Geothermal and other info at Home & Garden Expo

[Pat]

Results of information gathering trip to Home and Garden Exposition: I went to the Expo in OKC Friday and Sunday for a total of about 12 hours. Got lots of information but the area of greatest interest got potentially more confused rather than clarified.

Geothermal heat pumps CAN be a good thing but I found the motivation for utilities to "PUSH" them is not altogether altruistic. More installed geothermal (or regular but they don't "work" for everyone) tends to level the seasonal load diferences for the utility. The utility tries to size production capability to meet the summer A/C demands and then has inefficient/low demands for power in the winter. More heatpumps means more wintertime electricity sales and a more constant and eficient load for the utility. If it benefits the user that is nice too but not a requirement.

I have tried to get "good" info on lifecycle costs of geothermal versus a high efficiency boiller plus a high efficiency A/C. Hard to find anyone who wants to dispense useable truth. Lots of hype little fact.

It doesn't help that 1/2 of the dealers won't travel to my area.

I was told that geothermal costs about $3700/ton, installed. Is that consistent with anyone's experience?

I also get conflicting recommendations regarding standing seam metal roofing. Since mine will be installed over OSB decking with tarred felt overlay, how thick does the metal need to be? Roof pitch is 12:12 and full length pieces will be used. Except for the potential for cosmetic damage from hail, what is the utillity of buying heavier/more expensive metal. I thought the coatings on the metal were of prime importance (I can't help it, puns just spring up on their own.)

Patrick

[wasabi]

My info and data on this subject is very dated, but in the for what it is worth dept, I offer you these thoughts:

I installed a "water-source" heat pump in a house I built in Indiana many years ago. Was pretty straight forward. We also have one in our home here in SC now.

Most use two wells...one to draw water from and one to return water back to the ground. Stats say they are far more efficent than conventional "air" heat pumps, primarily because they are working off of a relatively constant temperature differential, but I have not seen much on lifecycle. In theory, anyway, there is not much to go wrong....essentially a pump, a heat exchanger and some electronics, but Murphy can always find a way [img]/forums/images/icons/grin.gif[/img]

A long time ago I read about using a decent size pond as the water source....only problem is it will tend to raise the temp of the pond ewater in summer and further cool it in winter...which may preclude using the pond for certain fish.

Can't comment on current installation costs, but as to performance, no complaints. We have both water and air source in our current home and operation wise you would not know the difference except when it gets below 30 or near 100 degrees outside....then the water source clearly works better while the air-source limps.

There are operational cost savings with water source, but probably offset with higher initial costs and installation unless you do it yourself. Oh, one more thing...if you do go forward, keep a maint journal or good notes as some HVAC companies are totally unfamilair with these.

[Drago]

Pat - We live in Ohio and have a geothermal (closed loop) system by WaterFurnace installed in our 3700 sq. ft. house. Overall, I am pretty happy with the system....except it was undersized (or should I say incorrectly sized) which has contributed to the system using more auxillary heat (electric) than it should. The installer will be fixing this shortly. The unit is very quiet and the house always feels "evenly" heated.

The install rate per ton that you quoted is in line with what we paid. I must admit that our electric company did not push the system either. Sure, they offered a $600 rebate but that had to be accompanied by the installation of a receiver that would turn off the unit during peek demand. We passed on the deal simply because they said we should expect a 4 degree temperature change during those "power downs"....not acceptable with a wife and young kids at home.