Geothermal power for your home

volcano.jpgMalcolm Gladwell tells us that geothermal energy isn’t as exotic as we think. His own father recently started using geothermal energy to heat and cool his home. The conversion allowed him to throw away his old oil-fueled furnace — despite living in chilly Ontario.

Like Gladwell, I had assumed that geothermal was useful only in unusual circumstances. Say, if you happened to live in a volcanically active region, or near a body of water with a steep thermocline. It turns out all you need is a decently sized back yard.

Six feet down, the earth stays a constant and comfortable temperature — between 50° and 60° all year round. By burying some water pipes and then running the fluid through a heat exchanger, you can produce ambient air that warms you in the winter and cools you in the summer.

It’s a little more complicated than that. Because humans like it around 70° in the winter, a compressor is needed to bring the temperature of the air up a bit. But the net energy and cost savings are still considerable.

And the system has ancillary benefits. The Gladwells had never had air conditioning before, even though Ontario can suffer through the same summer heat waves as the rest of the North America. And the air quality in the house has improved, because the furnace is no longer sucking up oxygen.

Most remarkable, perhaps, is how simple it is tap geothermal energy:

I think it is also worth noting how absurdly low-tech the system is. It is pvc pipes and a compressor. My father lives in Ontario, where the winters can be vicious, and has thrown out his furnace! …One of the frustrating things about the current discussion over our dependence on imported oil is the persistent notion that real solutions will require some future technological breakthrough. I think we have a lot of the answers. We just haven’t made consumers and public officials aware of them.

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  1. Tina - August 16, 2006

    What a coincidence! I am getting quotes right now to convert over to geothermal–it is extremely expensive here, though, and I doubt I’ll be able to afford it–quotes range from $14,000 to $25,000–but it just reinforces the point at the end of this article–all the technology we need to get off of fossil fuels already exists. What we need is some political leaders with the will to do it. In PA, there are no incentives, tax breaks, grants, NOTHING to help offset this cost (although I hope our Gov. Ed Rendell will do something next term–after all he IS on the Apollo Alliance board so it’s not like he’s uninterested in the environment)
    I hope that the cost has come down by the time I need to replace my furnace!

  2. Flashdaddy - August 16, 2006

    Other pluses for geothermal heat pumps:

    1) They often qualify for reduced rate electricity in late fall to early spring.

    2) Electric ultilities often have low interest financing for the system and installation.

    3) Buy green certificates (gasp, er I mean Terra Passes) and you are of completely renewable.

    4) The warantees on the systems are often longer than conventional sytems.

    5) No box outside for someone to steal (a recent phenomenon, given the high scrap price of copper)

  3. Anonymous - August 16, 2006

    Know of any good contractors in the New England area?
    The one I called also quoted something in the 30,000 range – which makes it completely outside my budget.
    We actually keep our house around 60 during the winter anyway – so maybe there would be a lower cost installation possible?

  4. olive - August 16, 2006

    geothermal can be great but it seems that the expense of installing the system can be a burden. a friend who worked for the DOE was frustrated by the lack of gov. interest in geothermal (as oppossed to wind projects, we surmissed it was because there is not a real delivery system, so once your individual system is installed you are part way off the grid ..

  5. DR Cameron - August 16, 2006

    Please remember the water you use is fresh groundwater,
    the supply is limited.
    you could be using your future drinking water for heat&cooling.

  6. Anonymous - August 16, 2006

    As I read the article, you aren’t consuming an endless supply of groundwater, but rather pumping water through a closed loop, with one end of that loop burried in the back-yard. And if thats not how these systems work, then clearly they werent’ though through very well… I can’t imagine that to be the case.

  7. jlhorner - August 16, 2006

    Does any one know if the ground around the pipes tend to cool off in the winter (and warm up in the summer), giving you diminishing returns, until the season reverses?

