Hey there, I'm new to these forums so if I'm posting a question that's been addressed before feel free to slap me & point me there :)

  We are in the preliminary stages of designing a home on a 4 acre wooded lot and while the climate is mild here, I'd like to make some good choices in the design.  The builder is an open-minded friend of mine with some solid experience.
  The home is one we may only be in for 3 yrs, or possibly for 15 yrs if we like it there.  The lot is in a "subdivision" that has rules against solar panels, etc. unless aesthetic enough to be approved by the developer.  I'm looking at geothermal, solar options, wondering if a simple Heat pump, efficient HVAC system & good insulation might be a better way to go. 
  I could really use some comprehensive advice on which options are available to me that are cost effective if I don't stay in that house long, but will carry me long-term with options to maybe alter the design a little more if I stay longer.

Hi Flapinux!

Welcome to the Green Building Talk website...

Your situation reminded me of the song by Clash, Should I Stay or Should I Go. If it is more likely that you won't stay longer then 3 years, I would go with a more conventional heat/cooling system. However, I would upgrade the ductwork sizing and internal noise isolation of the ductwork to accommodate a future geothermal system. This way you keep the cost down now and if you move soon less money out of your pocket. If you do stay, upgrade the system in 10 years.

The biggest factor here in my opinion is cost recovery time. If you don't stay long enough for a geosystem to reach the payback point, then it is money out of your pocket. Yes, it may increase the market price of your home, but with the current housing market, I sure wouldn't be betting on it. Most people buying homes don't understand the benefits of a geothermal system. All they see is a system that can look very complex compare to more conventional heating cooling systems.

Hope you new home comes together well for you.

Regards,

Eric D

What are the energy costs in your area? In my area, it's a 3-5 year payback compared to propane, but an 8-12 year payback compared to natural gas. Of course, Utah has the lowest price for natural gas in the lower 48 states..., but elsewhere it's pretty expensive. It might be a quicker payback than you think. Especially if you look at an EarthLinked DX geothermal system.

I'm not sure the cost of propane where' we're moving. Thanks for the tip on EarthLinked DX - I'll check into that. I also need to find out of there are local installers for it & support in case I have problems right? Are geothermal units louder than forced air? Is that why you need to insulate the duct work? I think I need to compare some systems & see what it would cost - my wife's totally ready to do it if it'll fit in a $20k budget.  It looks like ECR or EarthSource Energy Solutions is the way to go?

Flapinux,

The water to air or DX systems typically move more air then a fossil fuel furnace. This is due in part to the lower duct temperature as compared to fossil fuel. With more air movement there is also more noise potential. There is also duty cycle to consider, a properly sized geothermal system will have more run time when compared to fossil fuel systems too. By treating the ductwork accordingly by adding sound absorber, the geosystems can be far quieter the most any other system on the market.

You are going about choosing a geosystem the right way by doing your research. Make a choice you feel comfortable with. It is also a good idea to calculate the payback point.

Best of luck with your new system,

Is there a good formula for calculating a payback point? There is a installation cost with either a forced air system or a DX heat pump, so I suppose you'd subtract 1 system from the other, then factor in the cost savings per year of the 90+% efficient forced air system vs the geothermal operating costs (which is what I don't know how to find out).

Once you have your home designed complete contact the companies that you are thinking of doing the installation and have them calculate the payback based on your local energy cost. Most don't mind doing the calculations and normally there isn't an obligation to get this data.

Regards,

The Energy Audit program from Elite Software does a wonderful job at calculating the payback. To get the payback, you need the following: accurate heating and cooling loads for the house, electricity costs, propane costs, price for a gas heating system, price for the geo system, the COP of the geo system, EER of the geo system, and the capacity of the geo system when in full load (cold and hot outside temps) conditions.

If you post all except the COP, EER, and capacities, I could give you an idea of the payback from an EarthLinked system. Oh, I'd need to know horizontal or vertical for your ground loop.

For 6,000 sq. ft., you'd be crazy not to put in geothermal. It should pay back fairly quickly.

I'm not sure horizontal or vertical... the lot has a nice drop which provided our required Walk-Out basement. Remember, this is 4 acres too - will a slope affect how I proceed?

Depends on how much slope. Drilling is usually what we do, but most people don't have 4 acres.

Would putting the copper under the house save money on installation? We already have to dig the basement, why not simply put it under the basement? Has anyone done this?

It can possibly save money, but may cost you a little time. The money it may save would be in the range of $500. It's not that big of savings to me to justify causing a scheduling problem. Yes, we've put the loop in a crawl space under a house.

Is there a chart showing cost/efficiency comparisons between horizontal/vertical open/closed loop?

Yes. I have that, but I don't know how to attach it on these forums.

Could you simply email it to me?  Thanks :)

the messaging doesn't work. What's your email? Mine is [email protected]

my email's in my profile, but I'll just email you