HeatTech 18-35 sqft Electric Radiant In-Floor Heating Cable System, 120V Area Coverage: 18 sqft @ 2" spacing; 25 sqft @ 3" spacing (recommended), 35 sqft @ 4" spacing. Heating Cable Length: 100ft + cold lead (10ft) Voltage: 120V; Output: 300W (3W/ft.); Amperage: 2.5 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