A Solar Panel System For Your Japanese House: A Simple Guide

As the world moves towards a greener future, new Tokyo regulations effective April 2025 will mandate that all new detached houses be equipped with solar panels to meet a net zero CO2 emission goal.

If you’re planning to get a new house or are considering getting solar panels, this guide will provide you with the essential information to help you understand them. 

Here, we cover everything you need to know about solar panels in Japan and how to get them.

Why are solar panels necessary in Japan?

As the world moves towards a net zero CO2 emission goal by 2025, the Tokyo Metropolitan Government (TMG) formed The Carbon Half Plan to halve greenhouse gas emissions by 2023. Part of this initiative involves solar panels to prove renewable energy.

Do I need solar panels in Japan?

If you buy a new detached house in Tokyo after April 2025, you will need solar panels.

However, if you are on the fence about whether or not you want to get solar panels, here is a breakdown of the pros and cons of solar panels, particularly in Japan.

Akiya houses in Tokyo will most likely require solar panels as well, but it's best to see what your local government say.

Pros and cons of solar panels

Many regions, including Tokyo, offer subsidies, tax incentives, and rebate programs to help get solar panels for your property. 

Disregarding this factor, here are the pros and cons of solar panels in Japan.

Pros 

1. Environmental impact: Since solar panels harness sun power, they don’t release air pollutants such as carbon dioxide, unlike traditional methods that use natural gas and coal.

2. Reliable power supply: Solar panels with a storage battery can provide backup energy during power outages or disasters. With a solar power panel, you have greater control over your energy use throughout your house.

3. Reduced costs: Energy from solar panels will offset electricity costs over time. Additionally, you can sell your solar electricity back to the grid.

Cons

1. Weather conditions: The efficiency of solar panels depends on the amount of sunlight and solar radiation they receive, which greatly varies with the weather and geographic location. This variability can affect the consistency of power generation, particularly in regions prone to cloudy or rainy weather.

2. Initial high costs: The upfront costs of buying and installing solar panels can be a significant financial burden. It can be almost 1 million yen (6,500 dollars with the current exchange rate). After installation, it can save utility costs 7,800 yen per month or 93,600 yen per year.

3. Limitations: The roof needs the appropriate sun exposure and can support the weight of solar panels.

What type of solar panels are there in Japan?

There are two types of solar panel systems in Japan:

• Domestic Systems (under 10kW): Use the electricity that was generated and sell the excess.

• Commercial Systems (over 10kW): All generated electricity must be sold and can not be used for personal consumption.

Many houses will use the domestic system, while businesses will use the commercial solar panel system.

How do I install solar panels for my house in Japan?

Installing a solar panel is fairly simple when you have all the information. 

While the experience varies, we cover the general steps to help you in your process.

Step 1: Research local regulations and incentives

Check the local building codes and zoning laws about the rules of installing solar panels on your property.

You can go to your local government for more information. Plus, it will have information about incentives and tax breaks when installing solar panels.

Step 2: Obtain quotes and choose a contractor

There are many solar panel installation companies in Japan. Here are the most popular ones:

• QCELLS

• Canadian Solar (カナディアン・ソーラー)

• Next Energy (ネクストエナジー)

It’s best to get quotes from different companies to compare the prices and their services. 

Step 3: Financing the system

Many solar panel companies offer financing options, including loans, leases, or power purchase agreements (PPAs).

So, it’s best to calculate the long-term savings and payback period to understand the financial burden and future benefits.

Step 4: System design and installation

Common roof shapes in Japan

There are four types of roof houses in Japan: 

1. 切妻 (kiri dzuma)

2. 寄棟(yose mune)

3. 入母屋 (iri moya)

4. 片流れ屋根 (katanagare yane)

Each roof will need a unique panel design that the contractor will draw for your home’s needs.

The contractor will handle the permits from local authorities. Depending on the system's size and complexity, installation will take a few days to a couple of weeks.

Step 5: Inspection, connection, and activation

Once the installation is done, the local authorities will inspect it to ensure it complies with the electrical codes. If the system is connected to the grid, your utilities might need to install a device to measure the electricity flow in and out of your house.

Once approved, your contractor will activate the system. Now, you can start generating your electricity.

Step 6: Maintenance

Regular maintenance is needed for an efficient solar panel system, including cleaning and checking the inverters. 

Depending on the company that installed your solar panels, they offer solar panel maintenance as part of your total cost or as an additional service.

What does a solar panel system involve?

A breakdown of a solar panel system

A complete solar system installation includes:

• Solar panels (solar cell module): generate electricity when sunlight hits it

• Frame: contains the solar panels

• Power conditioner: adjusts the voltage for home use

• Power monitor: displays power status and usage

• Dedicated cables: for the solar panel systems

How much does a solar panel cost in Japan?

