I just had a 5 ton split system installed in my 2300 square foot house and I live in Michigan. I feel like I have a issue with my system and have had the installers out 2 times and they told me everything is working fine. I ust about 100 gallons of propane every 3 weeks! This seems like I am using to much! What could be wrong  and at what temp. should my aux. heat kick on? thanks for the help, Cale

Cale,
Where abouts in MI?
What was your btu load?
Why did you select split over package unit with electric aux?
All bets are off on cost calculations in mi this year, but we can still give you our impressions.
Joe

I live inbetween Grand Rapids and Lansing! I was not well informed on the split systems vs. full system and the price differance was $5000. When I purchased the system I thought the installer told me that if  I ran propane that something was wrong, of course he said that he never said that! I also chose the split system because my house is only one year old and I didn't want to waste the money spent on the propane furnace! What is the btu load? Where do I find it? My heat lost anaylist said I would spend about 1200 to 1500 a year on heating and cooling! That must not be including the propane cost! If I change my thermostat  to make it think that there is no aux. heat the geo will keep the house @ 68 in sub zero weather, is it bad for the geo to run continous? I think that that would be cheaper than burning propane!

Thanks, Cale

as a comparison, I live in Michigan too, it seems when its really cold <17 deg F the geothermal runs 100% here.

It is not bad for the geo to run continuous as long as your loop temp doesn't get too low.

What should have been done on this install is to have the coil of the heat pump installed in the return air side of the furnace. The problem with this, though, is that it MIGHT void the furnace's heat exchanger warranty. Big deal.

If it were in the return air side, as it is with any electric heat setup, then the propane would be supplemental, not auxiliary/emergency. Though there may be some expense involved, I'd recommend you have this done. If it's already setup this way, then I'm surprised you're going through so much propane, other than it being so cold...

I don't have a split system, but my geo system runs continuous when it gets around freezing and below. I knew that this would happen prior to my geothermal installation process. You can see the report that my contractor gave me (page 5 of 7 shows when aux will kick in as well as % run time). If you go to this link:

http://www.geochoices.com/pre-installation_info.html

and click on "pre-installation report" you'll see what I was told my system would run like and it's pretty much been accurate.

As far as my system goes, it appears to be just fine when it runs 100% of the time.

Thanks for the replys! good information!

another option would be to install electric strip heater in the duct. Running the electric with the heat pump is going to be cheaper than running on propane by itself.

At a glance size seems okay (assuming adequate duct work-if too small heat pump could be derated somewhat). I don't see a problem with continuous operation if you are satisfied with achieved temperature (if need be you could elect to play catch up with propane later). If it is achieving 68* when we're sub zero, then I'm impressed with the performance.
You might talk to some neighbors and see how much propane they are using. This is the coldest winter I recall in years so you are likely saving much more money than you know. This may be the only winter in 10 where it is an issue at all.
I'm not a big fan of splits with propane back-up, but some folks do insist in areas with frequent power failure. It takes a lot more generator to run a 5 ton than a furnace.
J

I thought about having propane as a backup if electricity was out then I realized if I had no electricity I would not be able
to run a propane furnace with no electricity to power the blower in it...unless I had a backup generator and then you end up
with more hurdles. anyone see a cheap and workable solution ?

There are no cheap ways to run geo with a generator, so you go with electric space heaters or a propane fireplace or both.
J