Ward, Yokohama, with a material storage site in Kamikawai-cho, Asahi Ward.
As a company strong in roofing work, we are entrusted with solar panel and battery installation considering roofing and waterproofing!
“How to Choose a Solar Panel Contractor in Asahi Ward”
“Costs for Solar Panel and Battery Installation”
“Subsidies Available for Solar System Installation in Asahi Ward”
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 obtaining estimates from about three companies!
Table of Contents (tap to open/close)
- Reasons Why Kakeru Koumuten is Chosen for Solar Panel Installation in Asahi Ward, Yokohama
- Roof Inspection Before Installing Solar Panels
- Possible Subsidies and Grants Available in Asahi Ward
- Price List for Solar Panel and Storage Battery Installation
- Breakdown of Installation Capacity, Equipment, and Construction Costs
- Self-Estimate and Profitability Simulator for Solar Power Generation
- Customer Testimonials
- Case Studies of Solar Panel Installations
- How to Choose a Solar Panel Installation Company in Asahi Ward, Yokohama
- 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 Asahi Ward
- If You’re Looking for a Solar Panel Installation Company in Asahi Ward, Contact Kakeru Koumuten
- Characteristics of Asahi Ward, Yokohama and Key Points for Solar Work
- Service Area in Asahi Ward, Yokohama
Reasons Why Kakeru Koumuten is Chosen for Solar Panel Installation in Asahi Ward, Yokohama
The reasons why our company is entrusted with solar panel installation by customers in Asahi Ward, Yokohama
One reason is that Kakeru Koumuten has a base in the same city of Yokohama,
and we have unique strengths in solar panel installation that cannot be imitated by other companies, which has received high praise from many customers.
so we would appreciate it if you could compare our estimates with those of other companies.
Because we are confident, we welcome estimates from any number of companies!
1. We Also Handle Exterior Renovations Other Than Solar Panel Installation!
Problems such as leaks that occur during solar panel installation may be caused by insufficient checks on the roof and waterproofing at the installation site.
Even if one is knowledgeable about solar panels, there are cases where the roof and waterproofing at the installation site are outside their expertise, so caution is necessary.
It is reassuring to have knowledge 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 solar work and exterior renovations at low cost and high quality.
We have established five bases centered in 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 and can assemble scaffolding ourselves.
By performing scaffolding work with our own scaffolding team instead of outsourcing, we can also cut costs for scaffolding work.
We have scaffolding materials for approximately 50 single-family homes!
Even in the hilly residential area of Asahi Ward, our own scaffolding team plans the scaffolding to fit 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 stock of roofing materials, so we canrespond 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 remodeling 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 provide samples of roofing materials and models that show the structure, allowing for detailed explanations!
3.All Work Performed by Our Own Team
One of Kakeru Koumuten’s major strengths is all work performed by our own team.
By maintaining 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 person in charge does not change, whether it’s sales or construction management, smooth communication is possible.
We can perform consistent in-house work from temporary scaffolding installation to exterior wall painting and 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 workers and painting technicians, and we are confident in our construction skills.
We are capable of handling large-scale roofing projects such as factories!
5. Warranty and Aftercare
In addition to the manufacturer’s warranty, our 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 a roof renovation is performed. The workmanship warranty is separate from the manufacturer’s product warranty, and the scope and conditions vary depending on the warranty details.)
Aftercare maintenance is available annually, and we send out notification DM each year.
If you have any questions about the warranty, please click on the image above!
6. Flexible and Prompt Response
We are 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 enhancement and conduct practical training.
Since the installation methods vary depending on the shape and slope of the roof, we regularly provide technical training to ensure that each staff member can handle various cases.
8. Creation of Easy-to-Understand Materials and Simulations
At Kakeru Koumuten Co., Ltd., in addition to “estimates”, “layout diagrams”, and “power generation simulations”, we also provide a “solar installation guidebook” and a “financial simulation” that takes into account loan interest rates and electricity costs.
The financial simulation can be created for projected cumulative income and expenses over 20 to 30 years.
Even customers who are not familiar with solar installations will find the materials easy to understand, including important points and disadvantages!
We encourage you to obtain comparative estimates and review plans from other companies!
Roof Inspection Before Installing Solar Panels
Once solar panels are installed, they will remain on the roof for 20 to 30 years.
