I've done some math on residential solar in Ireland, on east-west facing pitched roofs, and it looks like a 4-6KW system would be break even in 5-7 years, given

I've done some math on residential solar in Ireland, on east-west facing pitched roofs, and it looks like a 4-6KW system would be break even in 5-7 years, given the current prices (44c/KWh) and the current subsidies (~2k for a ~8k install cost all in). It's a little complicated because of time of use, and it's unclear if net metering or feed-in rates will continue. While Ireland has a good chunk of renewables, mainly wind, our electricity rates are still driven by gas import prices, so they're 2x what they were a couple years ago.