  8. Adam Stein - August 16, 2006

    DR Cameron —
    As noted by others, the water is in a closed loop. This system doesn’t affect the water supply.
    jlhorner —
    I don’t have a definitive answer, but my strong suspicion is that there isn’t a problem here. The earth is extremely large, and therefore stores an extremely large amount of heat energy. My guess is that once you get a few feet down, the seasons are too short to budget the accumulated heat energy much in either direction.
    All —
    It’s true there’s a large up-front cost for geothermal, but the payback period seems pretty good. Something to think about.

  9. Alex Stange - August 16, 2006

    Wow! Why does this sytem cost so much? When I think low-tech and simple, I think cheap. Do they have to dig up your whole yard and install hundreds of feet of PVC pipe? Is the pump very expensive?
    For 15k – 30k it sure seems like there would be higher-impact things you could do to reduce your footprint. Find a friend who drives 20 miles to work every day in an SUV and buy them a Civic hybrid for 22k!

  10. veektor - August 16, 2006

    -Now that you have whetted our appetites and curiosity about geothermal … how about some links or some further information for those who wish to pursue it further?
    -We visited Iceland a few years ago and were astonished how omnipresent closed-system geothermal energy was, so it is certainly a viable process and the technology exists. Even the average home had geothermal, although they have a large and experienced market (I heard some things about corrosion and valving which might be kind of an unknown factor for contractors here in the US housing market). Perhaps someone in Iceland can furnish us some information.

  11. Anonymous - August 16, 2006

    I believe the link to the original story (with more of the technical details) is:

  12. Adam Stein - August 16, 2006

    Alex and veektor —
    See a discussion of the financial implications of geothermal here, along with some links to additional resources.

  13. Mindyleigh - January 24, 2007

    How much of the work could a DIYer do in the process of geothermal, to offset the overall cost? Is this practical in Texas, with it’s shale crust?

  14. Adam Stein - January 24, 2007

    Good questions, Mindyleigh. You’re definitely best off consulting with a professional for details related to your own home and geographic area.

  15. Anonymous - February 5, 2007

    I have geothermal and its 55 degress in the house. My advise, doen,t do it.

  16. Leemer - February 7, 2007

    The ones used here in Missouri are closed loop systems.

  17. Anonymous - April 18, 2007

    Here’s a thought: You can’t lower a home’s carbon footprint with geothermal in more northern latitudes, i.e 42 N. Besides the energy needed for the compressors, a lot of electricity is required to circulate such a small amount of heat generated requireing a large volume duct system and a big fan to push through the duct. The 2/3 loss of electricity from the generating plant to your home, negates the 1/3 lower footprint on your end.
    Comments anyone.

  18. Anonymous - April 25, 2007

    Geothermal is often best used in conjunction with radiant in floor heating. the only electricity used is in the circulating pumps for the closed loop system and the pumps for the radiant heat.
    My brother has used this combination for the past 12 years and is thrilled with the results. He also uses an air exchanger and cools or heat the air used in that process, it also generates hot water for domestic use. If he had to have air conditioning for much of the year that could be a differnt story but since he lives in Canada, not as much a problem.
    He has more that paid back his initial investment. Yes it is more expensive to start but with the changes in the price of fuel, the payback period is getting shorter and shorter.
    My next home will have one.

  19. Anonymous - May 31, 2007

    Yes another disatified Pennsylavania resident. Govenor Rendell needs to go he is NO friend of the environment. He is only a mouthpiece for the media we need real change in Pa. We should be leading the nation but no he does not care. We can corner the industry up here and manufacture geo systems and install them in the Northeast but NO Govenor Rendell does not give a darn

  20. Steve G - June 8, 2007

    I owe a plumbing,heating & airconditioning company and am building a 15,000 sq ft. house with inside pool. I am looking for a experienced geohermal designer of a custom house with heat pumps for hot water heating. Thanks Much

  21. Sara Kerby - April 7, 2008

    I am super interested in this geothermal thing. How can we kick start it in our city (I live in Wilmington DE) and are programs for promoting this in states or cities out there? I need information on benefits, pros and cons of it, and stats on what kind of savings we are looking at. Thank you for anything you can send me on this topic.

