If you would like to do it yourself, the cable for the floor heat to install under tile costs $198 in home depot, plus you will need the thermostat to control temp. The cheapest one is like $65. Then you will need to hire an electrician to pull electrical supply for it - that will cost under $300.
Next you’ll need to do the following:
- Remove existing flooring
- Install 1/4 inch hardie backer
- Nail the heat mat onto the backer (don’t damage the wire) and use a glue gun to install thermostat wire. Fish out heat wire and thermostat wire into wall location where you want the thermostat to be.
4 . Apply thinset mortar with a trowel directly over mat and install tile. - Grout and seal tile surface.
If you hire a contractor it will cost you around $3000.