Adding underfloor heating: electric versus hydronic

Electric or hydronic — how they differ

There are two families. Electric systems use heating cables or mats laid under tiles or in screed, wired to a thermostat. They're cheaper to install and ideal for single rooms like a bathroom, but more expensive to run over large areas. Hydronic systems circulate warm water through pipes set into the slab, fed by a heat pump or gas boiler. They cost more up front but are far cheaper to run across a whole home, which is why they suit big heated areas.

Floor covering matters to both — tiles and stone conduct heat best, while timber and carpet need specific systems and limit the output. The rule of thumb: electric for a single room or a retrofit into one space, hydronic for a whole house you're building or renovating, where the running-cost savings pay back the higher install over time.

How the cost works

Underfloor heating is priced per square metre installed, with system type and area the main drivers. An electric bathroom system sits at the low end, electric across living areas in the middle, and hydronic across a whole home much higher — the heat pump or boiler and zone controls are a big share of a hydronic total. The calculator on this page shows indicative bands for your area and system.

Timing is the factor that dwarfs the others. Installing while floors are already up during a renovation, or into a slab being poured on a new build, costs a fraction of retrofitting into finished rooms — which means lifting floors you've just paid to lay. If you're renovating a bathroom anyway, adding electric mats then is cheap; doing it later costs several times more.

The licensed trades involved

This isn't a job for a general handyman. Electric underfloor heating involves mains wiring and must be connected by a licensed electrician. Hydronic systems involve a licensed plumber for the pipework and heat source. Check the right licensed trade is on the job for the system you've chosen, and that the connection — not just the mat or pipe laying — is covered by their licence.

When comparing installers, ask for a running-cost estimate, not just the install price — the gap between electric and hydronic shows up on your power bill, and it's the whole reason to pay more for hydronic on a large area. Confirm the thermostat or zone controls are included, and that the system suits your chosen floor covering, since timber and carpet limit what will work.

Mistakes to avoid

Underfloor heating regrets come from choosing the wrong system for the area, missing the cheap window to install during a renovation, or comparing on install price while ignoring the running cost that separates the two systems.

• Choosing electric for a large whole-home area where hydronic runs far cheaper
• Missing the cheap window to install during a renovation, then retrofitting into finished floors
• Not confirming a licensed electrician (electric) or plumber (hydronic) is doing the connection
• Comparing on install price alone without a running-cost estimate
• Overlooking that timber and carpet limit output and need specific systems
• Forgetting to confirm the thermostat or zone controls are in the quote