All advice / Planning and cost
The short answer
If you are already renovating the bathroom and the floor is being stripped, underfloor heating is one of the most affordable comfort upgrades you can add. The cost is modest — typically $600 to $1,500 installed for a standard bathroom — and it runs for decades with almost no maintenance.
The time to install it is during the renovation, when the floor is open and the electrician is already on site. Adding it later means lifting tiles, which is costly and disruptive.
How it works
Electric underfloor heating uses a thin heating mat or cable laid on the screed before the tiles go on. The mat sits between the waterproofing membrane and the tile adhesive. A thermostat on the wall controls the temperature and the schedule.
The system heats the tile surface, not the air. You feel the warmth through your feet. It does not replace a room heater in cold climates, but in Sydney it takes the chill off a tile floor in the morning and makes the room noticeably more comfortable from autumn through spring.
What it costs
For a standard bathroom of 3 to 9 square metres, expect to pay $600 to $1,500 installed, including a programmable thermostat. The heating mat itself is the smaller part of the cost. The electrician's time to lay the mat, connect the thermostat and test the system is the larger part.
Running costs are low. A typical bathroom heating mat draws 150 to 300 watts — similar to a couple of light bulbs. Running it for an hour in the morning costs a few cents. Over a full winter, the total running cost for most bathrooms is less than $30.
Electric vs hydronic
Electric heating mats are the standard choice for bathroom renovations. They are thin, easy to install under tiles, and work independently of the home's heating system. They suit rooms up to about 15 square metres.
Hydronic underfloor heating circulates warm water through pipes in the floor. It is more efficient for heating whole houses but is more complex and expensive to install. It is rarely practical for a single-room bathroom renovation because it needs a boiler or heat pump, piping and a manifold.
For a bathroom renovation, electric is almost always the right choice.
Installation during a renovation
The heating mat is laid after the waterproofing membrane has been applied and cured. The electrician positions the mat according to the room layout — typically covering the floor area where you stand, avoiding the area under the toilet, vanity and any fixed cabinetry.
The thermostat sensor is embedded in the floor between the mat cables. The thermostat itself is mounted on the wall at switch height. The wiring connects to a dedicated circuit in the switchboard.
The tiles go on top of the mat using a flexible tile adhesive. The system is not switched on until the adhesive has fully cured — usually seven days after tiling.
What to consider
Underfloor heating works best under tile and stone. These materials conduct heat well and feel warm underfoot. It is less effective under vinyl or timber, which insulate rather than conduct.
The heating mat adds a small amount of height to the floor — typically 3 to 4 millimetres. In most renovations this is absorbed into the tile bed and makes no practical difference.
If the bathroom has a timber subfloor, check that the heating mat is compatible. Most electric mats are rated for use on timber and concrete substrates, but the manufacturer's instructions should be followed.
How ETR handles underfloor heating
Underfloor heating is discussed at the on-site measure. If you want it, it is included in the written scope and the electrical rough-in. The mat is laid after demolition and waterproofing, before tiling.
Every bathroom is waterproofed to AS 3740 with a compliance certificate. The underfloor heating sits on top of the membrane and does not affect the waterproofing. A free on-site measure anywhere in Sydney is the right starting point.
Frequently asked questions
How much does underfloor heating cost in a bathroom renovation?
For a standard bathroom of 3 to 9 square metres, expect $600 to $1,500 installed, including a programmable thermostat. Running costs are low — typically less than $30 for a full winter of morning use.
Can underfloor heating be added to an existing bathroom?
It can, but it means lifting the tiles and re-tiling after the mat is installed. That is expensive and disruptive. The practical time to add it is during a renovation, when the floor is already open.
Does underfloor heating work under all floor types?
It works best under tile and stone, which conduct heat well. It is less effective under vinyl or timber, which insulate rather than conduct. Most bathroom renovations use tile, so this is rarely a limitation.
Is underfloor heating safe in a wet area?
Yes. The heating mat is installed on top of the waterproofing membrane and is designed for wet-area use. It is connected to a dedicated circuit with safety switches. The system is tested before tiling and does not compromise the waterproofing.
How long does bathroom underfloor heating last?
Most electric underfloor heating systems are rated for 25 to 30 years or more. They have no moving parts and require no maintenance. The thermostat may need replacing before the mat does.