Geothermal related to cooling in Michigan.

[homedad]

I'm at the planning stage of a summer/ retirement home in mid Michigan. My basic question is: Is using a ground source heat pump significantly more economical than a traditional central ac that just uses the outside to dump the heat? My current home electric bill is closing in on $400 per month in the cooling season. During the heating season my electric bill is around $160 and my natural gas is about $125. I love cold and hate sweating as you can see. Does anyone with real experience know if a geothermal system for cooling would offer a drastically better energy bill. The new property has a slightly higher electrical cost per KWH but less than 1 cent. I supplement heating with wood and am not really concerned about heat. Also considering the climate trend I believe that cooling is a bigger factor for me to consider. Thanks.

 

[ponytug]

The short answer is yes, geothermal is slightly more efficient, and should have slightly lower bills for central Michigan.

The longer answer geothermal will not lower your bill by much, and may not lower the cost at all in your lifetime.
Two factors are at play;
1) geothermal systems cost much more to install, either because of the wells, or the trenches to install pipes. They work best when the groundwater level is close to the surface and the pipes can be set in wet soil from the service. They also have to pump water around the loops, or up and down the wells for a standing water friction loss.
2) Air cooled heat pumps used not to function well in extreme cold, but that is no longer the case. Advances in heat pump design have enabled air cooled heat pumps that function in very cold -5F to -20F.

However, for both types, you will be best served by designing a home with super insulation. E.g. 12-16" walls, with offset studs or densified fiberglass outside of the studs, triple pane windows, air heat exchanger, R60 in the attic, double door entryways, and skipping the Viking gas range with its monster exhaust fan.

There are a number of good threads here on heat pumps.

All the best,

Peter

 

[buckeyefarmer]

only if you can do pump and dump geothermal and not use loops, or you have a nice big lake to bury the loops in. Todays heat pumps getting much more efficient. I have 2 geo systems in my house. it has saved me because I installed it myself, and I was burning oil for heat before.

 

[Sawyer Rob]

Move to the U P and you won't have to worry about AC.

SR

 

[hube2]

In the short term it will save you money. In the long term you will never see a return on your investment if you replace what is already there.

 

[ljgordon]

Move to the U P and you won't have to worry about AC.

SR

Thats BS. I've worked up there in 100 degree weather. However, I love it there and most of the time it is nice.

 

[Sawyer Rob]

I didn't say it didn't get hot there, but it's the exception not the rule.

It get's hot in Alaska too, but no one has AC in their house.

SR

 

[KennyG]

Not sure where you are living now and exactly where you are moving, but the cost to install geothermal is high and Michigan doesn't exactly have a high A/C need. I'm fortunate to live near the lake so we don't have a lot of extreme heat. I only run my A/C a few weeks a year when the humidity gets high.

I would suggest checking with some people in the area as to how much A/C is really needed. Even using geothermal for heat it's hard to make the high installation cost make sense in my area and it never would for A/C.

 

[tractortroof]

Big payoff for heating. AC use up there? No way.

 

[CH4Ohio]

Kinda surprised by the responses so far. I would expect operating costs would by MUCH lower with geothermal. You're using a fairly constant ground temperature as your heat sink which should help a LOT with the cold up there. AC is much more efficient than ambient air exchange. Plus you get essentially free hot water when the AC is operating. In your situation, I'd install horizontal ground loops and not look back.