HeatTech 20-40 sqft Electric Radiant In-Floor Heating Cable System, 120V Area Coverage: 20 sqft @ 2" spacing; 30 sqft @ 3" spacing (recommended), 40 sqft @ 4" spacing. Heating Cable Length: 120ft + cold lead (10ft) Voltage: 120V; Output: 360W (3W/ft.); Amperage: 3 Amps Heating cable is only ~1/8" thick and will not raise the floors significantly. UL listed for USA and comes with a 25-year Manufacturer Warranty