geothermal questions and possible DIY

[Pixguy]

I now wish I had investigated geo when I built our new home 4 yrs ago. We have a lp forced air system but when they dug the well 60 feet from the foundation, they said they hit an artery and the water was almost overflowing. I wonder what it'd take now and whether it'd be advantageous to spend the money for a new furnace.

 

[truckdiagnostics]

Geothermal is more plumbing than anything else if installed with gauges and valves... troubleshooting is pretty straight forward. Its pumps and valves, plumping. I would call a refrigeration guy for the geo units before I called any HVAC guy..... or make sure the HVAC guy does refrigeration, its not a furnace. They are actually pretty straight forward. If you are not in a colder climate you ROI is harder to get to compared to air source. Ours makes all our potable hot water(in winter) So roi is much faster.
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Using a standard gas furnace as our air hander allows us to switch to 4 tons of hot water to the potable hot water indirect water heater, if the 80 gals of 115 degree water doesn't last. It then switches back to the water to air coil furnace shuts off. The way we currently have it we can't keep up in the summer. There is a timer when the unit switches between hot and chilled water. That lag time is a killer. We use indirect in the summer, we have less hot water demand anyway as we are not washing cars and trucks as much.
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its going on 28 years, however with some changes and improvements we can get it to make all our potable hot water and be even more efficient in the summer. I just can't figure out why I didn't think of it earlier.

 

[truckdiagnostics]

It's as simple as setting a furnace, tying in ductwork, supplying electric, and water supply and return.

You could use your existing furnace, remove the current evap coil and install cased water coil and all you need is a plumper and electrician. Doesn't get any easier than that. You would need a 40-50 gal electric water heater as a buffer after the cased coil. $10,00-$12,000 and you could problem get it installed for that. It been a while but cased water coil is $2,000 a climate master 2 stages is roughly $6,000 a pump water heater and piping I don't think I am that far off. These days getting the tin work done has been the hard part.

 

[IXLR8]

You had a moron for a contractor...plain and simple.

So your contractor was an idiot.

Can't say I disagree with you. The sad part is, he is the best I have found within 50 miles of my house.

 

[arto98607]

I now wish I had investigated geo when I built our new home 4 yrs ago. We have a lp forced air system but when they dug the well 60 feet from the foundation, they said they hit an artery and the water was almost overflowing. I wonder what it'd take now and whether it'd be advantageous to spend the money for a new furnace.

Heatpumps in general should have much larger air ducting system due to large air volume needed in order to operate efficiently.

For optimum performance your current forced air duct-work may need some extensive redoing depending how it was sized?

We've had a closed loop Climate Master 2-stage geothermal unit for a long time now and the air coming out of the registers is in the low 90's F when operating at the max heating output.

Cheers


PS. I think they are offering variable speed single compressor models nowadays - anyone here who has experience with those?

 

[5030]

My only comment is, directional boring (which is a requirement of any loop system is always the major expense and not something you can do yourself. Takes specialized equipment to achieve.

 

[dodge man]

My only comment is, directional boring (which is a requirement of any loop system is always the major expense and not something you can do yourself. Takes specialized equipment to achieve.

You can open dig them, it just may or may not be practical depending on how deep they need to be or things that are in the way.

 

[arto98607]

Here's what a 5' x 5' dig for a loop looks like - lucky no rocks!

 

[LD1]

My only comment is, directional boring (which is a requirement of any loop system is always the major expense and not something you can do yourself. Takes specialized equipment to achieve.

Yea, they can be open dug.

So perhaps "excavation" is the major expense.

I did my own excavation. 4 ton required 4 loops, which is 4 trenches ~120' long, 6' deep, and 3' wide. Each trench ~20' apart. So a total area about 120' x60' is all that's needed.....plus a little room to maneuver a machine and backfill.

Those 4 trenches are connected to the house off a main trench about 80' long.

So in total I dug about 560' of trench. And at 3' wide and 6' deep, about 375 yards of material.

It can be done in an day with either a full-sized backhoe or a 5t mini with a 3' bucket.

You can rent said machine for $500. And I had less than $500 in material for the loops.

 

[5030]

Correct but here the PEX must be at least 54" deep to access the ground temp. I would not want to open dig any loop system when directional boring is much quicker and easier...and the HX unit will also be a major expense. My buddy has a Water Furnace (2nd one), first one was in his other house. I don't know the cost but it wasn't a cheap date by a long shot. His total utility bill runs around 75 bucks a month except when it's real cold. Then the resistance elements in the Water Furnace come on to hold the temp and his electricity bill goes north real quick.

He still has to have a backup genny just in case utility power fails and that requires a propane tank plus the genny.

I don't much care for the output either. The air always 'feels' cool to me.

 

[5030]

Here's what a 5' x 5' dig for a loop looks like - lucky no rocks!


View attachment 782501

Works in sand, not here.

 

[arto98607]

Works in sand, not here.

It's all clay in the photo!

 

[arto98607]

..............snip.................

I don't much care for the output either. The air always 'feels' cool to me.

Maybe he should slow down the fan speed (air volume) a little bit, but it's never going to be hot air.

Low to mid 90's at best, but thats perfectly OK in my experience.

 

[dodge man]

If the electric heat is running in the geothermal it was probably undersized. We have had temps well below zero and my backup electric heat doesn’t kick in. The only time it kicks on is if you start jacking with the thermostat and turn it up more than one degree at a time.

 

[5030]

I have no idea as it's not my wheelhouse, it's his. I'll never have geothermal anyway. I have biomass and all my corn is free so I have basically free heat. I heat the house and shop and my total electrical consumption is about 300 watts per hour for both stoves. Keeo the house at 70 and the shop at 65 no matter what the ambient is and the entire cost is basically free.

 

[Popgadget]

Back up heat for a geothermal?
My open loop has worked fine for the last 40 years with no backup installed.
Duct temperatures over 100.

Of course my incoming water is always in the 50’s unlike a closed loop. I would not consider a closed loop system because of the lower efficiency and higher installation cost.

Modern air to air efficiency makes a closed loop an even harder choice to justify.

 

[5030]

Whatever. Not mine and my heat is essentially free anyway.

 

[ponytug]

Heatpumps in general should have much larger air ducting system due to large air volume needed in order to operate efficiently.

For optimum performance your current forced air duct-work may need some extensive redoing depending how it was sized?

We've had a closed loop Climate Master 2-stage geothermal unit for a long time now and the air coming out of the registers is in the low 90's F when operating at the max heating output.

Cheers


PS. I think they are offering variable speed single compressor models nowadays - anyone here who has experience with those?


View attachment 782481

Why do you say that the ductwork needs altering? Just curious, as it doesn't seem obvious to me why. (The house needs X thousand BTUs/day, whether or not it comes from oil / gas/ heat pump, right?)

All the best, Peter

 

[arto98607]

Why do you say that the ductwork needs altering? Just curious, as it doesn't seem obvious to me why. (The house needs X thousand BTUs/day, whether or not it comes from oil / gas/ heat pump, right?)

All the best, Peter

I said 'may need some extensive redoing depending how it was sized'

At lower temperature more air volume is needed in order to get the BTUs into the living quarters, but if the ducting is too small (IE. sized for system, like natural gas etc.), the air flow velocity in the ducting will become uncomfortable due to noise etc.

Yes you can get the BTUs through undersized ducts if the fan & motor are big enough, but I would no want to live in a house like that!

Hope that helps.

 

[buckeyefarmer]

I bought backhoe and did it myself.