Central heat and air unit (standard vs geothermal)

[s219]

We've had Geo installed for a year and a half now. This was new construction build so our cost included ductwork and desuper as well. Total cost was $38,000 for two 4 ton units with 6 total zones including basement. (We could have gotten by on 4-5 tons easily but that's another story) Subtract 30% tax credit and $750 per ton rebate from utility and our total cost was about $21,000. We are very happy so far. One thing nice about system is how quiet and comfortable the house is. Set the temp and forget it. You don't even notice its running.

Performance wise I'm happy so far. We are all electric with 27' vaulted living room and loft and 10' ceilings throughout. Total sq/ft is 3550 first and second floor and we are using less electricity than our old home of 2,100 sq/ft with even bigger savings during the winter since the old house was on propane.

That could loosely describe our experience. Our electric bills have been the same or lower than our last house, which was 2/3 the size. I am sure some of that is due to our insulation package. The old house had 4" walls and fiberglass insulation. New place has 6" walls and spray foam / cellulose insulation, and is noticeably tighter. The old house had sweat on the siding every morning in summer, due to the cooled inside air not being insulated well enough. Have not seen that one bit on the new house, and it stays cooler and more comfortable to boot.

The only problem we've had, unrelated to the geo unit, is with duct damper motors. There are two, one in the crawl and one in the attic, that let us condition two zones with a single unit that has a variable stage fan (several of the ClimateMaster geo units are setup for this). Great idea in concept, but I have replaced the crawl duct damper motor three times and the attic damper motor once (in two years). I finally switched to a totally different brand of damper motor the last time I replaced the unit in the crawl, and so far it has outlasted the others. Still have one of the old motors in the attic. Our HVAC guy said the original supplier (Hansen) changed something and now their motors are failing, some within days/weeks of installation.

Sometimes it's easy to notice when a motor has crapped out, other times it takes a couple weeks to realize. And since they can fail open or closed, it's not always clear which one is the problem. Last time I was convinced the motor in the attic was stuck open, when in reality the one in the crawl was stuck shut. Of course, both places are awful to work in, especially the attic in summer. The crawl is conditioned, so the only issue is spider webs and working in a tight space. While one corner of our crawl has a 7' ceiling and a slab, the damper is located on the opposite corner where it's only about 2' high....

 

[JamesHW]

We've been considering Geothermal for a house we are planning to building the lower Adirondacks. A horizontal ground loop would seem viable since we have plenty of space to excavate in an unimproved field next to the proposed building site that could be excavated. One challenge to the decision is the makeup of the subsoil that is all sand (left from when the pro-glacial Lake Albany drained about 10,500 years ago) which presents a conundrum. Sand when wet is one of the best conductors of heat and when dry is one of the worst. So the sand, is an advantage in that excavation for the loops is a potential DIY (zero rocks anywhere on the property) that could make the project less expensive, but my concern is in a drought the loops would perform poorly. The entire property appears to have shallow aquifers (springs scattered about and a shallow well, all at around the same level), so my concern may be miss-placed.

The house we are thinking of would be a barn structure (we have the timbers) clad in SIPs, so very well insulated and probably easy to keep comfortable year round no matter how we condition the house if it is well designed.

Added to the calculation is we have NG available from the road 500 feet from the house, so NG heat is possible. Also batting around the idea of a high efficiency wood boiler (80 acres, mostly woods) seemed attractive, but if something happens to me somehow I do not see my wife bucking logs.

So for us geothermal is still interesting but will require more research.

 

[truckdiagnostics]

No, if anything more bells and whistles exaggerate issues of poor design.

I would agree for standard AC but not Geo. On the expensive geo units they have variable loop pumps, compressor and fan speed. This should make up for over sizing, in a way that your standard Air cooled condenser and evaporator can only dream of. That is my understanding of how water furnace is doing it, this of course will not make up for under sizing. In our case we are controlling the loads. The domestic potable water is priority, then it switches to forced air then garage floor. We are using electric hot water heaters as reservoir tanks. For domestic potable hot water the electric heater brings it up last few degrees so geo doesn't have to work so hard. On the garage floor if I need a specific temp and it is cold out I can turn on the electric elements in the reservoir tank. This allows us to modulate the loads or help out on the extreme ends with out the need for over sizing. Plus when we originally designed variable displacement everything was not available. The system in the house works very well. The shop and office that is a different story. If we get a real cold winter I can get the loop to cold. It is too late now, but I think if I made the loop bigger, that would have solved this issue. When the system was originally designed it was not designed for the office add on. What we are looking to do is put forced air gas in the shop to help out geo thermal when we open and close the shop doors. Then we would put an A coil in, making office priority and I would have AC in the shop.:cool2:

 

[truckdiagnostics]

We've been considering Geothermal for a house we are planning to building the lower Adirondacks. A horizontal ground loop would seem viable since we have plenty of space to excavate in an unimproved field next to the proposed building site that could be excavated. One challenge to the decision is the makeup of the subsoil that is all sand (left from when the pro-glacial Lake Albany drained about 10,500 years ago) which presents a conundrum. Sand when wet is one of the best conductors of heat and when dry is one of the worst. So the sand, is an advantage in that excavation for the loops is a potential DIY (zero rocks anywhere on the property) that could make the project less expensive, but my concern is in a drought the loops would perform poorly. The entire property appears to have shallow aquifers (springs scattered about and a shallow well, all at around the same level), so my concern may be miss-placed.

