FullCalculator

Baseboard Heater Length Calculator

Calculate Baseboard Heater Length

Size baseboard heaters for a room

Formula

Heater Length (ft) = Room Area (sq ft) x Watts per sq ft / 250 watts per foot

Frequently Asked Questions

How many watts per square foot for baseboard heat?
As a general rule, plan for 10 watts per square foot for average insulation in moderate climates. Well-insulated homes need 8 watts/sq ft, while poorly insulated homes in cold climates may need 12-15 watts/sq ft.
How many feet of baseboard heat do I need?
Standard electric baseboard heaters produce about 250 watts per linear foot. Divide your total wattage requirement by 250 to get the linear feet needed. A 150 sq ft room needs about 6 feet of heater.
Should baseboard heaters be on their own circuit?
Yes, baseboard heaters should be on dedicated 240V circuits. Each 20A circuit can safely support 3,840 watts continuously (16A at 240V, applying the 80% rule for continuous loads).

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