Confirming “whether it is okay to install them directly on the current roof” before installation 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 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 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 create a layout diagram from the drawings and the site, and you can confirm it with the power generation simulation. |
| 4. Shape of the roof and installable area | The number of panels (installation capacity) that can be placed depends on the shape and size of the roof. The number of panels that can be installed varies depending on their size, so we compare based on the total output of the roof. |
| 5. Method of securing and waterproofing details | We check whether the method involves drilling holes in the roofing material for fastening or using brackets to secure the roofing material. The fastening method varies by technique, so please confirm 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 also be an option if necessary. |
| 7. Location of equipment installation and wiring | We check the installation locations for the power conditioner and storage battery, as well as the wiring route to the distribution board. The length of the wiring also affects costs. |
Fastening Methods and Checkpoints by Roofing Material
| Roof Material | Main Fixing Method | Pre-Installation Check Points |
|---|---|---|
| Slate Roof | Varies by method (e.g., fixing brackets to the roof material and substrate with screws) | Waterproofing treatment of fixing parts, cracks or deterioration of slate, condition of the substrate. If deterioration is advanced, consider roof overlay (cover method) or replacement first. |
| Tile Roof | Fixed with brackets and methods suitable for the type of tile (even methods that do not drill holes in the tiles will fix to the substrate) | Type and condition of tiles, substrate, load-bearing capacity. Depending on the investigation results, there may be a method to replace with lightweight roofing material 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, a method that does not drill holes may be selectable. |
| 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 perform roof renovations 10 to 20 years after installation, there will be additional costs for removing and reinstalling solar panels. If the roof is deteriorating, it may be more cost-effective in the long run to renovate to a highly durable roofing material before installation.
Kakeru Koumuten Co., Ltd. specializes in roofing work and can also handle the removal and reinstallation of solar panels in-house, so please consult us according to the condition of your roof!
▶ Click here for roof renovations in Asahi Ward, Yokohama City
PotentialSubsidies and Grants
If you are introducing solar panels or storage batteries in Asahi Ward, there is a possibility that the systems of “the national government,” “Kanagawa Prefecture,” and “Yokohama City” may apply.
The following information is based on the official pages of each system as of October 6, 2026. The acceptance status may change depending on the budget, so please check the latest information before contracting or starting work.
Eligibility Conditions and Application Period for Subsidy Programs
| Program | Main Eligibility Conditions | Subsidy Amount | Application Period & Status |
|---|---|---|---|
| Yokohama City “Yokohama Green Energy Partnership Project (YGrEP)” Reiwa 8 Fiscal Year | Yokohama residents installing eligible equipment at their homes. Solar power must be newly installed, and either a storage battery, eco-cute, or electric vehicle must be installed simultaneously or already in place. | Solar power: 15,000 JPY/kW (up to 4 kW) Storage battery: 120,000 JPY per case (Cashless points and other rebates available) |
Participation and installation support applications: June 15, 2026 – December 25, 2026 (Application must be made before installation) Installation completion application: By January 22, 2027 Ends when budget limit is reached |
| Kanagawa Prefecture “Reiwa 8 Fiscal Year Kanagawa Prefecture Residential Solar Power Generation and Storage Battery Installation Subsidy” | Installation of both solar power generation and storage battery in residential properties within the prefecture. Applications must be made by the individual, and construction can begin after the grant decision. | Solar power: 70,000 JPY/kW Storage battery: 150,000 JPY 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 applications. |
| National “DR Home Storage Battery Project” (Reiwa 7 Fiscal Year Supplement) | New installation of home storage systems that can be utilized for DR (demand response) with registered products. | Calculated based on an initial effective capacity of 1 kWh at 34,500 JPY (subsidy rate within 3/10; maximum 600,000 JPY per application) | As of May 29, 2026, the budget has been reached, and applications are now closed (currently, applications cannot be made) |
| National “Mirai Eco Housing 2026 Project” (Renovation) | Storage batteries are one of the eligible facilities, but they must be combined with essential works such as insulation renovation of windows (openings) and the building structure; applications cannot be made for just the installation of storage batteries. Solar panels are not included as eligible facilities. | Storage battery: 96,000 JPY per unit | Ends when the budget limit is reached. Please check the official site for application status. |
| Yokohama City “Solar Power Generation Installation Support Grant” | Small and medium-sized enterprises and sole proprietors in Yokohama City (residential use is not eligible). There are conditions for the target person and equipment, such as being a self-consumption type facility. | Solar power + storage system: 100,000 JPY/kW (up to 5,000,000 JPY) Solar power only: 80,000 JPY/kW (up to 4,000,000 JPY) |
May 1, 2026 – October 30, 2026, 17:00 (first-come, first-served until budget limit is reached) |
| Kanagawa Prefecture “Reiwa 8 Fiscal Year Kanagawa Prefecture Self-consumption Renewable Energy Installation Subsidy” | Corporations and individuals filing blue returns（Individual residences are excluded）。Solar power must have a generation output of 10kW or more, facilities for business use, and equipment not certified under FIT or FIP, etc. | Solar power: 80,000 JPY/kW, etc. Storage system: 50,000 JPY/kWh (up to 5,000,000 JPY) |
Application closed on September 3, 2026 (when the application amount reached the budget) |
YGrEP requires “participation and introduction support application” before installation, and for Kanagawa Prefecture’s residential subsidies, it is a condition that construction begins only after receiving the “grant decision”. If you start installation or construction beforehand, you will be excluded. The prefecture’s residential subsidies are granted after a performance report and review following the completion of construction. The order of procedures varies by system, and applying does not guarantee a grant, so please confirm before contracting or starting construction.
