New Build in 2018: Geothermal vs NG/conventional AC

[Stimw]

I have had Geothermal since 1980 on 3 properties through the years and love it.
I currently have a 3 ton unit and it is on a 30 amp breaker but rated for 23 amps. well pump is another 7-8 amps.
Show me a heat pump with that low power draw!
I have about a 30* differential from ambient heat or cool.
Your ground temp will help the efficiency of the unit.
I went through Mammoth Cave Park (Ky) years ago and the ranger said they used the cave air for AC and it maintained a constant 54*
supply.

 

[2ndhalf]

I don't have nearly 3,000 sf to cool but when I do replace my system I think I'm doing GeoT. I just know they really pay for themselves in the Summer and you being in KY have a little more summer than Ohio.

IMO Geothermal with a small gas fireplace in case of power outage or to supliment the system in abnormally cold days.

 

[2ndhalf]

Keep in mind a regular heat pump is just a normal AC unit in the Summer and it isn't cheaper just because it is called a heat pump. Cooling a 3000sf house in the summer will be expensive unless your electricity costs are very very cheap.

 

[s219]

Operationally, its just a heat pump. Someone mentioned its more complex, no it isnt. Works the same.

The heat pump aspect of it is identical, except the geo unit uses a ground loop instead of air exchange. However, there is a fair bit of complexity in the pumps and controls for the ground loop, and there are more variables in a geo system dealing with things like ground loop temp and pressure. With a traditional heat pump it's just a fan and refrigerant-to-air heat exchanger.

In some ways I'd consider the geo to be simpler and more reliable, due to the larger heat exchange reservoir of the ground loop and the fact that we're just pumping a methanol mix through a loop of tubing. But the pumps and controls and added computer control add a level of complexity I can't fix with standard parts from a local HVAC supplier. There's also the matter of a ground loop that can fail or develop a leak, and good luck troubleshooting that.

 

[buckeyefarmer]

The heat pump aspect of it is identical, except the geo unit uses a ground loop instead of air exchange. However, there is a fair bit of complexity in the pumps and controls for the ground loop, and there are more variables in a geo system dealing with things like ground loop temp and pressure. With a traditional heat pump it's just a fan and refrigerant-to-air heat exchanger.

In some ways I'd consider the geo to be simpler and more reliable, due to the larger heat exchange reservoir of the ground loop and the fact that we're just pumping a methanol mix through a loop of tubing. But the pumps and controls and added computer control add a level of complexity I can't fix with standard parts from a local HVAC supplier. There's also the matter of a ground loop that can fail or develop a leak, and good luck troubleshooting that.

Yea, i installed 2 in my house.

 

[wngsprd]

Sounds like you have a wonderful plan for your future. You didn't specify your acreage, and whether it is open land, but assuming there is plenty if you are a half mile back from the road.

We've had a ground loop geo system since 1998, when we built a major addition to our house. We started with a Carrier unit, but had to replace it in 2011. We chose a Climate Master over the Water Furnace mostly due to which company we wanted to do business with. I think we would have been pleased with Water Furnace, but we definitely like the Climate Master. It's installed under the house in the 5' high crawl space. Designing your zones, and sizing the ductwork is important for maximum efficiency. Our heat is warm, quiet, and the unit has been reliable. In summer, it quietly blows cold air. As S219 mentioned, we get hot water, too.

We also burn wood in a woodstove all winter, and it has carried us through some power outages, but thankfully they are rare.

Eddie's tips on insulation and wrap are good points.

 

[dodge man]

We installed Geo about 4 years ago. Like already mentioned, the tax credits make a huge difference. We already had forced air LP heat with a traditional AC unit. It needed replaced when we put in Geo. Another factor we pay about 12 cents per KWH for electricity but only 8 for the geo. Check to see if your electric company offers a similar break.

For a reference, my geo unit when running heat or AC, uses a little less that a hair dryer, about 1400 Watts.

 

[LD1]

The heat pump aspect of it is identical, except the geo unit uses a ground loop instead of air exchange. However, there is a fair bit of complexity in the pumps and controls for the ground loop, and there are more variables in a geo system dealing with things like ground loop temp and pressure. With a traditional heat pump it's just a fan and refrigerant-to-air heat exchanger.

In some ways I'd consider the geo to be simpler and more reliable, due to the larger heat exchange reservoir of the ground loop and the fact that we're just pumping a methanol mix through a loop of tubing. But the pumps and controls and added computer control add a level of complexity I can't fix with standard parts from a local HVAC supplier. There's also the matter of a ground loop that can fail or develop a leak, and good luck troubleshooting that.

Not sure what is more complex....maybe other systems are different.

My ground loop pumps power up from compressor contactor. When compressor comes on, so do pumps. Simple as that. No complex stuff.

And pulling the cover off......there isnt anything more complex in there than an air-source unit.

But the BIG difference.....all that electrical stuff, wiring, compressor.....ALL INSIDE out of the weather and UV light.

A modern geo is no more complex in terms of electronics and circuitry than a comparable air-source.

Oh, and speaking of all the stuff being inside....yep. If my heat aint a working......I am diagnosing and repairing inside....not out in the freezing cold. And sure.....a leak can happen in the ground loop. But since the ground loop is plumbed (joint free) with the EXACT same stuff that has been used for 50+ years for domestic water.....and since my geo is a non-pressure system......in theory it should last much longer than my pressurized domestic drinking water.....

And most people.....use manifolds. 1-loop per ton. So my 4-ton system has 4 separate loops. So even if one of them does spring a leak......I can isolate that one until I can repair.....and still run my system at 3/4 capacity

 

[s219]

I wish I had exercised more control over our geo install, but at the time we had just had a baby and I barely had time to get a couple pictures of where they bored the wells. I would have liked to have more control over the loop plumbing to be able to isolate things if needed, and have better knowledge of how the lines to/from the wells were routed and buried, as well as exact depth. Several times I have had to dig/trench in those areas and it's been a delicate guessing game. Never hit tubing or seen the foil marking tape (which I know they put down), but I still get concerned about fill over the pipes and frost depth when extreme cold weather hits.

If I ever do it again, I would either install the ground loop myself or be in charge of trenching the piping to/from the wells, and then have some redundancy with a manifold and valves, and perhaps an extra loop or well for backup. To me the labor/time are the big expense, but if you can control that, then it makes sense to go the extra mile with the ground loop and plumbing/controls.

 

[kenmac]

Since it's new construction. check on the installation price of installing a mini split system for the entire home. Very efficient for heating and cooling.