These are subsidy programs run by the Tokyo Metropolitan Government and city wards, and amounts, conditions and acceptance can change. For your own house, ask the program’s help desk (listed in each section) before you sign a contract.
For fiscal 2026, the Tokyo Metropolitan Government’s subsidy for home solar panels is ¥150,000 per kW (up to ¥450,000) for an existing house, and it can be used in any ward, city or town in Tokyo. Ward top-ups differ. Of 5 wards compared here (Setagaya, Nerima, Edogawa, Adachi and Ota), Nerima, Adachi and Ota pay something for solar panels, Nerima’s budget is expected to run out soon, and Setagaya has closed its second-half registration.
In short
- Tokyo’s solar subsidy is ¥150,000 per kW for an existing house (up to 3.75 kW, maximum ¥450,000) and ¥120,000 per kW for a new house (maximum ¥360,000). Batteries are ¥100,000 per kWh (maximum ¥1.2 million), and insulated windows and doors up to ¥2 million per home.
- For Tokyo’s 3 programs, sign a contract only after you receive the acceptance notice for your advance application. If you sign first, you are not eligible.
- Ward top-ups differ. Solar panels are subsidized in Nerima, Adachi and Ota, while Setagaya and Edogawa have no stand-alone solar subsidy for fiscal 2026.
- A ward closes applications when its budget is reached, even before the deadline. Nerima’s remaining budget was ¥4.483 million on October 29, and Setagaya closed second-half registration at its budget limit.
Checked with official pages on November 1, 2026 (Japan time). Amounts and acceptance status may change.
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1. Tokyo and 5 wards: solar, battery and insulated window subsidies at a glance
Tokyo’s subsidy can be used in any ward or city in Tokyo, and a ward’s subsidy is a top-up for people who live in that ward. The table below shows whether each program subsidizes each item and the amount. Tap a ward name to jump to its section.
| Program | Solar | Battery | Windows, insulation |
|---|---|---|---|
| Tokyo | ¥120,000 to ¥150,000 per kW | ¥100,000 per kWh | Up to ¥2 million per home for windows and doors |
| Setagaya | Not covered | Not covered | ¥15,000 per window, up to ¥200,000 in total |
| Nerima | Flat ¥80,000 | None | 1/6 of cost, up to ¥200,000 |
| Edogawa | No stand-alone subsidy | No stand-alone subsidy | No ward subsidy |
| Adachi | ¥60,000 per kW, up to ¥240,000 | Flat ¥50,000 | Closed on August 21 |
| Ota | 10% of construction cost (up to ¥200,000 in total) | Covered when added to solar | 10% of construction cost (up to ¥200,000 in total) |
When to apply and when acceptance ends differ by program.
| Program | When to apply | Acceptance ends | Status |
|---|---|---|---|
| Tokyo | Advance application before the contract | Grant applications until March 30, 2029 | Open |
| Setagaya | Advance registration after the contract | Grant applications by registered people until January 31, 2027 | Second-half registration closed |
| Nerima | After installation is finished | March 31, 2027 (until the budget runs out) | ¥4.483 million left (Oct 29) |
| Adachi | After installation is finished | Round 3: December 28; round 4: February 26, 2027 | Round 3 open (Nov 1) |
| Ota | Advance application before construction | Advance applications until January 29, 2027 | About 58% of budget used (Oct 1) |
2. Tokyo’s solar subsidy is ¥150,000 per kW for an existing house
Tokyo’s “Home Solar Power Introduction Promotion Program” pays ¥150,000 per kW (up to ¥450,000) for an existing house up to 3.75 kW, and ¥120,000 per kW (up to ¥360,000) for a new house up to 3.6 kW. In both cases the total cost of the panels and related items (eligible costs) is the upper limit.
| House | Smaller capacity | Above that |
|---|---|---|
| Existing house | Up to 3.75 kW: ¥150,000 per kW (maximum ¥450,000) | ¥120,000 per kW (under 50 kW) |
| New house | Up to 3.6 kW: ¥120,000 per kW (maximum ¥360,000) | ¥100,000 per kW (under 50 kW) |
There are add-ons when panels are mounted on a stand on a flat roof. For an existing detached house, a stand adds ¥100,000 per kW and waterproofing work ¥180,000 per kW, and for an apartment building a stand adds ¥200,000 per kW (flat roofs on new detached houses are not covered). Newly taking out defect insurance for renovation with the installation work adds ¥7,000 per contract.