Three major factors affect the cost of solar panels:

1. Manufacturer: Different companies stall different amounts of kilowatts (kW) of solar panels 

2. The roof: the price increases proportionately to the number of solar panels covering the property. However, the shape, size, and material vary the overall costs of installing solar panels.

The third and final factor is subsidies. The government encourages new detached houses to install solar panels, and subsidies greatly help reduce the costs of installing solar panels. 

Based on varies information, a solar panel price in Japan ranges from 200,000 to 400,000 yen per kilowatt (kW).

Are there subsidies for installing solar panels in Japan?

The Tokyo Metropolitan Government is actively promoting the adoption of solar power generation through various incentives to support residents and builders in transitioning to a decarbonized society. 

These incentives are designed to reduce greenhouse gas emissions and increase energy efficiency across the city.

Here’s an outline of the key governmental incentives available for the installation of solar panels:

1. Subsidy expansions for zero-emission houses

To help create zero-emission houses, both national and local govements have created Japan solar panel subsidy systems to provide solar panel systems to properties, encouraging builders and homeowners to invest in solar technology.

a) National subsidies for solar panels in Japan

The Japanese government have subsidies for residents that are shifting toward solar power systems. These subsidies includes:

Eco-home childcare support project: 

This project is for young couples or families with young children who wants energy-efficient homes that will support up to to 600,000 yen for renovations and 64,000 yen for storage batteries.

DR subsidy 

this subsidy focuses on adjusting electricity supply and demand through storage batteries and provides 37,000 yen/kW for residential storage batteries, covering up to 1/3 of eligible expenses (max 600,000 yen)

DER subsidy

This subsidy helps manage solar power, EVs, air conditioners, and water heaters for homes and buildings.

ZEH subsidy

Additionally, there is a national system is called ZEH補助金 (ZEH Subsidy) , and here is a general breakdown of name and support amount:

Each project has an additional subsidy for eligible expenses. But here is an estimated amount you can expect:

• For newly built homes: up to 360,000 yen (120,000 yen/kW)

• For existing homes: up to 450,000 yen (150,000 yen /kW)

b) Local government subsidies

Local subsidies for solar panels in Japan varies throughout municipalities. Here are some main subsidies in Tokyo and it’s greater area:

1. Tokyo: Offers up to 950,000 yen for storage batteries under specific conditions, with an additional fixed subsidy of 100,000 yen for solar systems.

2. Adachi-ku, Tokyo: Covers 1/3 of eligible expenses for residential storage batteries (max 50,000 yen)

3. Saitama: has subsidies that cover half of eligible expenses for storage batteries under their Super City Project. Otherwise, covers 1/3 of expenses (max 120,000 yen).

4. Chiba City: provides 70,000 yen for residential storage batteries as a fixed-rate subsidy.

2. Tax incentives and deductions 

Significant tax reductions or complete exceptions exist for those who meet the requirements as part of Toky’s ZEH projects.

These incentives include exemptions from part or all of the taxes normally due on acquiring real estate, making the initial costs of stalling solar panels more affordable for property developers and home buyers.

Here is an overall summary of the deduction amount for energy-saving renovation involving solar panels.

3. Zero emission points

Tokyo extended its Zero Emission Points Program to encourage energy-efficient appliances. When Tokyo residents purchase energy-efficient home appliances, they receive points that can be exchanged for gift items. 

For example, switching to a refrigerator that saves a certain amount of energy can give you points worth up to 21,000 yen. 

4. Support for households without solar panel capability

The Tokyo government understands that not all buildings can install solar panels due to structural or regulatory limits.

Thus, the government is facilitating access to renewable energy at reasonable prices.

It will help lessen the financial burden for participants without solar panels through various campaigns, such as negotiated rates, contracts with renewable energy providers, or energy distribution.

5. For housing-related organizations

The Tokyo government is looking for ways to partner with housing-related organizations, such as residential apartments, to promote energy efficiency and renewable energy as part of the broader housing industry. 

It will make it feasible for Tokyo residents to install solar panels in their residential location, which is not a detached house.

Frequently asked questions

How many kW should I install in my home?

5kW is the national average for installing solar panels in a home in Japan. The amount varies depending on the region and the property's roof size. The maximum for a household is 10kW.

Do I need a storage battery with solar panels?

While not necessary, storage batteries are highly recommended. Solar panels create electricity, but they don't store it. So, having a storage battery is beneficial at night or when solar production is low.

Is solar panels actually worth it?

In the long run, yes. The Tokyo Metropolitan Environment Bureau estimates saving about 7,700 yen monthly on your electricity bill in Tokyo.

In closing

Investing in solar panels in Japan is more than a financial investment. In Tokyo, it’s a step toward sustainable living to help with international environmental goals.

With Tokyo setting a precedent, other cities will soon follow in this pursuit.