Warm floors in a cold city
Few things beat stepping onto a warm bathroom floor on a January morning. Electric in-floor heating uses thin heating cables or mats set into the floor, usually under tile or stone. The floor warms up and radiates heat to your feet and the room.
In Edmonton homes it is popular in bathrooms, entries where boots and snow come in, kitchens, and basements built on a cold slab. Because it is thin and simple, it fits renovations where hydronic tubing and a boiler would be too much.
Electric floor heat is usually a comfort system for one room or area. Some well-insulated rooms can use it as the main heat source, but that needs a heat loss calculation to confirm.
It also pairs well with other systems. A home heated by a forced-air furnace or heat pump can add floor heat only in the rooms where cold floors bother people most, without changing the main heating.
How the floor is built
A typical installation under tile has several layers. The cable or mat sits on the subfloor or an uncoupling membrane, is covered by thinset or self-levelling compound, and then the tile goes on top. A floor sensor sits between two cable runs so the thermostat can read the actual floor temperature.
On a concrete basement slab, an insulating underlayment under the heating layer makes a big difference. Without it, much of the heat goes down into the cold slab instead of up into the room, and the floor takes longer to warm.
Some systems are made for floating floors, laminate or engineered wood. Those use different products with their own temperature limits. Never put a tile-rated cable under a floor it is not listed for.
Laying out the heated area
Heat goes where people stand and walk, not under things that sit on the floor. Cable should not run under the tub, toilet, vanity, cabinets or built-in furniture. Trapped heat under fixtures wastes power and can damage the cable or the fixture.
Mats are pre-spaced cable on a mesh, quick to roll out in a simple rectangle. Loose cable on fastening strips or a membrane takes longer but fits odd shapes, closets and curved walls better. Either way, the product is chosen to match the heated area, because most heating cable cannot be cut to length. The heating cable length is fixed; only the cold lead can be shortened.
Good layout also keeps cable spacing even and away from walls and drains by the distances the manufacturer specifies. A drawing of the final layout, with photos before the thinset goes down, is worth keeping. It tells a future owner or trade where not to drill.
Electrical requirements
Floor heating may be 120 V or 240 V depending on size. Each system needs:
- Ground-fault protection. Heating cables in floors require it under the Canadian Electrical Code. Most floor heat thermostats have it built in, with a test button.
- A suitable circuit, sized for the system and often dedicated, especially for larger areas.
- A thermostat rated for floor heat, using the floor sensor so the surface does not overheat.
- A proper junction or wall box for the cold lead connection, accessible at the thermostat location.
If you are adding several heated rooms, or adding floor heat along with other renovations, a load calculation will confirm your panel can carry it.
Hard-wired floor heating needs an electrical permit. In Edmonton that is issued by the City of Edmonton; elsewhere in Alberta under the Safety Codes Act.
Test, test and test again
Once a cable is buried under tile, a nick or a cut is very costly to fix. Installers measure the cable's resistance and insulation at several stages to catch damage right away.
Coordination between trades matters here. The electrician or installer lays and tests the cable, then the tile setter covers it. If those are different people, agree on who tests after tiling and who keeps the record. A cable damaged during tiling is much easier to fix before the grout is in.
Ask your installer for the test record. Many manufacturers require it for the warranty. Some installers also use a monitor that alarms during tiling if the cable is damaged by a trowel.
Before fastening anything to a heated floor, such as a new toilet flange or a door stop, check the layout drawing. A screw through the cable ends the system and can create a shock hazard.
Using and living with it
Floor heat responds slowly compared with a baseboard. Programmable floor thermostats warm the floor before you get up and turn it down while you are out. Set the floor temperature for comfort, not to heat the whole room on a cold night.
Many people run floor heat only from October to April and switch it off at the thermostat for summer. That is fine. In a basement on a slab, some prefer to keep a low setting year round to take the chill off.
Test the ground-fault function on the thermostat monthly by pressing the test button and resetting it. If it trips on its own and will not reset, leave it off and call an electrician.
Rugs and mats over a heated floor trap some heat. Thin, breathable rugs are usually fine; thick rubber-backed mats are not. Check the manufacturer's guidance. Our in-floor heating team can design, install and test a system as part of a bathroom or basement renovation.
Common questions
Can electric floor heat be my main heat?
In a small, well-insulated room it sometimes can. A heat loss calculation will tell you. In most Edmonton homes it is used for comfort alongside another heat source.
What drives the cost of floor heating?
The heated area, the floor type, whether insulating underlayment is needed, the thermostat, and how far the circuit runs from the panel. Bundling it with a renovation saves duplicate work.
Why does my floor heat thermostat keep tripping?
The built-in ground-fault protection has detected leakage, often from a damaged cable or moisture at a connection. Do not keep resetting it. Call an electrician to test the system.
Can I put floor heat under vinyl plank or carpet?
Only with products specifically listed for those floors, which have lower temperature limits. Check the cable and flooring instructions before buying.
Codes and permit rules change and every building is different. For work on your system, talk to a licensed electrician and your local permit authority.