It covers new, unused equipment installed on a house in Tokyo, and the electricity must be used in the home. Adding to an existing system is not covered. Applications are per electricity contract, so a two-household home with 2 contracts needs 2 advance applications.
The flow is: advance application, acceptance notice by email, contract, work and payment, then the grant application and performance report. File the grant application and report within 1 year of the advance application’s acceptance date or by March 30, 2029, whichever is earlier. The money is transferred about 1 month after the grant decision notice arrives. For advance applications from fiscal 2026, a payment certificate issued by a financial institution and similar documents are needed at the report stage. Procedures are on Cool Net Tokyo’s solar page (Japanese), and inquiries go to the Solar Support Team (03-6737-7006, weekdays 9:00 to 17:00).
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3. Tokyo’s battery subsidy is ¥100,000 per kWh, with solar or renewable power as a condition
Tokyo’s “Home Storage Battery Introduction Promotion Program” pays ¥100,000 per kWh of capacity, up to ¥1.2 million per home. The amount is capped at the cost excluding tax, and any subsidy from the national government or other local governments is deducted from the cost.
The condition is that you already have solar power or install it with the battery, or that you have a contract for a 100% renewable energy electricity plan. Joining a demand response (DR) trial with an electricity company adds ¥100,000, and installing an energy management device for the trial adds ¥50,000 per unit. The DR contract must be signed before the grant application and performance report.
Adding a unit to an existing battery is ¥60,000 per kWh (maximum ¥720,000), and requires solar power. For advance applications from October 1, 2026, only batteries registered with the Sustainable open Innovation Initiative (SII) under the national fiscal 2026 program are covered, so ask the seller whether the product is registered before you buy. Procedures are on Cool Net Tokyo’s battery page (Japanese), and inquiries go to the Battery Help Desk (03-6737-5100).
4. Tokyo’s window and door subsidy: up to ¥2 million per home, set by window size and performance
Tokyo’s “Energy-saving Renovation Promotion Program for Existing Homes” pays up to ¥2 million per home for insulated window and door renovations. In fiscal 2026 unit prices for windows and doors went up and an “extra large” window size was added. The amount is the sum of the unit prices for each window, and depends on performance (4 grades: P, S, A, B) and size.
| Work, performance | Small (0.2–1.6 m²) | Medium (1.6–2.8 m²) | Large (2.8–4.0 m²) |
|---|---|---|---|
| Inner window, P | ¥46,000 | ¥72,000 | ¥106,000 |
| Inner window, A | ¥12,000 | ¥18,000 | ¥26,000 |
| Window replacement, P | ¥109,000 | ¥163,000 | ¥220,000 |
| Window replacement, A | ¥58,000 | ¥87,000 | ¥117,000 |
“Extra large” windows of 4.0 m² or more are ¥133,000 for an inner window (P) and ¥277,000 for a window replacement (P). Door replacement is ¥78,000 to ¥220,000 per door, and for products registered in the national program as insulated windows that also help prevent crime, the limit is ¥3 million per home. The work must have a combined window and door subsidy of ¥50,000 or more.
Insulation for walls, floors and ceilings is one third of the cost (up to ¥1 million per home), and a high-insulation bathtub is ¥95,000 per home. New houses are not covered, and equipment contracts and work must come after the advance application is accepted. If you do not file the grant application within 1 year of the advance application, the advance application becomes void. See Cool Net Tokyo’s energy-saving renovation page (Japanese) for unit prices and eligible products, and call the Solar Support Team (03-6737-5300).
5. New houses: the “Tokyo Zero-Emission House” grant, with solar and battery top-ups
If you build a new house and it is certified as a “Tokyo Zero-Emission House” meeting the metropolitan insulation and energy-saving standards, you get a grant toward the construction cost. For a detached house it is ¥400,000 at level C, ¥1.6 million at level B and ¥2.4 million at level A. Solar panels on this house add ¥120,000 per kW up to 3.6 kW (¥130,000 for an all-electric home), and a battery adds ¥100,000 per kWh (maximum ¥1.2 million). Applications are accepted until March 31, 2027 (Fiscal 2026 Tokyo Zero-Emission House Promotion Program, Japanese; inquiries 03-6698-8757).
