ThermaWire 240V 1835W Thick Floor Heating Cable offers a ten-year warranty starting on the date of purchase. covers replacement or repair up to the cable's initial cost. The dual conductor heating cable has a diameter of 7 mm or 1/4 inch. max 15 W/SF; 5.6 W/F. Size recommendations: 167–209 square feet in concrete; 155–193 square feet underwood; 133–167 square feet under tile; 122-153 square feet in cold areas.