Radiant floor heating warms a room from the floor up, giving even, draft-free, silent heat and famously warm floors underfoot. It's a popular upgrade in bathrooms and additions and a whole-home system in some builds.
Electric vs hydronic
Electric radiant (heating mats or cables under tile) is ideal for a single room like a bathroom — easy to install during a tile job and inexpensive to run for a small area. Hydronic radiant (warm water through tubing) is more efficient for whole-home or large areas but costs more to install and needs a boiler or water heater source.
Where it makes sense
Bathrooms and kitchens benefit most from electric mats for the comfort of warm tile. Whole-home hydronic shines in new builds and slab-on-grade homes. Retrofitting whole-home radiant into an existing house is a major project.
Flooring and controls
Radiant pairs best with tile and stone, which conduct heat well; some engineered floors are rated for it, but check the manufacturer's limits. A dedicated thermostat (often with a floor sensor) controls it, and electric systems usually need their own circuit.