Kakeru Koumuten Co., Ltd. will guide you on the eligibility conditions and business requirements 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 project targets those who are newly introducing registered storage systems that can be utilized for demand response (DR). In the fiscal year 2027 supplementary budget, the subsidy amount is determined based on a standard amount of 34,500 JPY per initial effective capacity of 1kWh, with a subsidy rate of up to 30% and a maximum of 600,000 JPY per application. There are conditions such as being excluded if contracted or ordered before the grant decision.
However, the fiscal year 2027 supplementary budget reached its application amount on May 29, 2026, and the public recruitment has ended (the previous fiscal year’s supplementary budget also ended public recruitment on July 2, 2025). Applications are currently not possible, so please check the official website for future public recruitment.
Additionally, there are currently no subsidies confirmed for the installation of solar panels on existing homes.
👉 Click here for the official site of the DR Home Storage Battery Project
Kanagawa Prefecture “Fiscal Year 2028 Kanagawa Prefecture Residential Solar Power Generation and Storage Battery Installation Subsidy”
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 1kW of solar power generation and 150,000 JPY per storage system.
For example, if you install a 4kW solar panel and one storage battery, the subsidy amount calculation would be 4kW × 70,000 JPY + 150,000 JPY = 430,000 JPY.
Conditions include that the storage system must be a registered product, if construction begins before the grant decision, it will be excluded, and the application must be made by the individual (proxy applications by contractors are not allowed). It is also possible to combine it with YGrEP in Yokohama City.
For the fiscal year Reiwa 8, the first application period (May 11 – June 30) and the second application period (September 7 – September 30, first-come-first-served) have been conducted, and the second period has reached its application deadline. For future recruitment, please check the official Kanagawa Prefecture page.
👉 Click here for the official Kanagawa Prefecture page
Kanagawa Prefecture “Reiwa 8 Fiscal Year Kanagawa Prefecture Subsidy for Self-Consumption Type Renewable Energy Introduction” (for businesses)
Kanagawa Prefecture is also implementing subsidies for businesses introducing “self-consumption type” facilities that use electricity generated by solar panels.
Eligible applicants are corporations or individual business owners filing blue returns, and individual residential installations are not eligible.
Conditions include solar power generation with an output of 10kW or more, supplying electricity to business facilities within the prefecture, and being equipment that does not receive FIT/FIP certification.
The subsidy amount is 80,000 yen per kW for solar power generation and 50,000 yen per kWh for the accompanying storage system (with a maximum of 5 million yen).
As the application amount reached the budget amount for the fiscal year Reiwa 8, applications were closed on September 3, 2026.
Businesses considering the installation of solar panels on commercial buildings in Asahi Ward should check the official Kanagawa Prefecture page for the next recruitment.
👉 Click here for details
Yokohama City “Subsidy for Solar Power Generation Introduction” (for businesses)
Yokohama City is implementing a system to subsidize part of the introduction costs for small and medium-sized enterprises and individual business owners within the city for solar power generation facilities and other installations.
Residential solar power generation is not eligible, and for households, the YGrEP below will be the contact point. Businesses installing solar panels in stores, offices, factories, etc., in Asahi Ward may have the possibility to utilize this, but simply running a business from home does not guarantee eligibility. It is necessary to confirm the requirements for small and medium-sized enterprises and individual business owners, as well as the condition of being self-consumption type equipment (equipment aimed at selling electricity is not eligible).
The subsidy amount is 100,000 yen per kW when introducing solar power generation and storage systems simultaneously (maximum of 5 million yen), and 80,000 yen per kW for solar power generation only (maximum of 4 million yen).