6. Setagaya: 4 kinds of work such as windows and doors, no solar or battery (second half closed)
Setagaya’s “Eco Housing Subsidy” has been narrowed from fiscal 2026 to 4 kinds of work: insulating windows, high-insulation doors, high-insulation bathtubs and high-reflectance roof work, with a total of up to ¥200,000. Solar panels and stationary batteries are not covered in fiscal 2026.
The amounts are ¥15,000 per window (one linked set of windows), ¥15,000 per door, ¥70,000 per bathtub and ¥100,000 per building for high-reflectance roof work. The roof amount was raised from ¥70,000 to ¥100,000 in the second half starting October 1 because of rising material prices. You must be an individual registered as a resident of the ward, for a building in the ward, using a contractor in the ward, and it can be combined with national and Tokyo subsidies.
The order differs from Tokyo’s: in Setagaya you sign the work contract first, then pre-register online to secure a budget slot. The second half of fiscal 2026 reached its budget limit, so second-half pre-registration has closed. People who already pre-registered file the grant application by January 31, 2027 (Fiscal 2026 Setagaya Eco Housing Subsidy special site, Japanese; phone 03-5539-3242).
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7. Nerima: flat ¥80,000 for solar, budget almost gone and closure expected
Nerima’s “Carbon Neutral Equipment Installation Subsidy” pays a flat ¥80,000 for solar power equipment and one sixth of the cost for high-insulation windows and doors (up to ¥200,000 with a ward contractor, up to ¥120,000 with an outside contractor). Batteries are not covered.
You apply after installation is finished, by mail, in person or online with all documents, and applications are accepted in order of arrival. It covers equipment whose installation was finished between April 1, 2026 and March 31, 2027, on the house where you live in the ward (at least 1 year after construction). People who have received this subsidy for the same type of equipment since fiscal 2021 are not eligible.
Acceptance stopped from September 16 to October 12 when the budget was reached, and resumed on October 13 with a ¥37 million supplementary budget in October. The remaining budget on October 29 was ¥4.483 million, and the ward says acceptance is “expected to end soon”. The status and remaining budget are updated almost every weekday on the Nerima Carbon Neutral Equipment Installation Subsidy page (Japanese; Global Warming Countermeasures, Environment Division, 03-5984-4706).
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8. Edogawa: the stand-alone solar and battery subsidy ended in fiscal 2025
Edogawa’s stand-alone subsidies for solar systems and stationary batteries ended with fiscal 2025. For fiscal 2026 there is a flat ¥20,000 for people who switch to 100% renewable electricity, with another ¥20,000 added if you install a solar system, a stationary battery or a high-efficiency water heater within 6 months before or after the switch.
As of October 23, 183 switches had been decided out of the planned 650. Acceptance ends when the planned number is reached (Edogawa decarbonization subsidy, Japanese).
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9. Adachi: ¥60,000 per kW for solar, apply after installation, with acceptance in rounds
Adachi’s “Solar Power System and Storage Battery Installation Subsidy” is ¥60,000 per kW for solar (up to ¥240,000) and a flat ¥50,000 for a battery. With a contractor in the ward, it is ¥72,000 per kW for solar (up to ¥288,000) and ¥60,000 for a battery. From fiscal 2026 solar and batteries are one subsidy, and you can apply for just one of them.
Apply within 12 months after you install and pay. For solar, you must have a contract with an electric company to sell surplus power. Replacements, a second or later addition and leases are not covered.
Acceptance is split into 4 rounds: round 3 is from October 1 to December 28, 2026, and round 4 from January 4 to February 26, 2027. Each round closes when its budget is reached, even partway through, and sometimes within days. When the ward’s page was checked on November 1, round 3 was open (Adachi solar and battery subsidy, Japanese; Environmental Policy Division 03-3880-5935). The “energy-saving renovation subsidy” for windows and similar work closed on August 21.
For a new detached house that received a ZEH or Tokyo Zero-Emission House subsidy from the national government or Tokyo, the ward adds one third of that amount (up to ¥300,000). Acceptance is until February 26, 2027.
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10. Ota: 10% of the cost through the “Housing Renovation Subsidy”, apply before the work
Ota has no solar-only subsidy, but solar panels, batteries and window insulation are among the eligible work under its “Housing Renovation Subsidy Program”. The subsidy is 10% of the construction cost, up to ¥200,000.
