DIY test: is heat pump causing high electric bill?

If you receive a high electric bill in the winter and if you heat your Indianapolis area home with an electric heat pump and if you notice your heat pump runs 24/7, you might presume the heat pump is the problem. The trouble is, you normally have to call your heating contractor to see if the heat pump is working properly. Well here is a do it yourself test to check the heat pump, to see if it is working properly. This test is so easy, you will find yourself checking the heat pump operation every time you pass by. It’s almost as alluring as checking wet paint!

Before we start, I suggest you read an earlier blog (follow link) where I explain that it is normal for your heat pump to run non stop in cold weather. But even though your system is supposed to run often, you should know that a heat pump compressor can fail and the outside unit will still appear that it is working since the outside fan is still running. So how do we know the heat pump is doing its thing?

From the link above, you know a heat pump is two to four times more efficient than your backup electric heat. If your heat pump compressor fails and your backup heat takes over, the heat pump fan never shuts off and 6 weeks later you get a high electric bill, three times what it should be.

Here’s how to test if your heat pump is working. The outside unit is connected to the inside furnace by two copper refrigerant lines. One is the size of your thumb, the other the size of your little finger. In the winter, when the outside unit is running, feel the larger of the two copper lines. It is probably covered by a black foam insulation, so you will need to get under this foam to feel the metal pipe. This line should be very warm to the touch. It will not burn you, but on most winter days above 20 degrees, you will want to pull your finger off pretty quick. This pipe is carrying lots of heat. The heat was absorbed from the outdoor air and is now being sent to your home.

If the line is not hot:

  • Is the outside unit running? Can you get it to run by raising the thermostat? Is your thermostat improperly set to emergency heat? If you cannot get the outdoor heat pump to run… and this is not what you want to hear… it’s broke.
  • Is the heat pump in a defrost cycle? (That’s when steam is coming off the unit.) If so, wait until it’s done and test later.
  • Do you really have a heat pump? (An air conditioner is not supposed to run in the winter.) Call Precision Comfort Systems and let’s get your electric bills cut in half with a new heat pump!

If none of the above apply and the copper line is not hot, your heat pump is probably not working. The indoor electric furnace has taken over and this is costing you two to three times what you should be paying. Call Precision Comfort Systems now and we will find out exactly what is wrong.

Repeating from my last blog (but it is very important and worth a second post):

Some nasty advice is given, even among heating contractors who do not know any better, that you should use the emergency heat setting on your thermostat and “give the heat pump a break when the weather gets cold”. Well take it from me. This switch named “em. ht.” is misnamed. It has nothing to do with getting extra heating capacity or being a special setting for a cold day. It should be named, “DOUBLE OR TRIPLE MY BILLS!” When you switch to “em. ht.”, you turn off your heat pump and now the more expensive backup furnace (toaster coils) are heating your home at two to three times the cost. Don’t do this! Allow the heat pump to run and love it. New heat pumps are very efficient and they are designed to run non stop when you need it most so your heating bill is normal. Even older heat pumps are much better than the electric furnace.

If your heat pump is too old, then its ability to move heat may be less than what it should be. Call Precision Comfort Systems, your Central Indiana heat pump specialists, to evaluate your current heat pump. We can tune it up or eventually replace it so you are getting the most from the current heat pump technology.



About Energy Man Dan


2 Responses to “DIY test: is heat pump causing high electric bill?”
  1. John says:

    Hello Dan!
    My heat pump was set up to lock out the strip heaters during a defrost cycle. Of course cold air
    comes out of the registers until the end of the defrost cycle. Normally this is not a problem when
    its above 20 degrees. When its colder out, the strip heaters come on after the defrost cycle to
    boost the temperature. Was this set up to keep costs down or is there a problem?

    • Energy Man Dan says:

      John, thanks for visiting our web site. You should have your contractor repair your defrost controls. During defrost, it is necessary for the strip heat to run to maintain your comfort. Especially in some of our extreme temperatures, there would be very little savings involved if you lock out the strip heat during defrost. You would simply be delaying the amount of strip heat you are using. The home would get so cold during the defrost cycle that the strip heat would be used for a much longer time after defrost just to catch up.

      Energy Man Dan

      John’s follow up response:
      Thanks for the advice, I programmed the thermostat to have one strip of heat (second stage) to come on during the defrost cycle and the comfort level has improved quite a bit. Some of my hvac friends have told me that contractors will lock out the strip heaters during the defrost cycle to save energy until the customer complains about the cold drafts.

      People that I know with heat pumps will turn on the emergency heat when it gets extremely cold thinking the hp is not economical to use. There are contractors that tell them to do this! I have referred these people to your website, maybe they will learn something like I did!

      Again, thanks Dan keep up your excellent website.

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