The application period for the fiscal year Reiwa 8 is from May 1, 2026, to October 30, 2026, at 5 PM, on a first-come-first-served basis until the budget limit is reached. Installation of equipment and commencement of construction must occur after the grant decision date.
For detailed conditions and application methods, please check the official website of Yokohama City.
👉 Click here for the official Yokohama City page
Yokohama City “Reiwa 8 Year Yokohama Green Energy Partnership Project (YGrEP)”
Yokohama Green Energy Partnership (YGrEP) is a project aimed at realizing a decarbonized society.
In Yokohama City, households that participate in YGrEP and install eligible equipment (refer to the eligible equipment below) will receive cashless point rewards. Residents of Asahi Ward are also eligible.
◎Eligible Equipment and Reward Amounts◎
● Solar Power Generation Equipment (new installation): 15,000 JPY/kW (up to 4kW)
* It is a condition to install either a storage battery, eco-cute, or electric vehicle simultaneously or to have already installed one.
● Storage Battery: 120,000 JPY per unit
● Eco-Cute: 20,000 JPY per unit
● Electric Vehicle / Plug-in Hybrid Vehicle (set with solar power generation equipment): 100,000 JPY per unit
* It is a condition to install the storage battery, eco-cute, or electric vehicle (set) simultaneously with the solar power generation equipment or to have already installed one.
● Electric Vehicle alone (without solar power generation equipment): 50,000 JPY per unit
● Fuel Cell (Enefarm): 30,000 JPY per unit
● Solar Heat Utilization System: 50,000 JPY per unit
● V2H Charging and Discharging Equipment: 100,000 JPY per unit
For example, if you install a 4kW solar panel and a storage battery at the same time, the calculation for the reward amount will be 60,000 JPY for solar power + 120,000 JPY for storage battery = a total of 180,000 JPY.
The application process is “Participation and Installation Support Application (before installation) → Equipment Installation → Completion Application”, and equipment installed before the installation support application is not eligible. The participation and installation support application for Reiwa 8 Year will be from June 15, 2026, to December 25, 2026, and the completion application will be until January 22, 2027, and will end once the budget limit is reached.
If you sell electricity, it must only be the surplus that cannot be used at home, and submission of monitoring data such as power generation amounts approximately once a year is also a condition. Note that only V2H charging and discharging equipment will be eligible for point rewards for businesses.
For information on application methods, combining with national and Kanagawa Prefecture subsidy projects, point rewards, and more, please check the special site here for details and inquiries.
Solar Panel Installation & Battery Installation Price List
⇧Service Menu | For Costs Related to Solar Panel Installation & Battery Installation, Click Here
⇧Service Menu | For Costs Related to Solar Panel Removal & Water Heater Removal, Click Here
Breakdown of Installation Capacity, Equipment, and Construction Costs
The costs for solar panels and batteries should be checked by separating them into “Equipment Costs (Device Costs)” and “Construction Costs.”
Even for the same “Complete Solar Panel Installation,” the amount can vary significantly depending on the installation capacity, equipment grade, and roof condition.
Considerations for Installation Capacity (kW) and Battery Capacity (kWh)
The installation capacity of solar panels is determined by “the output of one panel (W) × number of panels”, with the unit being kW (kilowatts). The battery is compared in terms of the amount of electricity it can store, represented in kWh (kilowatt-hours).
The amount of kW that can be placed on the roof varies for each house based on the shape, orientation, and size of the roof. At Kakeru Koumuten Co., Ltd., we create a layout diagram from the blueprints and on-site survey to present the installation capacity.
On our pricing page, we list solar panels as approximately 800,000 yen to 1,200,000 yen for 3 to 5 kW, and 1,200,000 yen to 1,900,000 yen for 6 to 10 kW. (These are just approximate amounts and may vary based on the length of wiring, scaffolding area, existing roofing materials, and panel layout.)
