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Heat pump and heat strips on simultaneously?

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22K views 4 replies 4 participants last post by  cinergi  
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#1 ·
Hello,

I have a heat pump with electric heat strip auxiliary heat. The heat strips are located downstream of the coil. My thermostat can be configured to allow the heat pump and heat strips to run simultaneously, or to turn off the heat pump when the heat strips are running. My question is, which is the better approach? I ask because when the heat pump and heat strips are on at the same time, I can smell the heat strips (it's not a burning smell, just a "hot metal" smell); this doesn't happen when only the heat strips are running. The heat generated by the heat strips themselves is more than sufficient to meet the heating demand even in the coldest weather. I'm concerned that with the heat pump running, the already-heated air reaching the heat strips might shorten their life (i.e. cause them to burn out from overheating).

Am I just worrying for nothing?

Thanks
cinergi
 
S
#3 ·
The system is designed so that both can operate simultaneously. As long as the HP is producing some heat, it's more efficient to use the HP for whatever Btu's you can garner and allow the aux heat to be just that, auxiliary rather than primary. Electricity is inherently less energy efficient than running the HP.
 
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#4 ·
By "heat pump and heat strips to run simultaneously" do you mean they turn on at the same time? That would be wasteful.
I assume you are referring to the thermostat "normal" setting which calls for heat pump first, then the heat strips if the heat pump cannot satisfy the call. The other setting I expect is "emergency" heat. The thermostat does not signal the heat pump then, only the heat strips. It does not provide more heat or cheaper heat.
Your concern about the heat strips wearing out prematurely from the output of the heat pump is unfounded. Only if you have insufficient air flow, such as from a dirty air filter or undersized ducts, would there be a problem with the heat strips. Even then the heat package has built-in thermal limits which will open the circuit for the heaters to prevent damage.
I recommend the normal heat setting for its economy of use.
 
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#5 ·
Thanks to all! Looks like the consensus is to leave it alone :)

kdean1 - You are correct, I'm referring to the thermostat allowing the heat pump to run for 30 minutes and only if the call is not satisfied, engaging the aux heat in addition to the heat pump. The other thermostat option is to let the heat pump run for 2 hours, and if the call is not satisfied, shutting off the heat pump and running the aux heat only (until the next call for heat, when the heat pump will start again). Based on the advice given here I will leave it with the first option (heat pump + heat strips after 30 minutes).

By the way, I've got an Ecobee thermostat which enables me to graph my system's performance on my PC and see exactly when the aux heat comes on to assist the heat pump. Otherwise I probably wouldn't have noticed!

Thanks again
cinergi
 
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