Is solar worth it in Ireland?

Solar panels run on daylight, not direct sunshine. Here is what an Irish roof produces, what we would expect it to save, and how long it takes to pay for itself.

Yes, Ireland gets enough daylight

A well-sited Irish roof produces roughly 900 to 1,000 units of electricity a year for every kWp of panels. A unit is a kWh, the thing your bill counts, and kWp is the size of the system. We model 900 units per kWp, the lower end, so the figures we show stay on the cautious side. On an overcast day the panels keep producing, at a lower output.

What we’d expect you to save

Take a 3-bed semi with 3.5 kWp of panels on a south-facing, unshaded roof, a 10 kWh battery, and a €200-a-month electricity bill at 35c a unit. We’d expect a saving of about €92 a month, about €1,100 a year. Bigger homes that use more electricity save more, and more again with an electric car charged at home.

You are also paid for the electricity you send back to the grid, at a lower rate than the price you buy at. That is why a battery is worth more than exporting: it keeps the electricity in the house.

What about payback?

That same system costs €8,500 before the grant. The SEAI grant on the panels is €1,700, so €6,800 after it. Against a saving of about €1,100 a year, we’d expect payback in about 6.2 years. After that the system keeps producing electricity you do not have to buy.

Every one of those assumptions, the system size, the roof orientation, the usage and the tariff, is written out on our How we calculate this page, at /how-we-calculate.

When solar is worth it most

The return is strongest if you use electricity during the day, add a battery to carry the daytime production into the evening, or run larger loads like a car charger or a heat pump. The more of your own electricity you use rather than buy, the faster it pays back.