Heated floors are one of the most popular comfort upgrades in a bathroom remodel, and they suit a region where the tile is cold much of the year. The choice is between electric and hydronic systems, and between doing it now or never, since the floor is open only once.
The short answer
For a single bathroom, electric radiant mats or cables under the tile are the usual choice: they're thin, quick to install and don't need a boiler. Hydronic systems that circulate warm water through tubing make more sense for larger areas or whole-house radiant heating. Either way, the time to install is during the remodel, before the tile goes down.
Electric vs. hydronic
| Electric | Hydronic | |
|---|---|---|
| How it works | Heating cables or mats under the floor covering. | Warm water circulates through tubing under the floor. |
| Best for | One or a few rooms, such as a bathroom. | Large areas or a whole-house system. |
| Installation | Relatively simple. Thin enough for most remodels. | More involved, with a heat source, pumps and manifolds. |
| Floor height | Adds very little. | Often needs more depth. |
| Electrical | Needs a thermostat and typically a dedicated circuit. | Needs power for pumps and controls. |
How electric floor heating is installed
Plan the layout
The heating element goes where you walk, not under the tub, vanity or toilet. The installer plots the layout before ordering.
Prepare the floor
The subfloor and underlayment must be solid, flat and clean. An insulating layer under the heating element helps the floor warm faster and use less energy.
Lay the element and sensor
Mats or cables are fixed to the floor, and a temperature sensor goes in so the thermostat can read floor temperature.
Test before tile
The installer checks the electrical resistance before, during and after laying tile, so a damaged cable is found before it's buried.
Tile over it
Tile goes down in thin-set mortar, and the system stays off until the mortar has cured.
Electrical and permit considerations
Floor heating is electrical work. Most electric systems need a dedicated circuit and a thermostat, and in Kirkland, electrical circuit alterations need a permit. Washington requires a licensed electrical contractor for installing wiring as a business. Ask who will do the electrical work and who pulls the permit. See bathroom remodel permits in Kirkland.
Is it worth it?
It depends on how you value comfort. In a cool, damp climate, a warm floor on a winter morning is a daily benefit, and the incremental cost is lowest when the floor is already being rebuilt. It's a smaller benefit in a bathroom that's already warm, or if you won't use it. A programmable thermostat can limit running time. And heated floors help dry the floor after showers, which supports a moisture-resistant bathroom, along with a good exhaust fan; see bathroom ventilation in the Pacific Northwest.
For tile choices that conduct heat well, see porcelain vs. ceramic vs. stone and bathroom tile and flooring. For the overall scope of a project, see bathroom remodeling in Kirkland.