Geothermal

[John Dirks Jr]

I'll be inspecting a house with geothermal heat exchange. I understand the general concepts of these systems but would like information on inspecting them.

Other than typical air handler and distribution issues, what should I be looking for? Are there any specific procedures I should perform, or avoid performing?

Thanks in advance for any input.

[David Meiland]

I've only looked at a few, but when I have the complaint is high energy consumption and lack of magical free heat, and the problems are difficult to assess. The design and performance of the ground loops has to be right, and it has to be installed right. The amount of pump energy used is often very high. That's probably outside the purview of a home inspection but if I were the buyer I'd want a bill history from the utility company at minimum, and probably a thorough HVAC checkout to determine that the various temps and flow rates were within range.

[kurt]

It's a ground source heat pump. It's good to use the right terms. Geothermal is like Iceland or Yellowstone where you're taking heat directly from the Earth.

I've looked at enough of them to know I don't want to pass judgment on any of them. Someday, maybe, but for now.....no way.

I'd recommend getting the best engineer in your area that's intimately familiar with these systems. There's too much to consider and look at to begin getting into it here.

I did a big job a couple weeks ago with a 3 zone system. Water Furnace brand.

I thought it looked pretty good until the engineer I hired went through it all and determined there wasn't enough flow rate for one of the zones. The installer had cheesed on a zone, and now they have to tweak and fiddle with the refrigerant and cycling to get it to work somewhere close to right, but it will never be right until major work is done. This all came out in disclosures after the fact where they allowed as to how it "wasn't quite right". Typical realtor bullshit and obfuscation. It's one thing when someone lies about a roof, and quite another when it's a >6 figure heating system.

This was on a $4 million home with a supposedly good engineering firm. And they screwed it up. I'd have never known.

These things are kind of like radiant in the early days....guys kinda making stuff up. Be really careful and get an engineer to help.

[John Dirks Jr]

Thanks for the help.

So far I'll correct my terminology, recommend they seek information on energy consumption both prior to and after the system installation and recommend a specialist be hired to do a thorough evaluation.

[John Dirks Jr]

In a mid Atlantic state like Maryland, do you think a ground source heat exchange system (if properly set up) would be more beneficial in the heating mode or cooling mode?

[kurt]

Focusing on HVAC technology as the center concept of a building is idiotic. Building envelope design and construction should drive the process.

If one has an appropriate envelope, one does not need 6 figure complicated heating and cooling systems.

[Scottpat]

This past year I was involved with a home (called in by the bank when the loan was advanced to 70% and home was near 40% complete) and it had 3 ground source(drilled wells) systems. The HVAC line item cost was $77,000 and the value of the home was $875,000! Just a ridicules percentage of the value of the home vs the cost of the HVAC. They are expensive.....

[Ben H]

This past year I was involved with a home (called in by the bank when the loan was advanced to 70% and home was near 40% complete) and it had 3 ground source(drilled wells) systems. The HVAC line item cost was $77,000 and the value of the home was $875,000! Just a ridicules percentage of the value of the home vs the cost of the HVAC. They are expensive.....

Did it have fiberglass batts in the walls too? Kurt's right. The cheapest BTU you'll ever pay for is the one you never have to.

[Scottpat]

This past year I was involved with a home (called in by the bank when the loan was advanced to 70% and home was near 40% complete) and it had 3 ground source(drilled wells) systems. The HVAC line item cost was $77,000 and the value of the home was $875,000! Just a ridicules percentage of the value of the home vs the cost of the HVAC. They are expensive.....

Did it have fiberglass batts in the walls too? Kurt's right. The cheapest BTU you'll ever pay for is the one you never have to.

No, it was sprayed on cellulous in the living area and closed cell foam in the basement and attic.

[Ben H]

This past year I was involved with a home (called in by the bank when the loan was advanced to 70% and home was near 40% complete) and it had 3 ground source(drilled wells) systems. The HVAC line item cost was $77,000 and the value of the home was $875,000! Just a ridicules percentage of the value of the home vs the cost of the HVAC. They are expensive.....

Did it have fiberglass batts in the walls too? Kurt's right. The cheapest BTU you'll ever pay for is the one you never have to.

No, it was sprayed on cellulous in the living area and closed cell foam in the basement and attic.

They are ahead of the game in Nashvegas!