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Costs for Geothermal?

Started by dalebert, November 07, 2008, 10:26 AM NHFT

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dalebert

Anyone have any notion of what it cost to install a geothermal? Perhaps to incorporate it into the existing distribution system? Seems like it might be worthwhile for a large enough home and may pay for itself in time.

This site says the cost of installing a geothermal unit is about the same as a traditional forced air system and that it can supplement other systems. Sounds promising. Seems like the cost is easier to justify if you don't already have air-conditioning because geothermal can cool as well. Based on how it works, seems like it would cool even more effectively than traditional air-conditioners but I don't know for sure.

http://www.alliantenergygeothermal.com/stellent2/groups/public/documents/pub/geo_001407.hcsp

SpeedPhreak

I can't find the issue - but Home Power magazine had a DIY article on building a solar collector/geo cooling system.

http://www.homepower.com/search/results/?sort=relevance&search=geothermal&columnid=&resourceid=&energyapplicationid=&articletypeid=&readerlevelid=&regionlocationid=&authorname=&issue=

lots of articles.

Sorry I don't know much outside that.

dalebert

I don't want to fiddle with solar just yet. The technology isn't quite developed to the point of being cost-effective. I think it's getting close though and I'll be keeping an eye on it. May not be very viable in NH for a while. I think CA ppl will be able to justify it easier, sooner, with their weather patterns.

Geothermal, however, could make a lot of sense in NH where our winter heating costs can be quite significant. And it's kind of icing that it can be a cooling system in the summer as well considering that many NH homes don't bother with cooling.

SpeedPhreak

I didn't mean solar electric.  The article I refer to consists of an insulated out building w/a good southern exposure.  The south side is all glass & there is a liquid (don't remember if it was an anti freeze or H20) in black pipes.  The liquid is heated then carried underground to the house to heat water & for radiant floor heating.  In the summer the liquid is re routed to only flow threw the under ground pipes & thus cooled - cooling the floor threw the same radiant floor tubing.

As far as the site goes - they have "real" geo thermal info too (I know what I described isn't exactly what you are refering to).  The whole magazine is about alternative energies for the home & focus a lot on DIY.

ByronB

There are a lot of ways you can save energy, the trick is finding something that is cost effective...  it is awfully easy to find a way to use alternate energy only to find that you need to run a circulating pump(s) to get at it (that may use more energy then you are getting) and you may find out that your payback on your investment is a LONG time, plan carefully if the end goal is to save money.

The problem with geothermal is the ground is about 50 degrees (varies though) consequently it is a lot more efficient to cool with geothermal then it is to heat with geothermal, this makes geothermal more ideal for warmer areas where heating isn't as critical as in NH. In order to get a (traditional) geothermal system you would have to drastically oversize the system to meet your heating needs.

I'm not sure about the south facing wall with radiant floor heating/geothermal with floor cooling... cooling through the floor is a poor may to do it, it may sorta work in NH but in most places would just result in a hot, humid house with a constantly damp floor from condensation. Heating of course would be entirely dependent on how much sunlight you get on that wall... it wouldn't work at night when you need it the most, it may a better idea to simply have a lot of big windows facing South to get heat into the building.


MengerFan

Here in the Ohio cornfields, I spent around $15k on geothermal. Went from paying hundreds per month on propane to paying about $20 extra per month in electricity during the winter and having a lower electricity bill in the summer. Totally awesome. With all the tax breaks, the savings is more than enough to make the payment on the 5-year loan to pay for the system.

dalebert

Yes, I'd heard 50 deg ground temperature. In NH, that's quite high compared to the outside temp in the winter. The idea is to use a heat pump to draw that relative heat from there and pump it into your home. It's working like an air conditioner in reverse. I thought it was due to this relatively small temp difference vs. the outside, that geothermal was viable in NH.

Lloyd Danforth

You need optimum or at least adequate Sun attitude for Solar.  All you need is a large enough area of dirt that you can dig down deep enough for Geothermal.

KBCraig

The huge variable in a geothermal installation, is rock.

If you can drill in dirt, it's obviously much cheaper than drilling rock, and they don't call it the "Granite State" just because it sounds cool.

dalebert

Quote from: KBCraig on November 07, 2008, 08:25 PM NHFT
The huge variable in a geothermal installation, is rock.

Crap, I'd forgotten about that for a min.

margomaps

I've read that a geothermal system is ~ 1/3 more expensive than a good "conventional" system (fuel-oil or propane or gas boiler I guess).  That 1/3 might be a little higher due to labor for drilling/excavation costs in NH because it's so rocky.

Lloyd Danforth

Actually, I've seen a lot of digging in NH and I haven't seen any more solid rock than I have anywhere else in New England.

dalebert

I don't understand why it has to be a forced air system. Seems like a heat pump could be used to heat or cool liquid for radiators or baseboard systems, or whatever.

ByronB

I don't see how people come up with idea that geothermal is about the same price as a traditional system... basically you have pretty much all the same expenses PLUS the real big expense of digging around in your yard installing ground loops and don't forget... a backup heating system is pretty much essential.



dalebert:
The problem with using a heat pump for cooling via radiators is the moisture, it is kind of like taking a cold beer out of the frig, condensate forms on the radiators and on real hot humid days I've seen a room cooled with radiators in the ceiling have its own rain shower... I suppose it could be fixed by insulating all the piping and putting drain pans underneath the radiators but it still won't drop the humidity like a forced air system will.

dalebert

Quote from: ByronB on November 08, 2008, 02:12 PM NHFT
dalebert:
The problem with using a heat pump for cooling via radiators is the moisture, it is kind of like taking a cold beer out of the frig, condensate forms on the radiators and on real hot humid days I've seen a room cooled with radiators in the ceiling have its own rain shower... I suppose it could be fixed by insulating all the piping and putting drain pans underneath the radiators but it still won't drop the humidity like a forced air system will.

Oh, that makes complete sense. I was only thinking of the heating aspect when I said that.