I’m replacing a baseboard heater. How do I choose the size of a wall heater to replace it?

First, find the wattage and voltage of the baseboard heater you’re replacing. You can find this information on the identification label of the heater. If the label is missing, you can determine watt by measuring the length of the baseboard (most baseboards are approximately 200 – 250 watts per foot), then use the information on the electrical panel board to determine the voltage of the heater.