Solar PV vs solar thermal in Ireland comes down to what you want the sun to do. Solar PV panels make electricity, which you can use for anything in the house, store in a battery or export for payment. Solar thermal collectors heat water directly. SEAI makes the distinction clearly: panels that produce hot water are solar thermal or solar hot water collectors, while PV panels produce electricity (SEAI). This guide compares the two for Irish homes, including the current grant position for each. Checked 26 October 2026.
Solar PV vs solar thermal in Ireland at a glance
| Solar PV | Solar thermal | |
|---|---|---|
| What it produces | Electricity | Hot water |
| What it can power | Any electrical use, a battery, an EV, a heat pump; surplus can be exported | Domestic hot water (some systems also support space heating) |
| Typical contribution | Depends on size and usage; SEAI’s 2018 example: a 1.8kWp system could generate around 1,500kWh a year | Up to 60% of annual hot water demand in a well-installed system |
| Needs | Inverter; grid notification (NC6) | Usually a dual-coil hot water cylinder, pump and controls |
| Export payments | Yes, under the Clean Export Guarantee | No |
| SEAI grant | Up to €1,800 for panels, plus €600 for a 5kWh+ battery (max €2,400) | €1,200 (see grant status below) |
How each technology works
Solar PV
PV panels turn daylight into DC electricity, and an inverter converts it to AC for your home. Whatever you don’t use is exported to the grid, and your supplier pays for each exported kWh under the Clean Export Guarantee (CRU). Add a battery or a solar diverter and you can keep more of that energy at home.
Solar thermal
Solar thermal collectors absorb heat and pass it, through a fluid loop, to a coil in your hot water cylinder. SEAI describes two collector types: flat plate collectors, which can be mounted in-roof or on-roof, and evacuated tubes, which are lighter and mount on-roof only (SEAI). SEAI’s solar thermal guide says flat plate collectors generally produce less hot water per square metre than evacuated tubes, that systems are usually designed to meet 50–60% of annual hot water needs, and that a dual-coil cylinder is normally required (SEAI).
Grant status for each (October 2026)
Solar PV grant
SEAI’s application guide (V6.0, 12 October 2026) sets the PV grant at €700 per kWp up to 2kWp and €200 per additional kWp up to 4kWp, capped at €1,800, plus a flat €600 for a battery of 5kWh or more, for a maximum of €2,400. Homes must have been built and occupied before 2025 (SEAI). If you receive a qualifying welfare payment, the higher grant goes up to €9,000 (free solar panels in Ireland).
Does the solar water heating grant still exist?
Yes, as far as we can confirm. Energia’s August 2026 grant summary lists a separate solar thermal grant of €1,200 (Energia), and Selectra’s guide, updated 12 September 2026, lists solar water heating at €1,200 (Selectra). SEAI’s own pages say homeowners are entitled to a grant towards a solar thermal system (SEAI).
On eligibility dates, solarinfo.ie reported that from 6 October 2026 the solar thermal grant, like the PV grant, moved to homes built and occupied before 2025 (solarinfo.ie). We couldn’t confirm that on SEAI’s own solar water heating page, so check the date rule with SEAI before you apply.
VAT
Supply and installation of solar panels on private homes has been zero-rated since 1 May 2023. Revenue’s guidance defines solar panels as including photovoltaic panels, solar windows and solar walls (Revenue); it doesn’t mention solar thermal collectors, so ask your installer which VAT rate applies to a thermal quote.
Which should you choose?
A few rules of thumb, not a substitute for a survey:
- You want to cut your whole electricity bill: PV. It reduces what you buy for every appliance, not just hot water.
- You have an electric immersion and use a lot of hot water: both can help. PV with a solar diverter sends surplus electricity to the immersion; solar thermal heats the water directly.
- You have, or plan, a heat pump or EV: PV is usually the better match, because both run on electricity.
- Your hot water comes from an oil or gas boiler: solar thermal can pre-heat the cylinder and reduce boiler use in summer, but needs a compatible cylinder.
- Limited roof space: it’s often one or the other. Ask installers to show what each would deliver on your roof.
A common alternative to thermal collectors is PV with a diverter. See solar diverters for hot water in Ireland for how that works and what it costs.
Can you have both?
Yes, if the roof has space, and the two grants are separate measures. But the combination can overlap in summer, when PV with a diverter may already heat most of your water. For most homes, the extra cost of a second system is hard to justify unless hot water use is very high. An installer survey is the way to find out.
Costs: what we can say
SEAI’s solar thermal guide gives a cost of €800–€1,300 per square metre of collector (SEAI), but the guide is undated, so treat it as indicative only. For PV costs, SEAI’s grant page puts the typical cost at €1,700–€2,500 per kWp (SEAI); our cost of solar panels guide has the full breakdown. In both cases, a written quote for your home is the only reliable figure.
FAQs
Is solar PV or solar thermal better in Ireland?
For most homes, PV is more flexible: it powers everything, works with batteries, heat pumps and EVs, and earns export payments. Solar thermal only heats water but does that directly and efficiently.
Is there still a grant for solar water heating?
Yes. Energia (August 2026) and Selectra (September 2026) both list a €1,200 SEAI solar water heating grant. Check the current eligibility date with SEAI before applying.
How much hot water can solar thermal provide?
SEAI says a well-installed system can provide up to 60% of annual hot water demand, typically 50–60%.
Can solar PV heat my hot water?
Yes, with a solar diverter that sends surplus PV electricity to your immersion instead of exporting it.
Do I need a new cylinder for solar thermal?
Usually. SEAI’s solar thermal guide says a dual-coil cylinder is normally required.
Get your solar quote today
Get your solar quote today. Tell us about your home, hot water and heating, and we’ll connect you with SEAI-registered installers who can advise on PV, a diverter or other options for your roof. Or call 089 450 4544.
