New Build in 2018: Geothermal vs NG/conventional AC

[LD1]

A "pro" will do a load for both heating and cooling. Design temp indoors vs design temp outdoors. Generally in our area, outdoor temp design for heating is either 20 or 17, and for cooling 95.

Biggest issue with load calcs is garbage in, garbarge out, but if they're done right, they really don't lie.

I am not saying that they arent doing the load calcs right.

I am saying that they choose to size a unit based on the cooling load vs heating load. Which makes the unit WAY too small for cooling in my ohio climate.

It would be like sizing an arizona or florida or southern texas geothermal unit by its heating needs.

 

[Sigarms]

I am not saying that they arent doing the load calcs right.

I am saying that they choose to size a unit based on the cooling load vs heating load. Which makes the unit WAY too small for cooling in my ohio climate.

It would be like sizing an arizona or florida or southern texas geothermal unit by its heating needs.

You need to size the system for BOTH heating and cooling, as well as ensuring you have the correct size duct for CMF's needed in heating and cooling.

That's why you do a cooling load at 95 degree outside air temp and a heating load at 17 or 20 degree outside air temp (at least in generaly for NC).

 

[truckdiagnostics]

Can't see where the additional cost of putting in loop for geothermal(ground source heat pump) in your area would be worth it. Air to air heat pumps, much more efficient these days. I have geothermal. and have it heating house shop and pretty much everything, but I am a whole bunch further north. Your area I would look long and hard at a air source heat pump.

 

[mikester]

I am building a new home, roughly 3000sqft higher end home this year. (or at least planning stage with architect).

Location is Lexington KY area. I have access to and will run Natural Gas to the house for range and fireplaces. The run will be long, likely 1/2mile at least across my land.

I am soon to be 50yo and I'm planning on another 30 at least. But I am trying to be pragmatic, not pie in the sky.

My question, to you who have gone there and have more knowledge: would you add a Geothermal Heat pump or conventional Nat Gas/AC system to this house in my situation? While $$$ is an issue, I'd like to know your thoughts on the 'intangibles' as well such as 'down time, noise, comfort, install (new home) etc. ' and would you personally, do it in my situation?

I am ambivalent. I'd like the 'green-ness' of the geothermal just as I'd like it for Solar, however, I don't believe Solar is a wise investment at this point, and I don't know about geothermal.

What are your knowlegable thoughts about it in my situation? Why WOULD YOU or WOULDN'T YOU?

We will be putting in 2 horse barns, well away from the house and will have about 1/2mile of driveway as well. Just to add some info if that brings up any thoughts.

If you are still designing take a serious look into passivhaus and passive solar. If you super insulate you can easily go with a cold climate mini split air sourced heat pump which will be a lot cheaper than geothermal. The other benefit of minisplits is no ductwork and they are very quiet...they can be quieter than most forced air systems I've seen.

In your climate - if you design it right your heating and cooling bills can be negligible.

Around my neck of the woods a geothermal system will cost about $30K installed. You can get an ASHP for less than 1/3 to 1/5 the cost. Even cheaper if you insulate well.

Spend the money on insulation. Considering the lifetime costs of building a home, 80% of the cost of a home is in the operating costs to heat and cool.

Check out homepower.com there's lots of very good info there.