What we learned from a whopping cold winter

by Susan Gillin | Mar 06, 2017
Unseasonably (some say, unreasonably) cold weather in December, January and February resulted in higher electric bills that customers are still asking us about.

One thing our energy experts noticed is that many customers could have saved significantly on their bills by not switching to e-heat -- that's "emergency" or "auxiliary" heat -- on their heat pump thermostats.  


Switching to e-heat costs you  

Switching to e-heat overrides the benefits of a heat pump. Your heat pump essentially becomes a less-efficient electric furnace when you switch to e-heat.

Staff energy advisers looked at a few bills of customers who told us they switched to e-heat this winter. In one case, a customer would have saved an estimated $150 by keeping his thermostat in standard heat pump mode this winter (see chart below, bottom - click to open in full size). In another case, staff reviewed the bill of a customer who asked about switching but did not. She saved about $260 compared to what she spent last winter when she used e-heat (see chart below).
Sunnyslope customer energy use chart

Wenatchee customer energy use chartLess wear and tear?

Customers have told us their HVAC contractors recommend making the switch to e-heat when temperatures get below freezing. The idea is to reduce wear and tear on the equipment.

We asked Tom Ross of Alpine Aire Heating and Cooling for his opinion. He said he does not recommend switching to e-heat. You can read Tom’s blog post here

We can't find anything on the Internet that recommends switching to e-heat, either. Articles from Lennox, Carrier and others say to let the heat pump do what it’s supposed to. Here's one from a dealer with offices in Pasco and Yakima:

"Emergency heat is to be used in case of an emergency. Heat pump thermostats are designed to operate the heat pump in the most efficient manner possible and still maintain a level of comfort. As the temperature drops the heat pump will reach a point when it cannot produce enough heat to maintain the thermostat set point on its own. When this happens the thermostat will sparingly bring on the supplemental heat to help maintain temperature setting and comfort.

"In our area it is not required to manual(ly) turn your thermostat from heat mode to EM heat mode, unless your outdoor heat pump is malfunctioning. In lower outside temperatures you may notice that your heat pump runs more often; this can be part of normal operation."

The choice is still up to you, but if you want to save energy – and save on your electric bill – our evidence suggests avoiding that e-heat setting.

Save on your bill and be comfortable

  • Set your thermostat between 68 and 72 degrees or lower if comfortable.
  • Use a programmable thermostat to lower your home’s heat while the family is away or sleeping. (Don’t know how to use your thermostat? Watch our quick video featuring WVC Professor and HVAC expert Greg Jourdan.)
  • If you have a heat pump, during the coldest weather, lower your thermostat by 2-3 degrees. In milder winter temperatures (40 to 50 degrees), you may be able to lower your thermostat by 4-5 degrees.
  • If you have a furnace, go 10 degrees lower than normal. See  "The Ups and Downs of Thermostats")
  • Change your heat pump/furnace filter monthly.

Find tips for keeping your home more comfortable throughout the winter on our website

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