Over a full year, yes. On a wet Tuesday evening in January, no. The gap between those two answers is what this guide is about.
A typical Irish home uses somewhere between 3,200 and 4,200 kWh of electricity a year. A well-placed 4 to 5kWp rooftop system in Ireland produces roughly that much. So on paper the sums balance. The problem is that solar makes most of its electricity between April and September, in the middle of the day, and your house wants most of its electricity between October and March, after dark.
Running fully off-grid in Ireland means buying enough battery and backup to bridge that gap, and the cost of doing it makes no sense when a grid connection is sitting there already. What does make sense is a solar and battery setup that covers most of your usage, exports the surplus and leans on the grid only when it has to.
How Much Electricity Does an Irish Home Actually Use?
Less than most people think, and more unevenly than they expect. The CSO puts the national median residential consumption at 3,228 kWh for 2025, according to its metered electricity consumption release, while the CRU’s definition of a typical domestic customer is 4,200 kWh. Your own bill will tell you which one you’re closer to.
Those averages hide two things. A house on oil or gas heating with a hob and an immersion sits near the lower figure. Add a heat pump, an EV charger and an electric shower and you can double it, and almost all of that extra load lands in winter.
The second is the daily pattern. Usage climbs from about 5pm, peaks around dinner time and stays high until bedtime. That’s precisely when the panels have stopped for the day.
How Much Can a Rooftop System Produce in a Year?
In Ireland, a south-facing system with no shading produces somewhere around 850 to 950 kWh per kWp installed each year. It varies by county, pitch and orientation, so treat it as a guide rather than a promise.
That puts a 4.3kWp system, which is 10 panels of 430W and a common size on a three-bed semi, at roughly 3,700 to 4,000 kWh a year. A 6kWp system on a larger roof lands around 5,000 to 5,700 kWh. Against the CSO median, either one covers the household’s annual total on paper.
The catch is in the word annual. Without a battery, most homes use only 30 to 40 per cent of what their panels produce directly, because the rest is generated while nobody’s home. The surplus goes to the grid, and the evening demand gets bought back.
Why Does Timing Matter More Than Totals?
Because electricity has to be used the moment it’s made, or stored. Two gaps decide how far solar alone can get you.
Winter
A panel in Cavan on a clear June day can produce five times what the same panel manages on a short, overcast December day. Across the year, roughly three quarters of your output arrives between April and September. SPV’s own breakdown of solar panel performance in winter versus summer puts figures on this for Irish conditions, and the pattern is the same on every roof in the country.
Winter is also when the house uses the most. Longer nights, heating pumps running, the tumble dryer on. Highest demand lands in the months of lowest supply.
Night
A battery fixes the night-time gap inside a single day. A 5kWh battery, which is the size the SEAI grant now covers, holds enough to run an average home’s evening load most of the year. It does not hold enough to carry a house through a run of dark January days, because there’s nothing to refill it with.
That’s the distinction that matters. Batteries shift electricity by hours. Nothing a homeowner can afford shifts it by months.
What Would Going Fully Off-Grid Take?
A lot more than people picture. To cut the ESB cable and still have the lights on in February, a typical Irish house would need a system sized for its worst week rather than its average one. In practice that means an array two to three times bigger than the house needs in summer, a battery bank of 20 to 30kWh or more, a generator for the weeks when neither is enough, and a stricter attitude to what gets switched on and when.
The difference between the two approaches is laid out in SPV’s comparison of off-grid and grid-tied solar PV systems, and the short version is that off-grid only earns its cost where there’s no grid to connect to. A remote site with a €20,000 connection quote is one thing. A semi in Navan is another.
An off-grid house also throws away its summer surplus, because there’s no grid to sell it to. A grid-tied house gets paid for it.
What Does a Realistic Solar Home Look Like?
Grid-connected, battery-backed and sized to the house. Across the 3,000-plus homes SPV Energy has fitted, the setup that works looks like this.
- A 4 to 6kWp array, sized to the roof and the bill rather than the biggest number the roof will take.
- A 5kWh battery to cover the evening peak and capture what the panels make while you’re at work.
- A hot water diverter, so surplus heats the tank before anything is exported.
- A smart meter and a night-rate tariff, so the battery can be topped up cheaply overnight in winter.
- A registered export connection, so summer surplus earns credit instead of being wasted.
A home set up this way typically covers 60 to 80 per cent of its electricity from its own roof over a year, with the grid filling the rest. That’s an estimate and it moves with your usage, but it’s the range SPV sees again and again. The export side is explained in SPV’s post on what happens to excess solar electricity in Ireland, including how the credit lands on your bill.
The bill doesn’t go to zero. It goes to a fraction of what it was, and the house keeps the grid for the weeks when the sky doesn’t cooperate.
Which Grants Help Close the Gap?
More than there were a month ago. From 6 October 2026, SEAI’s residential solar PV grant pays up to €1,800 for homes built and occupied before 2025, which brings in a lot of houses that were previously too new to qualify. Alongside it, SEAI has introduced a €600 grant for a battery of up to 5kWh, claimable with the PV grant on a single application or separately later.
For lower-income households on certain Department of Social Protection payments, the grant rises to as much as €9,000 for a solar and battery system together. The conditions are specific, so check SEAI’s site or ask SPV, who handle the paperwork on every install. SPV’s overview of solar grants in Ireland covers the residential scheme alongside the business and farm routes, and is worth a read before you get quotes.
All of these figures are correct at the time of writing and do get revised, so confirm them at the point of application.
Running an Irish house entirely on solar is possible and almost never worth doing. Covering most of it with solar and a battery, and letting the grid handle the rest, is cheaper, more reliable and now better supported by grants than it has ever been. If you’d like to see what your own roof and your own bill add up to, request a free quote through the contact page or ring 049 489 1207, and SPV will come back to you within 24 hours.
FAQs
Can an Irish house run on solar power alone?
Over a full year, a 4 to 6kWp system can produce as much electricity as a typical home uses. It can’t deliver that electricity when the house needs it most, in winter evenings, so a grid connection or a very large battery and generator setup is still required.
How much electricity does an average Irish house use per year?
The CSO reports a national median of 3,228 kWh for 2025, and the CRU’s typical domestic customer is defined at 4,200 kWh. Homes with a heat pump, an EV or electric showers can use double that.
How much electricity do solar panels produce in Ireland?
Roughly 850 to 950 kWh per kWp installed per year for a south-facing, unshaded roof. A 4.3kWp system therefore produces around 3,700 to 4,000 kWh, with about three quarters of that arriving between April and September.
Is it worth going off-grid in Ireland?
Only where there is no grid to connect to, or the connection quote runs into tens of thousands. For an ordinary house, the oversized array, large battery bank and backup generator cost far more than the grid electricity they replace.
What size battery do I need for an Irish home?
A 5kWh battery covers the evening load of an average home for most of the year and is the size the new SEAI battery grant supports. It shifts electricity by hours within a day, so it won’t carry a house through a dark week in January.
What grants are available for solar and batteries in Ireland?
From 6 October 2026, SEAI offers up to €1,800 for solar PV on homes built and occupied before 2025, plus a €600 grant for a battery of up to 5kWh. Lower-income households on certain social protection payments may qualify for up to €9,000. Check seai.ie for current conditions.