HeatTech 65-135 sqft Electric Radiant In-Floor Heating Cable System, 120V Area Coverage: 65 sqft @ 2" spacing; 100 sqft @ 3" spacing (recommended), 135 sqft @ 4" spacing. Heating Cable Length: 400ft + cold lead (10ft) Voltage: 120V; Output: 1200W (3W/ft.); Amperage: 10.0 Amps Heating cable is only ~1/8" thick and will not raise the floors significantly. UL listed for USA. 25-year Manufacturer Warranty