I had a new waterfurnace system with a closed loop that with borehole installation -  installed a few months ago and using too much electricy for a 2,300 sq ft house - the answer below is the reply when I questioned the hvac installer about the use of aux heat.

"The loop lines can take until summer to fully make contact with the soil. As they lines seat into the ground the system will have more heat available.

 

It is not unusual for the system to use some aux. Heat when the temps are in the twenties. Remember the geo is still providing the majority of the heat when the aux heat is showing on the stat. It is only providing a small percentage of the heat from the heat strips"

Does this sound correct?

If it's vertical loops then the ground contact story doesn't make sense to me. I would have thought they'd be grouted in place and that contact won't improve with time.

It does make sense that you might be using aux heat if you are now experiencing the coldest temps of the year.

We design our systems to have a thermal balance point of about 10 degrees F, below that the aux heat supplements,. This is for Buffalo NY. We also install larger loopfields to provide more safety margin. First statement is strange since the contact is there when properly grouted. Second statement is correct if you design the system to have a balance point in the 20s. I am not sure what the weather data is for Indiana.

With a WF unit, it is my understanding that your installer should have provided you with paperwork that shows your design temperature and how many hours your system is estimated to run per year at various outdoor temperatures. This page should also show at what temperature your system will need aux heat. If you don't have this information, get it from the installer.

Are you setting back the thermostat at night or when you are at work?

I am just a homeowner.  It would be interesting and helpful to know what "too much electricity" means.  Can you give us KWhrs?  Or at least extra cost.  Also, can you tell us what the heat load of your house was calculated to be and what the tonnage of the system is?

With my WaterFurnace, I expected to run aux heat when it dropped below freezing.  As geome mentioned, WF gives you a sheet that tells you how much they estimate your geo system and aux system to run.  If you want to see my printout go to: http://geochoices.com/pre-installation_info.html and click "Pre-Installation Report (pdf)" towards the bottom.  On the 5th page of this report it tells me when geo will run and when aux will run.  Of course you must take this with a grain of salt, but so far, these estimates have been spot on for my situation.

I know that my first season with geo I freaked out a little because my electric bills went from $40-$50 per month to $100 - $250 per month during the heating season.  But then I took a step back and realized I used to spend more than $400 per month in oil alone for those months.  So, I was actually realizing a significant savings.

Isaac,

We have read through your comments regarding the use of your auxiliary heat. It is possible for a horizontal loop to take anywhere from 6-12 months to settle. As for the auxiliary heat usage, we do not have the design criteria, and are unable to determine when the auxiliary heat should be energized. This is determined by the balance point of the system, and your installing contractor would have this information.

WaterFurnace International, Inc.

When someone says "too much electricity" that is subjective and unsupported.
Can you please elaborate with KW usage vs projections provided by your installer.
Joe