Ground Source Heat Pump

[iagsxr]

I'm doing a 36x48x14 addition on my existing 30x 63 x 10'6". The addition will have floor heat. The existing building has a nice floor already so it will be forced air. Both parts heated and A/C'd. Was planning on just traditional gas boiler for addition and furnace for existing. I got into it a.little bit last week with the contractor I was planning on using so went and spoke with a different one. He was like, have you considered geothermal?

I hadn't mainly because didn't think I had the space. He said they'd go vertical with the wells.

Can anyone get me up to speed or point me to a knowledge resource? I'd like to be better informed before I have any serious discussions with this contractor. Which will be towards the end of the week.

I also want about a 400 sq/ft snow melt strip. Everyone acts like this is a huge deal. At my carwash I have about 700 sq/ft with snow melt. Doesn't seem like rocket science to me.

 

[jkeyser14]

Read up on them here, there's a ton of good information.
http://community.geoexchange.org/

I have a system with closed loop vertical wells, it's been installed for about 4 years now and I can't say enough good things about it.

 

[jack stand]

Here's another link to a forum. http://www.greenbuildingtalk.com/Forums/tabid/53/afv/topicsview/aff/13/Default.aspx
The high(er) installation cost makes for a long payback period and is a negative for a lot of folks. I have only heard good things about geo therm., but I think that an expensive system like this requires proper, professional design services. My guess on the ice melt is that it would be VERY taxing on a geo-t system where it's no big deal when burning conventional fossil fuel based sys. You might run it seperately.

 

[kd3pc]

My dad heats and cools almost 4K sq feet of house with geothermal using vertical wells, IIRC, there are three wells and it has been installed for 6 or 7 years. Not a bit of problem. He has a pump unit in the basement and the house is divided in to three or four zones. He has in floor and several "radiator boxes" that are warm to the touch.

It was a bit expensive to install, about 2.5 times conventional HVAC (wells and low tox antifreeze were the biggest hit)....BUT it heats and cools for about $60-70 a month and the pump can easily be run off a small fail over generator, as it is a low current device, unlike a conventional heat pump or air conditioner.

The only con I can think of is that it is deadly quiet and it takes a few hours to make a dramatic change in temp...

He is just outside Winchester, VA so it does get cold and hot.

 

[theoldwizard1]

I hadn't mainly because didn't think I had the space. He said they'd go vertical with the wells.

Actually, vertical is the most common. They just come in with a water well drill and say, "Where do want it and how deep ?"

Is this going to be one giant building or is the new section going to be partitioned off ? If not partitioned I would be concerned with warm air moving over to the radiant floor side, especially at the ceiling. Ceiling fans help a lot with radiant floor heating.

If you are going to pay the money for the well(s) (you may need more than one) you should find out what it would cost to convert the other half to heat pump. There is potentially big saving, especially on the cooling side. Again, depending on how it is partitioned, you may want zoned heating and cooling or possibly 2 heat pumps.

You need to find a highly recommended, geothermal heating and cooling company to work up some estimates. More than one estimate never hurts.

 

[theoldwizard1]

My guess on the ice melt is that it would be VERY taxing on a geo-t system ...

No big deal if the total system is sized for it.

 

[iagsxr]

Thanks for the responses so far.

There will be a partition wall between the two halves. It will have an overhead door in it, but will rarely be open.

Using the heat pump on both parts is sort of the point. Right now we just have a shell so rather than buying a boiler and a furnace, just buy a big enough heat pump and air handler is what the guy was getting at.

I'll look at the sites that have been suggested I'm sure this is covered there;. The tax credit, 36% the first year? If it's an actual credit that should do a long way toward making up the cost difference, no? He said there were some other incentives as well.

 

[theoldwizard1]

... The tax credit, 36% the first year? If it's an actual credit that should do a long way toward making up the cost difference, no? He said there were some other incentives as well.

Time to talk to your accountant !