Here is a link for 120volt, 1200-1500 watts, looks like about 15 amps would do it.
And about $1000 worth of pad and thermostat and then to wire in a couple $$.
Looks like it wood be a good idea if your plugged in most of the time. And the times your the furnace is still there.
I have this in the S/B under tile but have fiends under wood floor, but in dry areas they need to keep a hydrater(SP) of some type going to keep the floor from drying out too much.
http://www.thermosoft.com/radiant-floor-heating-products/shop/thermofloor-120v/
LEN