Ask the Expert: Are Space Heaters Energy Suckers?

Or Can I Keep Mine Plugged in at Work and Not Feel Guilty?

Long Vu, ERS, for Zondits

Answer: In terms of energy usage, space heaters use a similar amount of energy to heat up a space as central heating systems do. In fact, space heaters have higher efficiency since almost 100% of the fuel is converted to useful heat. However, since most space heaters used in the office are electric space heaters, they can increase the operating cost if used too much because electricity is more expensive than other fuels. For example, if you use a 1.5 kilowatt space heater for 8 hours/day, the operating cost will be $1.68/day; if you use a gas furnace to provide heating for the same space, the operating cost will be $0.82/day, which is less than half. For this reason, space heaters should only be used when there is a need for a supplemental heating source or when it is impossible or too costly to run a central heating system.

In an office building that has only one or two underheated small offices, running space heaters to warm up those spaces might be a more cost-effective and energy-efficient solution. However, if a large part of the office is not heated to the desired temperature, using central heat will be a more-cost effective solution.

There is another type of space heater that requires a lower operating cost: the combustion space heater. Combustion space heaters use natural gas or propane to produce heat. Since natural gas and propane are cheaper than electricity, combustion space heaters cost less to use than electric space heaters. However, there are risks associated with combustion space heaters as they introduce unwanted combustion products, such as nitrogen oxides and carbon monoxide, into the air. A flue gas vent must be installed with them to send these dangerous byproducts to the outside, adding to the installation cost.

To sum things up, although space heaters are not huge energy suckers, they can increase the utility bill if they are used too much. Before turning on the space heater in your office you should check the temperature in other spaces in the building. If only a few spaces are cold, use the space heater. If most spaces are underheated, then use the central heating system.

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