Solar Panel Calculator for Japan
Rooftop solar is well established in Japan, supported by feed-in tariffs and local subsidies. This free solar calculator estimates your system size, payback and savings in yen using local rates and sun hours.
Calculate my solar payback in Japan →
Solar at a glance in Japan
Moderate sun hours are offset by high tariffs and local subsidies; self-consumption plus batteries improves returns.
| Currency | Japanese yen (JPY) |
|---|---|
| Typical electricity rate | ¥ 30 per kWh |
| Installed cost | ≈ ¥ 300 per watt |
| Peak sun hours | ≈ 3.8 hours/day |
| Export / buyback | ≈ ¥ 11 per kWh |
Indicative 2026 starting points — every figure is editable in the calculator, and results depend on your own bill, roof and installer quotes.
A typical 5 kW system in Japan
At around ¥ 300 per watt, a 5 kW rooftop system costs roughly ¥ 1,500,000 and produces about 5,409 kWh in its first year at Japan's 3.8 peak sun hours a day. Your real numbers depend on your roof, shading, panel choice and how much power you use during the day — run your own figures in the calculator to see your exact payback, net savings and ROI.
How the solar calculator works
- Your setup. Japan and Japanese yen are pre-selected, with local electricity rate, install cost and sun hours filled in. Enter your monthly bill, or size the system from your appliances.
- Your roof. Search your address or tap “use my location”, then draw your roof on the satellite map — or just type its area. We check the system fits and read local sun hours from NASA data.
- Your results. Instantly see your payback period, net savings, ROI, system size, year-1 production and lifetime CO₂ offset — compare cash vs. a loan, and download a PDF report.
Common questions — solar in Japan
How many solar panels do I need in Japan?
It depends on your electricity use, roof space and local sun hours (about 3.8 peak sun hours/day here). A 5 kW system of high-wattage panels is a common starting point for a home — enter your bill or appliances and the calculator gives your exact panel count and system size.
Does Japan have net metering?
Japan uses feed-in tariffs (FIT/FIP) rather than net metering — you're paid a set rate for exported energy for a fixed term, while self-consumption offsets retail price. The calculator models the export rate as buyback.
Are there solar subsidies or incentives in Japan?
National cash support is limited, but many prefectures and municipalities offer their own rooftop or battery subsidies. Enter any local rebate you qualify for.
How much does a solar system cost in Japan?
A typical 5 kW system is around ¥ 1,500,000 at about ¥ 300 per watt installed. The calculator prices your own size.
Work out your system size
Not sure how big a system you need? These guides work back from your monthly usage:
500 kWh/month 1,000 kWh/month 1,500 kWh/month 2,000 kWh/month 2,500 kWh/month 3,000 kWh/month
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