A heated floor goes in during this renovation or not at all
A heated floor is not a retrofit. The mat sits between the substrate and the finished floor, so putting one in later means lifting whatever you just paid to install. If you are tiling a bathroom and have ever thought about heat, this is the decision point. The cost while the floor is already open is the mat, the thermostat, usually a dedicated circuit, and the extra depth in the setting bed. Coming back to do it afterwards costs all of that plus the entire floor again. Tile is also the finish that benefits most, because it is the coldest surface underfoot and it conducts the heat you are paying for.