▶ Installation Menu | Costs for Solar Panel Installation and Battery Installation
Items to Check in the Estimate (Cost Confirmation)
When comparing estimates, it is common to compare different capacities and equipment. Please check if the following items are clearly stated in each company’s estimate!
| 1. Solar Panels | Manufacturer, model number, output of one panel (W), number of panels, total installation capacity (kW) are specified. |
| 2. Power Conditioner | Manufacturer, model number, capacity, number of units, installation location (indoor/outdoor). Also confirm if it is a type that controls in conjunction with the battery. |
| 3. Battery | Manufacturer, model number, capacity (kWh), range usable during a power outage (entire house or specific circuits), installation location. |
| 4. Mounting Frame and Hardware | Name of the hardware suitable for the roofing material and the method of securing it (whether it involves drilling holes or using clamps). |
| 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 included for applications to the power company, certification for selling electricity (FIT), and subsidy applications. |
| 8. Scaffolding | Scope and quantity of scaffolding. If it is simultaneous with roof work or exterior painting, check that the same scope and quantity are not counted twice. |
| 9. Removal and Disposal | Whether the removal of existing solar thermal water heaters or old panels and disposal costs for waste materials are included. |
| 10. Tax Classification and Warranty | Whether the price is tax-inclusive or tax-exclusive, conditions under which additional costs may arise, details and duration of manufacturer and workmanship warranties. |
If the capacities differ, the amounts and power generation will also change. Kakeru Koumuten Co., Ltd. welcome comparisons, so if you bring estimates from other companies, we can explain the differences item by item!
Self-Estimate and Profit Simulation for Solar Power Generation
With the simulator above,
you can obtain an estimated quote and income simulation for up to 30 years!
If you know the total installation capacity of solar panels on the roof and the capacity of the storage battery, you can get an estimated quote and income simulation!
*The simulation results are estimates. Actual income may vary based on assumptions such as electricity rates, self-consumption ratios, selling prices, and costs for equipment inspection and 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 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 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 estimates 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, so we explained it to the customer along with the estimate!
How to Choose a Solar Panel Installation Contractor in Asahi Ward, Yokohama
There are many solar panel installation contractors that serve Asahi Ward, Yokohama City, and you may be unsure which contractor to choose.
Therefore,when requesting solar panel installation or battery storage installation work, be sure to check the following four points.
● Have extensive knowledge not only about solar panels but also about roofs
● Confirm the presence of warranties and aftercare maintenance
● Obtain estimates from multiple contractors (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 contractor.
Have knowledge not only about solar panels but also about roofs
Defective installation of solar panels can sometimes 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 renovations for removal and reinstallation within a few years
・Misjudgment of the type of waterproofing led to 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 unforeseen troubles.
▶ Go to “Roof Verification Before Installing Solar Panels” in this article
Confirm the presence of warranties and aftercare maintenance
When choosing a solar installation contractor, be sure to check for warranties. It is important to confirm not only the duration of the warranty but also the scope, exclusions, and cost conditions.
While solar panels and battery storage units come with manufacturer warranties, also check for the presence of workmanship warranties in case leaks occur after installation!
For contractors that offer workmanship warranties, if leaks occur after installation, they may be able to respond under the warranty, provided it is within the warranty period and conditions.
Additionally, some contractors offer after-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 might not notice them yourself.
By conducting inspections during after-sales maintenance, you can easily detect issues early and prevent major repairs or breakdowns!
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 annual DM!
Please check the DM, and if you wish, we will visit 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 services from your desired contractor at a lower price, we recommend obtaining estimates from multiple contractors.
When comparing estimates, please check the following:
“Check the items in the estimate”
“Type of solar panel”
“Warranties and after-sales services”
Make sure to compare these details carefully! If the quality of the 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 and Equipment/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 the Kanagawa Prefecture housing subsidy, where applications cannot be submitted by the contractor and must be done by the individual, it is reassuring to have a contractor that supports the preparation of necessary documents and the flow of procedures.
Make sure to complete the procedures specified for each system (for the prefectural housing subsidy, this means obtaining the grant decision) before proceeding with the construction!
For the prefectural housing subsidy, after the construction is completed, a performance report must be submitted, and the grant will be provided after review! (The flow of procedures varies by system)
▶ To “Subsidies and Grants That May Be Applicable in Asahi Ward” within this Article
Benefits of Installing Solar Power Systems
The benefits of installing solar panels are summarized in the following 5 points!
Benefit 1: Economic Advantage
The biggest advantage of installing solar panels is the economic benefit!
While the selling price of electricity has decreased compared to 10 years ago, you can benefit by reducing the amount of electricity you purchase from the utility by consuming the electricity you generate!
As electricity costs rise, the ability to cover your consumption with solar power becomes increasingly 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 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 fiscal year 2026. After the 5th year, it is generally more advantageous to use the electricity at home (self-consumption), making the combination with storage batteries a viable option.
👉 Ministry of Economy, Trade and Industry | For purchase prices and periods, click here
Benefit 2: Subsidies Can Be Utilized!
