NA - Geo Thermal Heat/Air Replacement?

[weilke]

As for AP's cost estimates, I assume they include replacement of the indoor unit too. It's 35-40 years old, it's an R22 system, and wouldn't be compatible with a new higher efficiency outdoor unit whether it be geo or air.

All of the geothermal systems I have seen had only an indoor unit. They are either integrated and have compressor, heat exchanger and air-handler in one box or they are split with the compressor/heat-exchanger in the basement and the air-handler in the attic.

If the in-ground piping is leaking, then her problem is not in the unit itself and rather than replacing it, the in-ground stuff should be fixed first.

Installing an Air-Air will require some wortk that the geothermal replacement doesn't require. For one, Freon piping needs to be run from the outdoor unit to the air-handler and an electrician needs to install the required circuit for the outdoor unit. That can be very easy or very complicated.

 

[Chip Sylverne]

But the loop is 35-40 years old. Spending the money for a new geo unit while expecting the piping to last for another 10-20 years isn't realistic IMO.

If it fails, AP will be looking at another significant expense. That's another reason I recommend an air to air system.

As for AP's cost estimates, I assume they include replacement of the indoor unit too. It's 35-40 years old, it's an R22 system, and wouldn't be compatible with a new higher efficiency outdoor unit whether it be geo or air.

When we were considering geothermal, the contractor offered a 50 year warrantee on HDPE piping, and showed us research testing of a useful life of 200 years if properly installed. It's valid issue, and worth looking into material the loop is made from and the original contract, if you have it.

 

[Maxmosbey]

So my two cents is probably not even worth that, as I have no knowledge about Geo Thermal. My brother though, put in Geo Thermal four years ago. He is a Mother Earth kind of guy, and before that, he heated with wood. But after he put in Geo Thermal, he had to find these filters, or something, and they were hard to find. So in November he was buying a new wood stove. I asked him why he was going back to wood, and he said, "Geo Thermal just isn't doing it." So that is all I can go on. His system is not more than four year old, and this might be just his third winter with it, so I don't know what is going on.

 

[flyingron]

Ron: are these "local guys" at your NC home, or in VA? We are building a cabin about 35 miles north of your Lake Norman home and am considering geothermal. Please provide me a contact if they are near me.

Thanks.

Wells

This is the NC house. I'll PM you the contractor details.

 

[flyingron]

So my two cents is probably not even worth that, as I have no knowledge about Geo Thermal. My brother though, put in Geo Thermal four years ago. He is a Mother Earth kind of guy, and before that, he heated with wood. But after he put in Geo Thermal, he had to find these filters, or something, and they were hard to find. So in November he was buying a new wood stove. I asked him why he was going back to wood, and he said, "Geo Thermal just isn't doing it." So that is all I can go on. His system is not more than four year old, and this might be just his third winter with it, so I don't know what is going on.

This is confusing possibly unless he has an open loop system. The only filters in my system are the standard forced air handler filters. There are no filters at all on the hydronic side. I'm in NC (near Charlotte) but it does get cold there a few days a year and I've never had the geothermal heat pump "not do it." Mine's doing not only the house but 3000 sf of airplane hangar/workshop.

 

[weilke]

Probably 98% of problems in geothermal systems that 'don't work' are related to faulty installation and maintenance. There is no difference between a BTU generated by a air-air unit vs. a geothermal unit. It's all math.

Oh, and I don't have any special filters. It's a closed loop. Just two Grundfoss pumps to move the antifreeze around.

 

[flyingron]

Probably 98% of problems in geothermal systems that 'don't work' are related to faulty installation and maintenance. There is no difference between a BTU generated by a air-air unit vs. a geothermal unit. It's all math.

Actually, there is. It's a function of the source temperature which with a geothermal system is usually fairly constant but with air source can often drop below useful levels.

 

[weilke]

Actually, there is. It's a function of the source temperature which with a geothermal system is usually fairly constant but with air source can often drop below useful levels.

As an end-user, it doesn't matter to me whether 50k BTU are produced from Air-Air or geo. It's the same thing. But yes, much less of an efficiency drop-off with geothermal. Run-times may go up to compensate for higher heat loss of the building, but there is no drop in efficiency of the system itself (until the loop gets really cold).


Geothermal requires proper installation and someone who knows how to open a book to maintain it. If you don't know how to measure some parameters and check them against a table that applies to the particular unit, you are not going to be able to tell whether the system performs to specs. I had to go through 2 of those techs before I found one who actually owned a thermometer.

 

[BiffJ]

We are in indiana with a GSHP system using copper tubing in the ground and R122 as the heat exchange medium. Its a very good system now though the first compressor we had blew up not long after installation. It was fixed and we've had no issues since. Our house is also all electric and heating/cooling costs are about half or less of the normal gas or oil system in this area. We run 70 in the winter and 78 in the summer and our highest bill has been just over $300 in a winter where the temps were in the teens with high winds for a little over a month. I really like this system and while it was expensive to install it has saved quite a lot. I didn't install this setup because I'm a greenie eco freak, I did it for efficiency and cost. We don't have natural gas anywhere nearby and propane is pretty much unthinkable. Oil could work but can be as much trouble as geo. I know quite a few homeowners in the area with waterloop geo and while not as efficient(or expensive) as the refrigerent loop they are still better than most other systems. . . for efficiency.

If I was having issues with a geo system I'd find someone knowledgeable to have a look and if you've already done that a second opinion isn't a bad idea. If the system is really crapped out a regular air to air heat pump isn't a bad way to go. They've developed them into pretty efficient systems which can pull heat out of the air even at low outside temps. Cost is a bit more than dropping in a gas or oil fired furnace but you get both heat and cooling which is something to consider. If you're in OK you'll need air conditioning as well and that cost should be added in with the heat system to determine real overall cost. Since you already have a heat pump installed you might not need a heat exchanger/air handler though if your system is really old its probably a good idea.....

Frank