Residential in-floor heat is usually either a hot water circulating system for large areas, or an electric resistance-wire system for small areas, such as your bathroom.

Electric single-room systems should be designed and purchased for your specific space. The system will include a continuous wire system -- usually pre-spaced on a mesh backer -- and a sensor and a thermostatic control. Since this resistance wire is engineered specifically for your application, it must not be cut or shortened.

Ideally, a cement board substrate is installed first. Then the spaced wire system is fastened to the cement board and a coat of thinset is applied to create a new surface flush with the top of the wire elements. When this has set up, stone or ceramic/porcelain tile is installed with thinset in the usual manner. Be sure to check system continuity before enclosing it in the floor.

Line-voltage power is generally needed at the thermostat. From the thermostat, a supply line runs into the floor system, and a line runs from an in-floor sensor to the thermostat.

Electric in-floor heat systems are available also for under wood and carpet, etc. But the most efficient, effective in-floor heat installations sandwich the heating element between cement board and tile -- both heat conductors -- creating a heat sink of the entire mass. Wood, carpet, etc. are heat insulators, so systems below these can still work, but must overcome this insulating layer.

SITK designs and sells Warmly Yours in-floor electric heat systems.