The conditions and amounts of subsidies vary by prefecture and municipality, but if you meet the criteria, you may be able to utilize subsidies!
The reduction in your actual burden due to subsidies is a significant advantage!
In Asahi Ward, you may be eligible for subsidies from Yokohama City’s YGrEP or Kanagawa Prefecture.
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 (though devices like power conditioners may produce operational noise).
Benefit 4: Heat Insulation Effect Expected!!
By installing the panels on the roof or rooftop, they block direct sunlight from hitting the roof.
Especially in summer, this can help suppress the rise in roof temperature, providing expected heat insulation effects!
(Note that this does not improve the building’s insulation performance itself.)
Benefit 5 Electricity can be used even during power outages!!
If a storage battery is installed, it becomes possible to use electricity even during emergencies like power outages!
Even without a storage battery, if you have a power conditioner with autonomous operation functionality, 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 easy-to-overlook maintenance cost is for the roof where solar panels are installed.
If you perform roof renovations 10 to 20 years later, there will be costs for removing and reattaching the solar panels.
If the existing roof is deteriorated, it is reassuring to renovate it with durable roofing materials before installing solar panels!
Additionally, there will be costs for regular inspections of the equipment, repairs or replacements of the power conditioner, and updates due to the deterioration of the storage battery.
It would be reassuring to consider maintenance costs in the simulation before introducing solar panels!
Point 2 The risk of leaks increases depending on the roofing material
The fixing methods for slate roofs and tile roofs vary by construction method, but when using screws or other fasteners to secure the roofing material and substrate, waterproofing of the fixed parts becomes crucial.
In methods that involve making holes in the roof, the risk of leaks inevitably arises.
Of course, we will ensure proper waterproofing, but if you are concerned about making holes, replacing the roofing material with a metal roof and securing the solar panels using the catch method is also an option. (The catch method has compatibility conditions between the roofing material and fasteners, and it cannot be used with all metal roofs.)
Catch-type base metal fittings for horizontal metal roofs
Note 3: The roof will become heavier
Since solar panels will be installed, the roof will become heavier. After investigating the existing roof, substrate, and load capacity, 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 output of the roof
When installing solar panels on the roof, it is important to consider how much power can be generated in a limited area, and it is always better to generate more power!
The size and output of solar panels vary by 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 with the roof, there may be cases where “20 panels of 350W can be installed” and “15 panels of 400W can be installed” on the same roof due to the difference in panel size.
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 one 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.
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 values are standard figures for warranty purposes and do not indicate the actual degradation rate or power generation itself.
By considering the degradation rate in addition to the initial output, you can choose solar panels without regrets!
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.
Regarding the output warranty, some manufacturers offer a 30-year warranty while others provide a 10-year warranty, so it varies!
Since a longer warranty is 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 Asahi Ward
We have compiled frequently asked questions from customers considering the installation of solar panels and storage batteries in Asahi Ward. (Tap to open the answers)
How much does it cost to install solar panels and storage batteries in Yokohama City, Asahi Ward?
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 published on our solar panel and storage battery installation pricing page. We will create a layout diagram from the drawings and site survey and provide a free estimate!
Are there any subsidies available for solar power and storage battery installation in Asahi Ward?
As of October 6, 2026, the application period for Yokohama City’s YGrEP (15,000 yen/kW for solar power, up to 4kW; 120,000 yen per case for storage batteries) is ongoing (it will end once the budget limit is reached). The Kanagawa Prefecture subsidy (70,000 yen/kW for solar power; 150,000 yen per unit for storage batteries) is approaching the application deadline for the second period of Reiwa 8, 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 us before signing a contract.
Can I apply for subsidies after the construction is completed?
For many programs, procedures must be completed before construction. Yokohama City’s YGrEP requires a “participation and introduction support application” before installation, and the Kanagawa Prefecture subsidy requires “commencement of construction after grant decision,” meaning 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 installation method, and when using a method that secures brackets to the roofing material or substrate, waterproofing treatment for the secured areas is essential.
Kakeru Koumuten is a specialized exterior renovation company strong in roofing work, so we will check the roof condition before installation and suggest methods such as roof overlay (cover method) or replacement if deterioration is advanced.
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, the cost for removing and reinstalling solar panels will be incurred separately. If the remaining lifespan of the roof is short, it may be more cost-effective to renovate with durable roofing materials before installation.
Please consult us on how to proceed with the installation 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 of electricity will be 8.3 JPY/kWh after the fifth year, making it more advantageous to use it in your home rather than selling it.
