There are two types of radiant floor heating
a) electric
b) hot water

The electric version consists of mats with
embedded wires placed typically in wood framed
floors under tiles or stone.  They require
substantial amperage and as such are quite
expensive to operate.

The water-filled version is ideal for embedding
into a slab on grade.   Different finished floors (ie:
wood vs stone or tile) would require separate
zones as due to differential thermal resistances.  A
plastic pex tube is tied to rebar on approximately a
12 inch grid prior to pouring the slab.  Typical
operating temperatures are about 90 degrees,
which, in southern California can be comfortably
accomplished with a couple hundred square feet
of south-facing solar panels.  

Advantages over traditional forced air heating
includes:
  • once installed, the heating of a room can be
    accomplished almost for free
  • there are no filters to be cleaned as in a
    forced air unit
  • operation is completely silent - no air sound
    or movement of an FAU (forced air unit)