Things to consider

1. Size of the space

   The first thing you need to know is the size of the space you want to heat, in square feet. This is a very easy calculation; simply multiply the length of the room by the width of the room. So, if you have a room that’s 12 feet long by 10 feet wide, the overall size of the room is 120 square feet.

2. Insulation

   The second thing you need to consider is insulation. The better your insulation is, the less heat escapes and the fewer watts you need to actually heat the space properly. If you have an older home with very little insulation you will need a higher wattage. The average home requires a baseboard heater that provides 10 watts of power per square foot. So, going back to our 12 x 10 room, multiply the square footage of the room by 10 to calculate the required watts. 120 square feet x 10 = 1200 watts.

Effectiveness of your baseboard heater

Remember, the calculation above is not 100% accurate. You may have to adjust your wattage estimate up or down depending on the unique features of your space. The following factors can have an impact on the effectiveness of your baseboard heater:

1. Poor Insulation:

   Older homes often have drafts, leaks or lack proper insulation which will allow heat to escape. You will need to increase the wattage by roughly 25% to heat a poorly insulated space, so a 120 square foot room will require 1500 watts.

2. Full Insulation (R19 Walls/R38 Ceilings):

   Newer, energy efficient homes and homes which have been renovated with efficiency in mind are designed to keep heat from escaping. The same room in a fully insulated home will require approximately 25% less wattage to heat, or 900 watts.

3. Ceiling Height:

   If your ceilings are over eight feet high, add 25% more wattage for every extra two feet of height.

4. Old Windows:

   Old, leaky windows can also allow a lot of heat to escape from a room – especially if there are a lot of them. Choose a higher wattage unit if your windows aren’t keeping the heat where it belongs.