Additionally, the subsidy in Kanagawa Prefecture requires the simultaneous introduction of solar panels and storage batteries, and Yokohama City’s YGrEP also requires a combination with storage batteries. You can compare “solar panels only” and “solar panels + storage batteries” through a financial simulation.
How many kW can be installed on my roof? Is it okay for north-facing roofs or roofs with shadows?
The capacity that can be installed varies depending on the shape, orientation, and size of the roof. At Kakeru Koumuten, we create a layout diagram from the drawings and site survey, and provide you with the installation capacity and power generation simulation.
Asahi Ward has a hilly terrain created by the Kaito River and its tributaries, with many residential areas in hilly regions, and the shadows cast by neighboring houses, trees, and elevation differences vary from house to house. You can check the expected power generation through the power generation simulation.
How long will the construction period be?
In the above construction example (solar panel 4.3 kW + storage battery), it took about 3 days. The duration may vary depending on whether roof work is done simultaneously and the shape and installation capacity of the roof.
Please note that additional time is required for applications for subsidies and power companies, so please consult us as soon as possible.
What is the current selling price (FIT)?
For residential use (under 10 kW), the selling price from certifications after October 2025 will be 24 JPY/kWh for the first 4 years, and 8.3 JPY/kWh from the 5th to the 10th year, and the same price will apply for the 2026 fiscal year.
The idea is to recover the initial costs quickly in the first 4 years and then focus on self-consumption. Kakeru Koumuten provides a financial simulation that takes into account loan interest rates and electricity prices.
Can you handle maintenance and inspections after installation?
Yes, we can. Kakeru Koumuten sends out annual after-maintenance DM 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.
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 renovate a roof that already has solar panels installed?
Yes, we can. Kakeru Koumuten can remove and reinstall solar panels ourselves, allowing us to remove the panels, perform roof overlay (cover method) or re-roofing, and then reinstall them in a consistent manner. The removed panels can be stored in our own warehouse.
For information on costs, please visit the solar panel removal and water heater removal pricing page.
If you are looking for a solar panel installation contractor in Asahi Ward, please consult Kakeru Koumuten
Our company handles a wide range of exterior renovations, including solar panels, roofing work, and exterior wall work in Asahi Ward, Yokohama City.
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 positive feedback from numerous customers.
We continue to update our annual construction performance records, and we will strive to improve quality to satisfy even more customers in the future.
Our company can perform all exterior renovations, not only roof overlay work and complete roof replacements but also partial roof repairs, exterior painting, and exterior cover installations.
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 with 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 by other companies in terms of cost, quality, and efficiency in exterior work!
We are confident, so we welcome competitive quotes!
Estimates are completely free, and if our company is found to be inferior to others, you are free to decline!
Characteristics of Asahi Ward, Yokohama City, and Points for Solar Work
Asahi Ward, Yokohama City, is an area where residential neighborhoods spread around Futamatagawa Station and Tsurugamine Station on the Sotetsu Line, and it is located in the headwaters of the Kaito River.
Kakeru Koumuten also has a material storage site in Kamikawaicho within the ward, and we respond to exterior work and solar work in Asahi Ward.
We have summarized the topography and housing conditions of Asahi Ward, and points to consider when installing solar panels and storage batteries below. (Tap to open)
View the characteristics of Asahi Ward and points for solar work
■ The hilly terrain created by the Kaito River and its tributaries requires attention to roof shadows and scaffolding
Asahi Ward is located in the western part of Yokohama City, covering an area of approximately 32.7 km2, making it the fourth largest among the 18 wards in the city. According to Yokohama City materials, it is situated in the headwaters of the Kaito River, characterized by a complex terrain of lowlands along the river and hilly areas.
Even within the same block, the orientation and height of roofs, as well as the shadows cast by neighboring houses, retaining walls, and trees, vary from house to house. At Kakeru Koumuten, we create layout diagrams based on blueprints and the actual site conditions, and we confirm them through power generation simulations. For sloped or uneven sites, our own scaffolding team plans the scaffolding to fit the site.
■ Large-scale housing complexes and single-family residential areas spread out, requiring pre-installation checks for older roofs
Asahi Ward was established in 1969, and since then, large housing complexes have been built in hilly areas such as Sakonyama and Hikarigaoka, with the occupancy of Wakabadai Housing Complex starting in 1979. According to district materials, about 90% of the urbanization area is occupied by residential areas, and many housing developments and complexes from the 1950s to 1970s are now due for renewal.
