Quote:
Originally Posted by tis
I don't know the whole deal, but in talking to a local well driller, he was going to a new house that is being built on the lake to dig 10 wells. I don't know if these were test wells or they were all going to be used. I thought they were all going to be used, but I could have misunderstood.
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No driller would set out to drill 10 "test wells." If he's drilling for water, he will have a fair idea of how deep a well likely will have to go in a particular location to get adequate flow for domestic use, based on other wells drilled in the area. If he set out to drill 10 wells, whether to hit water or just to get so many holes in the ground for grouting in U-tubes for a ground connection for a geothermal heating system, then likely that was the plan, as part of an overall project. If this is indeed for geothermal heat, the number implies support for a rather large system, and for construction of a new house it represents a huge lost opportunity in design of the house.
If the drilling cost for 10 wells were to be spent instead on the design of the house's exterior shell, into the realm of superinsulated, the result would be a house with a very low heat loss relative to its size, and requiring a very small and correspondingly less expensive heating system to keep it warm in winter and air conditioned in summer. It also would be notably more comfortable year-round, without the cold spots often noticed in ordinary houses when the temperature outside takes a nose dive. Moreover, the extra expense on the shell, nominally around 5% of the cost of the house (plus or minus, depending on how fancy the house is), is recouped in relatively few years from lower operating cost, then keeps paying off like a slot machine.
My own house (mentioned in post 14 on this thread, above), is close to 4000 sqft of conditioned space, but based on electric bills costs roughly $600/heating season to keep comfortable with the geo system. As I said earlier, the heat pump uses one well, somewhat oversized for the two-ton heating system that itself is slightly oversized for the job is has to do. It's way oversized, by a factor of at least two, for summer A/C. The area distributor for the geo unit installed, plus two other installers, all wanted to install a five-ton system, based on their calculations, none of which really took into account the special nature of the house. I selected the unit size, and determined how deep the water well had to be, based on my own calculations for the structure. I was right, and they clearly were wrong.
Whether it's design of the shell to be superinsulated or design of a geothermal heating system, there are some contractors in either field who don't really know how to get it right. Anyone having a house built these days and who wants to get it done right really needs to do a lot of homework to understand what goes into either making the house very energy efficient or, in the case of geo heat, how a system is sized properly. Knowing what has to be done on either is an essential part of contractor selection, in my mind.