  22. Valerie Pasco - May 6, 2008

    If you want to know more about it, you can look on this website how it works and what is done in Europe. Just for information, I don’t have any interest in this company. I just like it because the system is very well explained.

  23. Darlene - July 23, 2008

    I feel that if the Government is sincere in wanting to help the public with energy, they would put geothermal energy in homes for free if people want them so there is less burden on the usage of oil for home heating. Even if out government were to give a person a grant to install one, we would certainly put one in our home….we would love to help keep the glaciers from melting but can’t afford the up front cost of the unit and our income is so low we really can’t afford payments on one either. Being over 60 I don’t know as if a geothermal unit would pay for itself by the time we died. Any advice? We live in Northern Wisconsin and it gets very cold here and gas and fuel are staggering, even with energy assistance we have to practiaclly freeze to keep the cost down…..thanks for this opportunity to learn more about thermo energy…

  24. Anonymous - January 16, 2009

    i live in nova scotia canada
    installed geothermal closed loop
    system in our home 150+yrs old 4100
    sq ft current temp 2 pm jan 16th /09 the house is a balmy 70F
    last night temp was close to -40 expected overnight for tonight & sat -41 temp remains steady at 70f

  25. dave in kentucky - March 1, 2009

    Geo (closed loop or open using the aquafier) is probably going to be way more used than the sluggish hvac contractor base will like. Paybacks are better than over complicated conventional configurations. Sure they’re not for every situation, but it will surprise people how many applications are possible. Location can be a killer but not always. Maybe the public is not aware that Obama signed the stimulus and the fall bailout included renewable portions that now have a 30% credit off of your fed tax bill- not adjusting your income- money back- it rolls over- match that- it’s unlimited, too.
    Steve G. keep looking for your contractor, every year more of us are seeing the light.
    Anyone with a geo system and his house is 55 degrees, is silly, gullible or doing business with a hypnotic snake. The pipes are in the opposite temperature mode of operation- they dispel heat to the ground to cool the house and vice-versa, cool the pipes while they are absorbing heat to put into the house. The compressor uses electricity to move this heat, hence the COP
    (coefficient of performance) of up to 5! Try to get that out of any other systems. We use mostly closed loop, with a few open loops that put the water back after use, without any chemicals etc or other contamination. Look at the whole energy consumption picture and buildings houses etc are real real big. We need to work on this segment as much as cars. Reduce generating needs, buy geo if you can. Your car circulates water and anti-freeze, so what’s new about that? There have been water, gas, electric and many other pipes underground for a long time, why were they not a big deal?

  26. Mark - March 12, 2009

    Thinking of some additions to our former cottage turned home…we have a 6 inch 400 foot deep well that is now our drinking water source….would it just be simpler to put the pipe (closed loop) inside it. Dual purpose well would provide drinking water/hot water/heat. It is my understanding a closed loop system can do this. Has anybody in Canada done this and what was the cost..I am relying on info from Bassfeld Technology Transfer website page 7 Geothermal Power Generation sq footage of home with addition is just 1100 sq feet.

  27. dave in kentucky - March 12, 2009

    Mark, I tried one alot of years ago and did not have near enough well capacity. Some rules of thumb that we see in Kentucky: closed loop- 175-200′ per ton ( 3/4″ drop pipe), 250-300’1.5-2 tons ( 1″ drop pipe),
    350-400’+ probably 3-4 tons ( I say probably because most designs with deep wells are commercial and they always run software with some soil/rock input, and sometimes even a test well for thermal conductivity and diffusivity. One 400′ well would be low for the 1,000 sq.ft. heat load. Also, you would lose the volume of the 1.25″ drop pipe associated with a 400′ deep geo closed loop application. Good Luck.

  28. Kevin Meadows - August 25, 2009

    Would you please send me the information or a link as to converting to Geo for my personal home? And anything else that you think I should read or educate myself on.
    I am building a new home and I want to use every material and install every known piece of equipment possible to make my home 100% energy efficient and self reliant.