A Cheap, Non-Polluting Heat Source? You’re Standing On It

winter house

What’s the cheapest, greenest heat alternative for a house, other than building it from the ground up for passive solar? Natural gas? Well, that’s cheaper and less dirty than oil, but no, definitely not. Wood pellets? Better, but they still require fossil fuel energy to manufacture. Cord wood? You’re getting warmer. Geothermal? Yes.

Your question about geothermal heat may be the same as mine was: how in the world are we supposed to get heat out of the ground? Doesn’t that require geysers or something? (OK, your question may not be as ignorant as mine was.) The answer is that no, there are no geysers involved. Here’s the thing: wherever you are in the world, if you dig down a bit below the frost line–say, around ten feet down–the earth is a constant 54 degrees Fahrenheit. Geothermal heating exchanges fluid in pipes between your house and that area underground to bring up the relative warmth.

Of course, 54 degree-fluid isn’t going to do much to thaw out your freezing toes on a cold day, but using a fairly efficient electrical condenser similar to what your refrigerator uses to create cold, a geothermal heating system can boost that temperature to be used as an efficient heating source for a home. How efficient? In the last few years, geothermal systems have improved to the point that modern ones use only about a third as much energy (to pump the fluid and run the condensers) as propane.

Here’s a video on how this works, though keep in mind that there are different kinds of geothermal heating systems

Not sold on geothermal yet? Well, did I mention that it also works as extremely cheap air conditioning, using the same apparatus and principles? And if you’re interested in going very, very green, you can generate some or all of the electricity used to run the pump and condenser with wind, solar, or another renewable source, which brings your non-renewable energy usage for heating and cooling down to nothing at all, as long as your electricity source can keep up. Contrast this with direct electric heat, which is pretty much the least efficient and usually most polluting heat source you could have.

Oh, and did I mention that the Federal government offers a 30% tax credit (that’s not a deduction–that’s a credit, i.e., money in your pocket) on qualifying geothermal systems?

So why isn’t everyone rushing out and getting geothermal heat? Unfortunately, these systems cost real money to install–apparently $20,000 is a good ballpark for a modest single-family home. Keep in mind that the government will pay 30% of that, which to my mind is a very sensible way to start addressing a very large part of the climate change problem (home heating). Even with that, though, it may take a decade for the system to pay for itself–yet in the long run, the cost savings are enormous, and of course the value of your home (if you own one) goes way up. Geothermal will also get cheaper and cheaper in comparison to almost all other options if over the coming years the price of fossil fuels goes up … which frankly seems more or less inevitable to me (more regulated + more rare = more expensive).

There was a good article on geothermal heating recently in my local electric co-op’s newsletter, although a piece elsewhere in the newsletter on the proposed wind power moratorium in Vermont is disturbingly complacent and ill-considered. (You can probably guess where I come down on that issue.)

Have any information or opinions pro or con on geothermal heat pumps? Please comment!

Photo by Denis Collette…!!!