With this cold snap the last couple of days (currently 8 F ) I am testing turning off my aux heat.  Aux heat has been coming on after 30 min 1st stage and 60 min 2nd stage.

My question is do you think it would be more efficient to run longer on 2nd stage than Aux heat coming on? 

I just turned the breaker for the Aux heat off and will see how long 2nd stage runs and if it can satisfy the t stat temp of 71 deg F.

5 ton Tranquility 27, 2500 sq ft house with 2 zones.

Scott,

The aux heat gives you 1 for 1, while the 2nd stage would be around 4 to 1 unit heat to power use. So, yes, it would be more efficient with the aux heat turned off as long as the system can keep up. Is your system open or closed loop? Where are you located?

Regards,

There is no doubt that not using aux heat will save you money and lots of it.  The question is will your house be warm with out it?

 Every house is different when it comes to the balance point of needing aux heat.

 Let us know how yours works out.

I agree that you want to avoid using the Aux heat if at all possible. Keep in mind that recovery times when you use a set back temperatures will be longer when you don't have AUX heat enabled. You may run into a problem when it's extermely cold outside where the system doesn't keep the house warm enough when AUX heat is disabled, but it's definitely at least worth trying. If worse comes to worse, you can disable the Aux heat  and enable for a few weeks when the weather guy says it's going to be really cold... Like it is now.

 

  

New Jersey now is about 12 degrees outside. Our first floor thermostat has the auxilliary heat on most of the times and the heating is running now 100%....i'm sure the bill will skyrocket this coming month

Test in progress, Aux heat is turned off and so far it is maintaining 71degF  with outside temp 10degF. 

I live 60 miles north of NYC and have a closed loop with about 2100 feet of 1 1/2" pipe.

My EWT is about 38 degF (using a meat therm wrapped and insulated).

I will let you know how system holds today and tomorrow.

Thanks for the input!

I live in New Jersey too, well South Jersey and My down strairs Geothermal unit has no trouble keeping the heat to 68 degrees and I've had the Aux heat disabled for a month. 
Even when I turn the thermostat down 3 or 4 degrees, it doesn't take more than a hour or so to get it back up to 68 when I turn it back up. 
 

Tech, I talked to my installer about this and he's not recommending me to turn off the auxilliary heat. Does your bill improves without the back up?

For the last 2 months, my bill is averaging $150 per month. Looks like it will increase this month because of this many cold days we have.

I guess I'm more particular to the economic side of geo.

He's right, the system could explode. Make sure your 10 miles outside the blast zone for safety.... NOT! Turning it off isn't going to hurt the system one way of the other and if you getting a 1 to 1 ratio compared to a 3 to 1 ratio your saving $... I don't have figures to back up my claims, but logically you can see your saving $. 

quote = "Geodean"
 Every house is different when it comes to the balance point of needing aux heat.

As Geodean says, there a temperature point where AUX heat is required reguardless how big your system is. If it got cold enough outside, even my house would require AUX heat to keep it warm, because the heat loss would exceed the Geothermal system ability to keep up with the load. Now determining what the exact point is the tricky part, but if it happens rarely, why would you want to waste $ when you don't need to?

I say try it, if it doesn't offer any benifits you can certainly turn it back on. The worst that that could happen is in a closed loop system it could draw the heat out of the ground faster than it could recover, there by giving you issues in the future. If that happens, you can turn the aux heat back on, it will use more AUX heat than normal until the loop recovers. 

I'm at the point I'll try anything to make my bills lower, hell I'm thinking of sacrificing small animals to the heat gods to see if that helps.....


 

Testing complete.  With last nights temperature drop to -10degF my system maintained 71degF upstairs zone and 68degF downstairs zone.  With these extreme temperatures I a confident my system can handle heating without Aux Heat, which I will keep off at the breaker.  It took about 4 hours for downstairs to recover to 71degF with outside temperature now 17degF.

Just a little info on my test.