What does auxilary mean when it comes to temp control with a heat pump?

Question

After using an old gas furnace  for years, we've moved into a house with all electric appliances.  This includes a heat pump.  We hear they are very energy effecient.  When AUX light comes on, are we using more electricity or is this just a function that's normal?  The brand is American Standard and it is 3 years old.

Newtgadget www.T-C-Pro.com · Accepted Answer

The aux. light means that your means of back-up (electric, fossil fuel) has come on in order to aid the H/P reach the desired T-stat setting. 

The trick to a H/P is to only move the temperature up 2 degrees at a time. If you exceed 2 degrees, you bring on the second stage (electric, fossil fuel) and this is where it will cost you a substantial amount of money.

In regards to a h/p being very efficient..........that all depends upon where you live, climate, design, etc.

Good luck
Newt

tmkng2001 · Answer

Heat pumps are found mostly in warmer climates due to the fact they are useless below 25-35F.  When the heat pump can no longer function and is below its "balance point" (its too cold outside)  then the AUX kicks in which are electric heating coils inside the air handler.   You will notice your electric bills shoot up when this happens.

Anonymous · Answer

My guess is,  it means you are you using a backup Electric heat element inside the Furnace-    this will happen most likely when temps hit below 20o

Rox · Answer

Axillary heat is when the actual heating coils turn on.  A heat pump recirculates air in the house.  When it is too cold, the heating element will turn on and you will see the light next to axillary shine.