For older single-family homes, 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 help reduce future costs for removing and reinstalling solar panels.
■ Areas with abundant greenery require attention to fallen leaves and dirt
Asahi Ward has about 40% of its area designated as urbanization control zones, where nature remains around the Kaito River and hilly areas, including the “Yokohama Zoo Zoorasia.” On the other hand, roofs close to trees are prone to accumulation of fallen leaves and dirt on the panels, which can lead to a decrease in power generation. Kakeru Koumuten offers solar panel cleaning with specialized brushes, as well as rain gutter cleaning services.
■ Yokohama’s annual sunshine duration is approximately 2,018 hours
According to the Japan Meteorological Agency’s average values (1991-2020), Yokohama’s annual sunshine duration is about 2,018 hours. August has the most sunshine, while June during the rainy season has the least.
Power generation varies by season, so conducting annual power generation simulations and selecting battery capacities that match peak electricity usage times are key points.
■ Consideration for residential area rules
Asahi Ward has several building agreements, such as the Iizawa Housing District Building Agreement and Yokohama Kowa-dai Building Agreement (not all areas in the ward have the same rules). In areas with specific regulations regarding roof installations, it is necessary to check the details in advance.
Our company has a material storage site in Kamikawai-cho, Asahi Ward, and we handle exterior construction and solar work in Asahi Ward.
We are happy to assist with partial roof repairs such as roof overlay work, roof replacement, and leak repairs, as well as other repairs! Please feel free to consult us for any sudden troubles!
Service Area in Asahi Ward, Yokohama City
Kakeru Koumuten accepts requests throughout Kanagawa Prefecture and Tokyo.
List of Areas in Asahi Ward, Yokohama City
Asahi Ward, Ichizawa-cho / Asahi Ward, Imagawa-cho / Asahi Ward, Imajuku / Asahi Ward, Imajuku Higashi-cho / Asahi Ward, Imajuku Nishi-cho / Asahi Ward, Imajuku Minami-cho / Asahi Ward, Imajuku-cho / Asahi Ward, Oike-cho / Asahi Ward, Odaka-cho / Asahi Ward, Kashiwamachi / Asahi Ward, Kanegatani / Asahi Ward, Kamikawaicho / Asahi Ward, Kamishirane / Asahi Ward, Kamishirane-cho / Asahi Ward, Kawai-juku-cho / Asahi Ward, Kawai Honmachi / Asahi Ward, Kawashima-cho / Asahi Ward, Kirigasaku / Asahi Ward, Sakonyama / Asahi Ward, Sasanodai / Asahi Ward, Sachigaoka / Asahi Ward, Santanda-cho / Asahi Ward, Shikibidai / Asahi Ward, Shimokawaicho / Asahi Ward, Shirane / Asahi Ward, Shirane-cho / Asahi Ward, Zenbu-cho / Asahi Ward, Miyako-cho / Asahi Ward, Tsurugamine / Asahi Ward, Tsurugamine Honmachi / Asahi Ward, Nakao / Asahi Ward, Nakakibogaoka / Asahi Ward, Nakazawa / Asahi Ward, Nakashirane / Asahi Ward, Nishikawashima-cho / Asahi Ward, Higashi Kibogaoka / Asahi Ward, Futamatagawa / Asahi Ward, Honjuku-cho / Asahi Ward, Honmura-cho / Asahi Ward, Mankigahara / Asahi Ward, Minami Kibogaoka / Asahi Ward, Minami Honjuku-cho / Asahi Ward, Yasashicho / Asahi Ward, Wakabadai
・Trust Kakeru Koumuten for exterior wall painting in Asahi Ward, Yokohama!
・Trust Kakeru Koumuten for roof renovations in Asahi Ward, Yokohama!
・Trust Kakeru Koumuten for exterior renovations in Asahi Ward, Yokohama!
・Trust Kakeru Koumuten for leak repairs in Asahi Ward, Yokohama!
・Trust Kakeru Koumuten for waterproofing work in Asahi Ward, Yokohama!
・Kakeru Koumuten Co., Ltd. project achievements
・Kakeru Koumuten Co., Ltd. aftercare services
・Kakeru Koumuten Co., Ltd. service menu and price list
・Kakeru Koumuten Co., Ltd. staff blog and announcements
・Explaining the importance of comparative estimates and key points!
・Top 12 solar power manufacturers! Features and selection tips included!
・What are the installation costs for solar power generation? Tips for reducing costs thoroughly explained!
・What are the best locations for solar power installation? Key points for selecting installation sites included!
・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!