The house we are thinking of would be a barn structure (we have the timbers) clad in SIPs, so very well insulated and probably easy to keep comfortable year round no matter how we condition the house if it is well designed.

Added to the calculation is we have NG available from the road 500 feet from the house, so NG heat is possible. Also batting around the idea of a high efficiency wood boiler (80 acres, mostly woods) seemed attractive, but if something happens to me somehow I do not see my wife bucking logs.

So for us geothermal is still interesting but will require more research.

In your case I would consider gas furnace then water coil using well water for cooling. Put in a variable displacement well pump. I have done it for farmers, using the well water for cooling before giving it two the cows. Works real well. Cows drink more cause the water is warmer too. This system works real well with a wood boiler, you already have most of the stuff just have to flip few valves. That is provided using boiler for potable hot water.

 

[MacLawn]

JimRB in Covington, can I ask how much your monthly bill averages? My place is almost exactly like yours, minus basement (1,800 square feet), it's in Columbia County, exact same clay and weather as Covington, 80 miles east off I-20. Also Georgia Power. House is total electric with my own well, so my power bill is for everything and runs about $150.00 a month keeping 73° summer, about 75° winters with wood stove. Last month, July 2015, was $224.00. I just have a hard time paying that $16,000.00 after rebates for the trenches and geothermal heat pump. I do want it though. I wonder if my man here installed yours? He does most of his work in Atlanta area he said.

 

[jk96]

JimRB in Covington, can I ask how much your monthly bill averages? My place is almost exactly like yours, minus basement (1,800 square feet), it's in Columbia County, exact same clay and weather as Covington, 80 miles east off I-20. Also Georgia Power. House is total electric with my own well, so my power bill is for everything and runs about $150.00 a month keeping 73ｰ summer, about 75ｰ winters with wood stove. Last month, July 2015, was $224.00. I just have a hard time paying that $16,000.00 after rebates for the trenches and geothermal heat pump. I do want it though. I wonder if my man here installed yours? He does most of his work in Atlanta area he said.

You should probably ask what your avg. KWH usage is. My house is an extra $150 per month more than my old house 2 miles away using the exact same KWH usage during peak months. Two different utilities and drastically higher $ per KWH at the new house. KWH will give you a much more accurate comparison. Don't forget the difference in building envelope. Makes it really hard to compare two different houses.

 

[techman]

I need to take infared pictures of my house in the summer and winter. I gather it is relatively cheap to get an IR adapter for an Iphone but I live in a Droid world.

Look at a Seek camera or a Flir One. Both available on Amazon, both compatible with Android or Iphone. $ 250 for either

paul

 

[truckdiagnostics]

Look at a Seek camera or a Flir One. Both available on Amazon, both compatible with Android or Iphone. $ 250 for either

paul

Have you tried them for finding in floor heating pipes in concrete? And if you have have you had any luck using them to any accuracy once the floor as warmed up?

 

[techman]

Have you tried them for finding in floor heating pipes in concrete? And if you have have you had any luck using them to any accuracy once the floor as warmed up?

I have a dedicated FLIR unit myself. You can easily see the location of radiant tubing under floors or concrete. Of course you need to have heat on, but they are then easily seen.

paul

 

[kenmac]

JimRB in Covington, can I ask how much your monthly bill averages? My place is almost exactly like yours, minus basement (1,800 square feet), it's in Columbia County, exact same clay and weather as Covington, 80 miles east off I-20. Also Georgia Power. House is total electric with my own well, so my power bill is for everything and runs about $150.00 a month keeping 73ｰ summer, about 75ｰ winters with wood stove. Last month, July 2015, was $224.00. I just have a hard time paying that $16,000.00 after rebates for the trenches and geothermal heat pump. I do want it though. I wonder if my man here installed yours? He does most of his work in Atlanta area he said.

It's been hot here this past mo..I'm on Alabama power / same owner as Georgia power.. I cool 1800 or so SQ. to 74* .. I have 2 swimming pool motors that run about 10 hrs a day every day.. I have a hot tub with 2 motors & elec heater,that keeps the water to 94* and runs every day..I have 2 dusk to dawn lights ,shop lights, shop refrigerator, water cooler,drink machine, and various tools that I run in the shop daily..I have a 14 seer 3 ton unit for cooling with 90 + gas heat.. Just got my power bill for the mo.. 393.71