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Old 01-11-2009, 11:54 AM   #1
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What is "Aux HT"?


Hello,

This month my electric bill was about 3x what it normally is and I'm trying to figure out what's going on. My Honeywell digital thermostat is saying "AUX HT" and I'm not sure what auxillary heat means...whether it's bad or not...and if it's bad, what I need to do to fix it.

Any help is much appreciated! Thanks!

for what it's worth, the thermostat has always blinked "FILTER" even after changing it.

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Old 01-11-2009, 12:10 PM   #2
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What is "Aux HT"?


Aux heat means your electric heating strips are on in the air handler.

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Old 01-11-2009, 12:10 PM   #3
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What is "Aux HT"?


You Probly operate a heat pump durring the heating seasion (your outdoor A/C unit). And eather it has failed and need service or you may have accedently switched your thermostat to emergency heat.
What it is telling you is you backup resistance heat is running. The heat pump is much more efficient than the resistance heat.
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Old 01-11-2009, 12:14 PM   #4
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What is "Aux HT"?


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Originally Posted by JohnH1 View Post
You Probly operate a heat pump durring the heating seasion (your outdoor A/C unit). And eather it has failed and need service or you may have accedently switched your thermostat to emergency heat.
What it is telling you is you backup resistance heat is running. The heat pump is much more efficient than the resistance heat.
I'm not 100% sure it's abnormal, but I do feel like the outdoor A/C unit has been coming on more frequently and not sounding like it normally sounds. I feel like a fan usually spins up, but instead, it's just "turning on" and not spinning.
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Old 01-11-2009, 12:18 PM   #5
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What is "Aux HT"?


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The heat pump is much more efficient than the resistance heat.

Not when the outdoor temp drops below 35, most heat pumps have outdoor temp sensor that does not allow them to run when temps are near freezing, and on a call for heat the aux heat will kick on instead.
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Old 01-11-2009, 12:20 PM   #6
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What is "Aux HT"?


That can happen durring defrost you will normally see steam coming from the a/c. But durring normal heating operaton the fan should spin. Also resistance heat will come on if the heat pump cannot keep up alone. Like if it is really cold out.
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Old 01-11-2009, 12:21 PM   #7
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What is "Aux HT"?


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Originally Posted by liberty79 View Post
I'm not 100% sure it's abnormal, but I do feel like the outdoor A/C unit has been coming on more frequently and not sounding like it normally sounds. I feel like a fan usually spins up, but instead, it's just "turning on" and not spinning.

You could have a unit thats low on charge or just going though a defrost cycle, you should call someone to check it out.
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Old 01-11-2009, 12:24 PM   #8
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What is "Aux HT"?


It's been in the 30's here in Maryland most of this month.

Hmmm...if that's normal, maybe that's not the reason for my extremely high electric bill
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Old 01-11-2009, 12:24 PM   #9
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What is "Aux HT"?


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Originally Posted by HvacWiz View Post
Not when the outdoor temp drops below 35, most heat pumps have outdoor temp sensor that does not allow them to run when temps are near freezing, and on a call for heat the aux heat will kick on instead.

HvacWiz
You are correct. We dont know the temp were they are at. I actually run mine down to about 10 deg. But I have my system setup a little different kind of a hybrid of a hybrid. I like to experiment with my own house.

Now we do 30's
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Old 01-11-2009, 12:25 PM   #10
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What is "Aux HT"?


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You could have a unit thats low on charge or just going though a defrost cycle, you should call someone to check it out.
I'm sure it's better left to an expert, but is there anything I could try on my own to troubleshoot?
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Old 01-11-2009, 12:28 PM   #11
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What is "Aux HT"?


HvacWiz is still correct you should have the system checked you may be operating on resistance more than you should be unless your electric rates recently increased
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Old 01-11-2009, 12:38 PM   #12
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What is "Aux HT"?


thanks for the tips, gentlemen...i'll have to read up on resistance heating.

thanks!
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Old 01-11-2009, 01:10 PM   #13
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What is "Aux HT"?


Re: The 35deg cuttoff isn't that more for dual fuel were the thermol break even is so the furnace will take over. Ane even economic break even vs a gas furnace. But with resistance heat the economic break would be down around 0 or less depending upon the cost of electricity. The heat pump would normally continue to operate bringing in the electric heat only as needed with the heat pump still operating at the same time. Or am I thinking incorectly.
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Old 01-11-2009, 03:20 PM   #14
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What is "Aux HT"?


Quote:
Originally Posted by JohnH1 View Post
Re: The 35deg cuttoff isn't that more for dual fuel were the thermol break even is so the furnace will take over. Ane even economic break even vs a gas furnace. But with resistance heat the economic break would be down around 0 or less depending upon the cost of electricity. The heat pump would normally continue to operate bringing in the electric heat only as needed with the heat pump still operating at the same time. Or am I thinking incorectly.

Yes, you are correct...the breakeven point is different depending what ones alternate source is. (fuel oil, LP, NG, electric).

Based on some of my own testing/tweaking and a few posts I found here, I have my HP set to shut off around 15 degrees.

Looks like I'll get to test the system this coming week as temperatures are set to drop to 0 as a low, and a high of 12.
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Old 01-11-2009, 03:50 PM   #15
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What is "Aux HT"?


Thanks
I just wanted to make sure I wasn't think it backwards.
Glad to see I am not the only one watching over and tweaking my system. My wife thinks I am nuts. But I can't help it!
Yes everyone I have a addiction to HVAC and I am trying to get help.

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