Wet vs electric underfloor heating: Irish cost & running comparison
Choose wet (hydronic) warm-water pipework (€65–€95/m² with screed) for whole ground floors.
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Hydronic water pipes vs electric heating mats
| Comparison factor | Wet / Hydronic (16mm or 12mm pipe) | Electric Mat / Loose Cable (150W–200W/m²) |
|---|---|---|
| Installed cost per m² | €65–€95/m² (new build with screed) / €85–€125/m² (overlay) | €45–€75/m² (mat, thermostat & REC electrical tie-in) |
| Floor height added | 0mm extra in new build; 15mm–18mm on low-profile retrofit | 3.5mm–5.5mm (sits directly inside flexible tile adhesive layer) |
| Cost per kWh of heat (2026) | 8.6c–9.8c/kWh (heat pump SCOP 3.5–4.0) or 14.4c/kWh (gas) | 34.4c/kWh (standard day rate) or 15.4c/kWh (night rate) |
| Heat-up response time | 45–90 mins in 50mm liquid screed; 20–30 mins in low-profile overlay | 15–25 mins to warm bathroom porcelain tiles underfoot |
| Best room size & use case | Whole houses, extensions, open-plan kitchens (20 m² to 250 m²+) | Bathrooms, wetrooms, en-suites & utility rooms (2 m² to 12 m²) |
| SEAI grant compatibility | Eligible for up to €2,000 under SEAI Heat Pump System Grant | No SEAI grant available for direct-acting electric floor mats |
| Lifespan in the floor | 50+ years (DIN 4726 cross-linked PE-Xa / PE-RT barrier pipe) | 20–25 years for fluoropolymer-insulated twin-conductor cable |
How electric underfloor heating mats are installed in bathrooms
An electric underfloor heating mat consists of a ultra-thin (1.8mm–3.0mm) twin-conductor fluoropolymer heating cable pre-spaced on a self-adhesive fibreglass mesh roll, typically rated at 150W/m² for standard insulated bathrooms or 200W/m² for high-loss wetrooms and conservatories.
- Thermal backer board (6mm–10mm). Over an uninsulated concrete or timber bathroom subfloor, laying a 6mm or 10mm XPS foam-core tile backer board stops downward heat loss and cuts tile warm-up time from 60 minutes to under 20 minutes.
- Sizing to net free floor area. Electric heating cables must never run beneath fixed vanity units, toilet pans, bath tubs or flat-bottomed furniture (which cause localised thermal trapping). For a 6 m² bathroom with 2.2 m² of sanitaryware, a 3.5 m² or 4 m² mat is rolled out by cutting the mesh backing (never the red heating wire) to turn 90° and 180° passes.
- Floor sensor conduit & REC certification. A flexible conduit tube containing the thermostat's NTC floor-temperature probe is chased flush between two cable runs so the probe can be slid out and replaced in future without lifting a single tile. All 230V connections via a 30mA RCD spur must be certified by a Safe Electric Registered Electrical Contractor (REC).
Why wet hydronic systems win above 15 m²
Once a floor exceeds 15 m² to 20 m² — such as a kitchen-diner extension or ground-floor renovation — running direct electric resistance heating at 34.4c/kWh becomes three to four times more expensive per winter than circulating warm water from a heat pump or condensing boiler. Even if your home currently runs on a gas or oil boiler, installing 16mm or 12mm hydronic pipework makes the floor 100% heat-pump-ready for the future.
Get your underfloor heating priced in 4 quick taps
Tell us about your floor and heat source. Your request goes to one vetted underfloor heating installer covering your county, who rings you back to discuss pipe spacing, manifold zones and screed depth before giving a written quote.
Underfloor heating installation guides & specifications
Detailed Irish engineering & cost guides covering pipe spacing, manifold balancing, 15mm retrofit overlays, 35°C heat pump commissioning and floor coverings.
More technical resources: Liquid screed for underfloor heating · All guides & calculator hub · Technical trade glossary (A–Z) · Frequently asked questions · All 26 counties covered
Wet vs electric UFH: common questions
Can you cut an electric underfloor heating mat if it is slightly too long?
You can cut the fibreglass mesh backing with scissors to turn the mat around corners and fixtures, but you must NEVER cut or shorten the heating cable itself. Cutting the resistance wire changes its ohmic resistance and destroys the mat. Always measure the net free tiled area and round down to the nearest mat size.
How much does it cost to run a 4 m² electric bathroom floor mat in Ireland?
A 4 m² mat at 150W/m² draws 0.6 kW when heating up, and cycles on and off via its thermostat for roughly 50% of the programmed window. Running it for 2 hours every morning costs roughly 20c per day (€6 per month in winter) when laid over 6mm–10mm thermal backer boards.
Can wet and electric underfloor heating be used in the same house?
Yes — many Irish homeowners install wet hydronic underfloor heating across the entire ground floor and fit a small 2 m²–4 m² electric mat on a 7-day timer in an upstairs family bathroom or en-suite so warm tiles are available year-round even when the main heating is off in summer.
Underfloor heating installation across all 26 counties
Every quote request is routed to one vetted underfloor heating installer covering your county — from Dublin, Cork, Galway and Limerick to Kildare, Meath, Wicklow, Wexford, Louth, Kerry, Clare, Waterford and Donegal. Pick your county for local housing, heating and radon figures. View full 26-county directory →
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