What Size Space Heater Do I Need?
What wattage do you actually need?
Quick Answer
The standard guideline is 10 watts per square foot with 8-foot ceilings. A 12×10-foot room (120 sq ft) needs approximately 1,200 watts. A 15×15-foot room (225 sq ft) needs about 2,250 watts — requiring two units. Poor insulation or cold climates increase the requirement by 30–50%.