How To Size an Electric Room Heater

Electric room heaters are an excellent way to heat a room or even an entire home.  In order to get the most out of the heater, the first thing to be aware of is the size of the heater needed and how many BTUs the heater is capable of generating so you won't under purchase for the room that you're heating.

In order to determine the size of the heater that you'll need to purchase, the first thing you'll need to understand is what a BTU is. BTU stands for British Thermal Unit; this is the unit of heat needed to heat one pound of water by one degree Fahrenheit.

As complicated as it sounds, even more factors have to be taken into consideration when sizing an electric room heater.  There is a formula that can be followed to determine the approximate size of the electric room heater needed.  The formula isn't perfect, because it does not take into consideration personal preferences for warmth or the climate in which the formula is being applied.  At any rate, the formula is a satisfactory starting point in establishing the size of an electric room heater.

Square footage times height equals the volume of the room in cubic feet.  That number is then multiplied by 4, 3 or 2 depending on how well the room is insulated with 2 being the best insulated, 3 being average and 4 being poorly insulated.

Using this formula and a typical room size of 10x10 with 8 foot ceilings with an average insulation of 3 will equal a BTU of 2400 needed to heat the room.

After calculating the total BTU, the last number in the equation of sizing an electric room heater is the watts; this will determine the wattage of the heater you will purchase.  This very simple calculation takes the watts listed on the heater and multiplies it by 3.4.  This final number should come close to the number of BTUs that are needed from the first part of the equation.  For example, a 1500 watt heater, which is a very typical size, will put out 5100 BTUs - making that a very adequate choice for the room size used in the example.

Now that the formula has been learned, being able to size an electric room heater should be a reasonably simple task.  After the number has been calculated, all that is left is purchasing the electric room heater itself; with the variety available, shopping for a new heater can be a lot of fun!