Underfloor heating installation guides, calculator & specs

In 2026, supplying and installing wet (hydronic) underfloor heating in an Irish new build or extension costs €40 to €65 per m² for the pipework, manifold and room thermostats, or €65 to €95 per m² complete with 50mm pumped liquid screed. Low-profile 15mm–18mm retrofit overlay systems cost €85 to €125 per m², and electric heating mats for bathrooms cost €45 to €75 per m².

Yes. Low-profile retrofit overlay panels (15mm to 18mm total build-up) bond directly on top of your existing concrete slab or floor tiles and carry 12mm oxygen-barrier pipe in a thin fibre-reinforced levelling compound. Alternatively, if you have a sound 60mm+ sand-and-cement screed, dust-free diamond milling cuts 16mm pipe channels flush into the top of the existing slab with 0mm added floor height.

Hydronic underfloor heating paired with an air-to-water heat pump in Ireland is designed for a 35°C flow temperature (and 28°C–30°C return) at -3°C outdoor temperature. Running at 35°C instead of 50°C–55°C radiator temperatures boosts heat pump seasonal efficiency (SCOP) above 4.0 and cuts winter running costs to roughly 8.5c–9.8c per kWh of heat.

While SEAI does not grant-aid underfloor heating on a standalone fossil boiler, homeowners upgrading a pre-2021 property to an air-to-water heat pump can claim up to €14,500 under the SEAI Heat Pump System Grant (€11,500 for apartments), which includes up to €2,000 (€1,000 for apartments) specifically towards installing underfloor heating.

Wet hydronic pipework is the right choice for whole ground floors, extensions and open-plan renovations over 15 m² because its running cost on a heat pump or condensing boiler is three to four times lower than direct electricity. Electric heating mats (150W–200W/m²) are ideal for single bathrooms, en-suites and small upstairs wetrooms under 10 m² where 3.5mm–5mm thickness and low upfront installation cost matter most.

With a 50mm calcium-sulphate (anhydrite) or flowing cementitious liquid screed, you can walk on the floor after 24–48 hours and start the gentle EN 1264-4 commissioning heat-up cycle at 20°C–25°C after 7 days (compared with waiting 21–28 days on traditional hand-laid sand-and-cement screed).