The cost is calculated as the lower of the sum of standard costs the ward sets for each type of work and the actual total cost excluding tax. The standard costs are ¥500,000 per kW for solar, ¥100,000 per kWh for adding a battery, and ¥147,000 per large window (1.6 m² or more) for window insulation. You must sign with one small or medium business with its head office in the ward, and the work cost must be ¥100,000 or more excluding tax.
The advance application (provisional application) is filed before work starts, with photos from before the work. Acceptance runs until January 29, 2027, and the main application is due by 17:00 on March 19, 2027. As of October 1, about 58% of the budget of about ¥116 million had been used (Ota Housing Renovation Subsidy Program, Japanese).
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11. Order of applications when you use both Tokyo and a ward
The order differs by program: Tokyo asks for an advance application before the contract, Setagaya for registration after the contract, Ota for an advance application before the work, and Nerima and Adachi for an application after installation.
- For Tokyo’s solar subsidy, any ward subsidy you receive is deducted from the cost in the calculation. Receive the ward subsidy first, then attach the notice showing the amount to Tokyo’s grant application and report.
- Some ward subsidies require a contractor in the ward (Setagaya, Ota), and some pay more with a contractor in the ward (Nerima for windows, Adachi). Check the contractor’s location when you get quotes.
- Tokyo’s solar subsidy has add-ons for stands and waterproofing on flat roofs. For an apartment building’s flat roof, a stand is ¥200,000 per kW.
- Tokyo’s fiscal 2026 budget is about ¥101.2 billion. The graph of the share of budget used per program was still shown as “in preparation” on November 1.
12. Door-to-door sales and “no real cost” pitches for solar subsidies in Tokyo
The Tokyo Metropolitan Government does not recommend any particular company, and warns about visits and calls from salespeople who claim to be metropolitan or ward staff or contractors. The Bureau of Environment advises not to sign right away even if you are told a campaign makes it a good deal, and to get quotes from several sellers. If you sign after a door-to-door sale, you may be able to cancel under the cooling-off system for a certain period (Tokyo Bureau of Environment: common problems and how to prevent them, Japanese).
The Tokyo Environmental Public Service Corporation, which handles the metropolitan subsidies, says that sales pitches such as “you will get a refund from the company later” or “you can install with no real cost” may lead to improper applications. It has also taken measures such as excluding for a set period the procedure agents and contractors who applied with a contract higher than the real one, and updated the list on October 9 (Measures against procedure agents, Japanese). If a discount or cashback is planned, that amount is removed from the eligible cost in the application.
Fake sites posing as the metropolitan subsidy have also been found. The metropolitan subsidy pages have addresses starting with “https://www.tokyo-co2down.jp/” (Tokyo Bureau of Environment warning, Japanese). Adachi and Nerima also say their staff or contractors do not visit to explain subsidies.
Common questions
Can I receive both Tokyo’s and my ward’s subsidy?
Setagaya says its subsidy can be combined with national and Tokyo subsidies. For Tokyo’s solar and battery subsidies, the amount is calculated after deducting what you received from the ward, so the total never exceeds the cost. For other wards too, check with each office before you apply.
Can I still use Tokyo’s subsidy if I have already signed a contract?
For Tokyo’s solar, battery and insulated window programs, a contract signed before the advance application’s acceptance date is not eligible. The exception is a contract signed between April 1 and June 30, 2026: if it meets the grant requirements you can make it eligible by filing an advance application by March 31, 2027.
Where can I see whether budget remains?
Nerima publishes the remaining budget, Setagaya the acceptance status, Adachi a list of acceptance status and Ota the share of the budget used, each on the ward’s page. Tokyo plans to post a graph of the share of budget used per program on its program summary page (Japanese).
Sources
14 pages we checked
- Cool Net Tokyo’s solar page
- Cool Net Tokyo’s battery page
- Cool Net Tokyo’s energy-saving renovation page
- Fiscal 2026 Tokyo Zero-Emission House Promotion Program
- Fiscal 2026 Setagaya Eco Housing Subsidy special site
- Nerima Carbon Neutral Equipment Installation Subsidy page
- Edogawa decarbonization subsidy
- Adachi solar and battery subsidy
- Ota Housing Renovation Subsidy Program
- Tokyo Bureau of Environment: common problems and how to prevent them
- Measures against procedure agents
- Tokyo Bureau of Environment warning
- program summary page
- Japanese version of this page (日本語版)
Checked with official pages on November 1, 2026 (Japan time).
