Geothermal experts needed

[Crash13]

I just posting this same thread in the "insulation" forum, but it also has to do with HVAC so I decided to put a copy in here as well. Ok, first off, I'm going to be building a new house this summer. It'll be a 2500 sqft Cape Cod, however, only about 1900-2000 sqft will be finished for awhile. There will be a good chunk upstairs that will remain unfinished until I can put some money together to take care of it. Anyhow, my builder has presented me with many options, and one thing that I've been racking my brain over lately is insulation and HVAC. I've decided this much, I'm going to keep my exterior walls at 4" (nominal) thick. Also, I'm going to be setting up my own geothermal system. The two things I can't figure out are: what insulation to go with and what size geothermal unit to use? I'll have an air-to-air exchanger installed and my basement walls will be encased in 2" thick foam insulation. So my question is, is celluoise insulation worth the upgrade? My builder is telling me it'll be about $6,000 extra to upgrade to celluoise over baton. My other question, which is probably in the wrong forum, but follows along with the same topic...... how big of a geothermal unit should I be looking at? 3, 3.5, or 4 tons? Ohh, I live in southeastern michigan. I understand that going overboard on the cooling side of things is bad because the unit will never run long enough to pull out humidity, but what if there is a variable speed fan option where I could run the fan very slowly during cooling? There is also an electric heater option that basically turns on only when absolutely needed during the coldest of nights. However, someday I plan to install a wood stove in the living room, probably about the same time that I finish the upstairs. I dont' want ro ramble much more, so if you need anymore info please ask. Thanks.


P.S. if anyone here knows anything about geothermal systems, please private message me, as I have a number of questions about the intricacies of it.

[rabadger]

If you are not going to finish the home because of budget issues The geothermal system will break the bank.

[bkrahmer]

Anybody wanting to charge you $6000 extra for cellulose is absolutely insane. The product is 30-40% cheaper than fiberglass, and takes just a bit longer to install... Read my other recent post on my experience with cellulose.

[rabadger]

You need the load calculations and a good equipment rep that knows his applications. Not just a salesperson.

[Crash13]

Anybody wanting to charge you $6000 extra for cellulose is absolutely insane. The product is 30-40% cheaper than fiberglass, and takes just a bit longer to install... Read my other recent post on my experience with cellulose.How can i tbe better and cheaper? Or is it not better?

[bkrahmer]

I think it's a great product for certain applications. Attics for one, and if you wet-blow, walls also. It is better then fiberglass for several reasons. One, it performs much better at low temperatures. Second, it is a better sound insulator, and third, it has a higher R-value per inch than standard fiberglass. Oh yeah, it's a better infiltration barrier as well.

How can it be cheaper? It's just shredded newspaper with boric acid added. Manufacturing costs are probably $100 per ton, and they sell it for about $700 per ton.

[Sparks]

Regarding diy geothermal, get an engineer or manufacturers rep. to spec. out and size. (again, not salesman). This is big on a geo-thermal system espicially from what I've read on them. This would be worth any fee a competent mechanical engineer may charge in my opinion.

[Crash13]

Regarding diy geothermal, get an engineer or manufacturers rep. to spec. out and size. (again, not salesman). This is big on a geo-thermal system espicially from what I've read on them. This would be worth any fee a competent mechanical engineer may charge in my opinion.I am a mechanical engineer, and both my parents are in the hvac trade. We just don't have experience with geothermal, yet. I don't think it's nearly as complicated as people make it out to be. Energy is energy. A house needs so much, no matter how it's transferred. Anyway, I've decided to go with a 3 1/2 ton unit with a variable speed fan and electric fan back-up. The things I'm not 100% sure of are: what kinda liquid to run through the loop, and where to get the piping (polyethylene HD)?

[Sparks]

That's wonderful but I sort of meant an engineer who specializes in these applications and thermodynamics in general. But of course being that you're an engineer with family in the hvac trade you're aware of all the variables that are involved here. Some that post questions here are not aware that there is a science to things like this and are looking for simple answers. If you choose not to perform of heat loss/ gain calculation, that's up to you. Energy is energy, that 's true, transferring it effeciently is the key. But I guess you're right, it's not that complicated.