Hi everyone.  We are building a new house this year and have our plans drawn up. It is a 2500 Sq. Foot Slab on Grade in Central Minnesota.  We have always thought GEOthermal was the way to go and have had our situation analyzed.  We have enough water and acreage to put in an open loop system.  We have gotten an opinion from a builder that the GEOthermal is not the way to go maybe because of lack of familiarity but since we have been in our last house 13 years we're pegging this one at 20.  Of course in buiding discussions the SIPS conversation has come up.  We like the idea but are wondering if the GEOthermal is actually overkill.  My thoughts were that I could have it stick built for less in this economy and the GEOthermal would make up the savings as opposed to SIPS.  Of course I am leaning towards both as the open loop system is not that expensive and can always be retofitted to a closed loop down the road without changing interior equiptment cost.  Just trying to get one one track and stay there.   By the way we're not really trying to build "GREEN" just don't want to pay utilities and maintain ease of comfort and reliabilty. 

Can't wait to hear the opinions!!!

Denny,

   Interesting scenario.  I am building a 2500 sq.ft home in S.W. Colorado.  I plan to use sips and forego the geothermal system.

   I have had geothermal in my home in MD for 8 years.  It works great. 

My reasoning for not using it is that the sips will prevent so much heat loss/gain that I will hardly use any type of space conditioning.  I think the savings will be greater going forward with the sips construction.

   The federal tax credit of 30% on geothermal , if it applies in your case, may sway your decision.  I guess you can pay now for sips or pay later for the energy consumption of the geothermal.  Good luck.

Denny,

I sent you a message via the messaging tool on this forum. Please feel free to contact me. I'm interested to hear what other have to say as well. I've debated this same thing for some time now. I still haven't come to a result yet. My house build is still in more of the planning stages.

If you are really trying to minimize utility cost you may want to look through some of the passive house standards.  SIPs can provide a great building envelope but that is just one part of the puzzle for really dropping utility costs and having a well ventilated home.

http://www.passivehouse.us/passiveHouse/PHIUSHome.html

I am also interested in this debate. Planning on an efficient home. I have a terrace lot in Minnesota that will have a walkout basement so during excavation there might be a free oppty to install a geo system but don't want overkill of the wallet!

I used them both on my last project. The nice thing about SIP's is it also reduces the energy loads so that the geothermal system is much smaller than needed with conventional framing. The main reason I used the geothermal system is that this house is ready to be converted to a zero energy home through PV. Using the most efficient systems in combination not only reduces energy costs but also the amount of PV needed to meet these goals. If you are considering making a home that will be readily converted to a solar electric home, combining these two make sense. I spend a great deal of time debating weather to use a geothermal system or a conventional or not so convention heat pump, like the Arcdia cold climate heat pump. It wasn't a simple comparison but with the new 30% fed tax credit available for the geothermal system it pushed me in this direction. Now if the Government will give better credits for making the envelope better rather than crediting you for adding an efficient system to a bad envelope this would make more sense. They do offer builders a $2,000 tax credit for building a home to high energy star standards, but these do not ussually cover the costs for accomplishing them. Tough call but if I had to chose one over the other SIP's would always be my first choice. Here is my other thoughts about geothermal or heat pumps, electric rates are not subject to the wild flucuations of say oil. Electrcity is typically regulated to make small incremental cost changes not the doubling of cost like oil did a year or two ago. It was tough to see retired people on fixed income having to make tough choices about how to spend their limited income, heat, food,or medicine not something I would like to have to make choices about once I retire, if I ever do.

Tom Pittsley
ecobuilder@aol.com
www.eebt.org