Electric room heaters, or space heaters, have gained popularity in recent years due to rising heating costs and clever marketing ads that claim incredible energy savings by using these heaters. The problem is that many of these heaters are not used as intended which reduces the savings or the electric circuit in the house is not properly rated which can be dangerous.

 

Proper Use

The intent of room heaters is to add extra heat for individual rooms that you wish to be at a higher temperature than other rooms in your house. For example, if you spend a larger portion of your time in the living or family room, then you may wish for the temperature to be comfortable in that room while allowing the rest of the house to be at a lower temperature to save energy. Another way to think of the intended use of these heaters is as portable zone control, allowing some rooms to be warmer.

The most common misuse of room heaters is using one or more heaters to heat the entire house, replacing a more efficient option of a gas furnace. Electric heat is more efficient at converting energy to heat than other energy sources, however, it is also more expensive. On average, electric heat will cost twice as much as natural gas. Contact us to discuss efficient heating systems to meet your needs.

Additionally, if the room heater is near the thermostat then the main furnace will not function properly. You may need to have the thermostat moved to a more suitable location if you utilize room heaters.

 

Power Consumption

Contrary to what is stated in the advertising, room heaters consume large amounts of power during use. A quick look at the label on the back or bottom of the unit will provide you with the rated power. Most heaters operate at 120 volts, 60 Hz, 1500 watts. The watts is the power consumed during use and what you are billed for by the utility company.

For information on how electrical energy is calculated, see article “How to calculate electric energy cost of common household items.”

I’m not saying that these companies are lying to you, but many of the statements are misleading. For example, one ad claims the heater consume the same or less power as a coffee pot. Good deal, right?, because coffee pots don’t use much energy. Wrong! Many coffee pots are rated at 1200 – 1500 watt, which is the same amount of power as the electric heater. However, we don’t think of a coffee pot using energy since it is generally only on for a few minutes each day; whereas the heater will be on for many hours of the day.

 

Electrical requirements

It is strongly recommend to have an electrician inspect the wiring and circuit protection in your house before buying or plugging in a room heater. The following are areas that David or James will check during an inspection.

1. Available dedicated circuit rated at 20 amps with proper size wiring and breaker (or fuse).

A 20 amp circuit may seem high but keep in mind that a single heater operating at 1500 watts has a current draw of 12.5 amps (1500watt/120volts). Wiring and breakers are sized based on current. It would seem that at 12.5 amps that the 20 amp circuit would still have 7.5 amps available. Unfortunately, that is not the case as breakers and fuses are rated at 80% capacity, which in this case is 16 amps. If any other devices are on the same circuit then overloading of the circuit is likely which will cause the breaker to trip or the fuse to blow.

2. Is the wiring the proper size throughout the entire circuit?

Sometimes different size wiring will be connected together on the same circuit and may cause a larger size breaker to be used where a smaller size is more appropriate (20amp breaker used instead of 15amp). The breaker rating should be sized based on the smallest wire size in the circuit. This is a particularly dangerous situation as the wire size for a portion of the circuit may be undersized and if the circuit amperage is too high for the wire size then the wire may become hot and cause a fire. Unfortunately, this can be difficult to detect in some installation if the wiring is not accessible.

3. Is the wiring in good condition?

Where possible to inspect, the wiring and insulation surrounding the wire will be check for possible damage or degradation.

4. Is the outlet in good condition?

The outlet body and cover plate will be inspected. If broken, then outlet or cover should be replaced. The fit of the plug into the outlet will also be check to ensure a snug fit. As cords are plugged in and unplugged many times over, the outlet socket wears out. A loose fitting outlet will cause the outlet or cord to overheat and damage the outlet and cord plug end. This is a potential fire hazard.

5. Is the outlet 3-prong?

Most heaters use a 3-prong plug which includes the ground connection to carry away harmful electricity in the event of an electrical short inside the heater. The outlet providing power to the heater must be 3-prong and should be grounded back to the service panel. If the outlet is the older 2-prong type then replacement with 3-prong type is required.

6. Do not use 2-prong adapters.

There are serious concerns with using an adapter to convert a 3-prong grounded cord to a 2-prong plugin. First, the heater will not be grounded, see item 5 above. Second, the adapters are not rated for the continuous current that the heaters use and will overheat. Best case the damage is limited to the cord or outlet, worst case is a potential fire.  Third, the two prong adapters do not hold the plug firmly into the outlet. Problems similar to a loose fitting outlet as described in item 4 are likely.

7. Check the cord plug end on used heaters to ensure the prongs and molded rubber are in good condition.

The cord end will be inspected to check for damage due to overheating or bent prongs. The length of the cord will be inspected to check for any nicks or cuts in the insulation. If damaged, then the cord should be replaced.

 

Manufacturers Warnings

Read manufacturer’s warnings and the provided owner’s manual. Additional information can typically be found on a tag on the cord.

When buying and installing an electric space heater, you should follow these general safety guidelines:

• Electric heaters should be plugged directly into the wall outlet. No extension cords or power strips.
• Do not use 2-prong outlet adapters.
• Buy a unit with a tip-over safety switch, which automatically shuts off the heater if the unit is tipped over.
• Do not route cords under carpet or rugs.
• Maintain clear distances recommended by manufacturer.

 

If you have any question or concerns regarding use of room heaters please contact us.

 

Thank You,

David McGill
James McGill

 

Article written by Tim McGill, editor @ Tree Branch Publishing.