byBillMay 9, 2004

My favorite renewable is geo-thermal. I just read a post

in the heat and air/conditioning section that asked about geo----every responce was positive. It really is the best renewable available to the new home builder. Solar costs too much, wind is impossible---but using the 55 degree temperature of the earth for heat, a/c and domestic hot water is not only possible it is the right way to go. No outdoor equipment to be vandalized, no maintenance for years, no emissions into the atmosphere, no carbon monoxide emissions to jeopardize the health and welfare of the household. I call it a process of elimination---no chimney, no outdoor equipment, no maintenance contract, no problems.

Geothermal pays for itself in a short time and if you talk to the right people at the bank you can get a larger mortgage or a lower mortgage rate for using such a great energy saving system.

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Geothermal is something of an energy cheat, it uses electrcity to move heat from the ground in to the building, rather than generate heat with elecrical elements. On the good side this uses far less electrcity, but it's still electrcity that is predominantly generated with fossil fuels.

Geothermal energy may be renewable in the sense that the heat in the earth will not run out, but we still need some extra electrcity to extract it. Unless this electrcity is made from renewable sources, I don't feel geothermal is renewable energy.

Still, it's reliable, cheap to use and has a minimal environmental impact. I wish I could install it in my house. The initial installation cost isn't so bad either, not when you compaire it to the cost of a new furnace *and* air conditioner together.

    Bookmark   May 12, 2004 at 9:55AM
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Bry----the geo system uses about the same amount of electricity as a refrigerator does. No one would think of doing without a fridge. The geo makes clean heat, no combustion, no carbon monoxide, all the a/c and almost all the hot water a home can use. Hook it up to a photovoltaic system and you've got it made. No oil, no gas, no coal from NewCastle, and just a tiny bit of electricity. Removes humidity at the same time as it a/c's so you save on that little item too. Shut off the telly for a hour and you could pay for the healthiest, cleanest heating and cooling system in the world. Hook it up to radiant heating and be comfortable, man, no scorched air full of dust and varments to contend with.

Bry according to our EPA (environmental protection agency)it is the best system available to man. Buildings use 50% of all energy, vehicles 25%-------so cutting building energy in 1/2 would be the equivilant of removing every vehicle from the road. Build buildings correctly and save the world !!!!!! Cheer-o, pip-pip and all that rot (heard that in an English flick, which will be nameless).


    Bookmark   May 15, 2004 at 7:40AM
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The amount of electricty used is very dependant on the climate you live in. I looked into the possibility of geo in central Albera, Canada, where the climate is significantly colder than most US states. The loads needed for the heat pump were 240 V @ 35 amp, which is roughly 8.5 KW. Show me a fridge with that kind of load. I know of people that have geo systems in this area and I asked then how much they run during the -40 snaps that show up every winter, they all said 24/7 when it is that cold. We are talking roughly 200 kwh's per day.

Geo is very good choice in mild climates where heat & ac are standard, but in more extreme climates where most people only worry about heat, a high efficency ng boiler/furnace is still a better option, especially when elctricty is still made from buring coal.

    Bookmark   June 2, 2004 at 5:01PM
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In SE Michigan where I live we have cold winters with many days 0 to -5 F. Definitely not as cold as Alberta. But the lousy unhealthy wet chilling air in this water logged state has us running our furnaces constantly. I have met many people from other parts of the country who comment on the way this state feels colder than Alaska because of the wet chill. People who install geothermal here save money over electric, and propane. It used to be a break even with natural gas but the cheap natural gas is coming to an end here too. It is true that the electric needed comes from burning coal or oil. However it is also true here that the homeowners are having greatly reduced fuel bills which is lifesaving for them if they can roll the geothermal cost into the mortgage

Here is a link that might be useful: Glenn Haege on geothermal in Michigan

    Bookmark   June 3, 2004 at 9:16AM
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Yes, I agree completely. I consider Michigan (0 to -5) mild ;-), altho most would not. If I was located in that area, ground source heat pump would be my choice. My only concern witht the comment Bill made was analogy to the fridge load.


    Bookmark   June 3, 2004 at 12:00PM
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Does anyone here have geo-thermal? We are almost at the groundbreaking stage and I wonder if we are too late to install one in. I had called someone locally and they quote me a price of around $7,000 to dig for a 5-6 ton unit? (I am not sure if I am using the right terminology or making any sense at all).

Is this reasonable? I do not have much of a good concept for geo thermal but would like to know more about it. My husband really would like to have one but does not think the builder might want to go with it.

Also, to byBill, are banks still giving out lower mortgage rates to people who are installing them when they are building their house? Is this a local thing or do all banks do this? I have not heard of this before...would like to know more.

Thanks for any input!

    Bookmark   May 3, 2006 at 11:03PM
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I know there is a lot of enthusiasm for geothermal, but personally, I'm not so convinced its a very good choice, particularly from a greenhouse gas point of view.

If you compare a geothermal system with a COP of 3 to a 90% efficient natural gas furnace, which generates the most greenhouse gas?

If you look at how much greenhouse gas is generated to supply 100,000 BTU of heating to the house:

The geothermal heat pump expends this much electricity to deliver 100K BTU to the house:
KWhrs = (100000 BTU)/((3412 BTU/kwh)(3COP)) = 9.76 kwh

According to the GH calculator at:
The coal fired plant that provides the 9.76 kwh of electricity will put out 19.5 lbs of carbon dioxide.

The natural gas furnace will burn this much gas to deliver the same 100000 BTU to the house:
Therms of gas = (100000BTU)/((100000BTU/therm)(0.9 efic))
= 1.11 therm of gas

Using the same carbon calculator as above, this 1.1 therm will generate 13.2 lbs of carbon dioxide.

So, it appears to me, that the geothermal heat pump actually puts out more greenhouse gas in delivering an identical amount of heat to the house??

On a cost basis, where I live, the 1.11 therms of gas (at $1.20 per therm) would cost about $1.33, and the 9.76kwh (at $0.12/kwh) would cost about $1.17, but this depends very much on where you live.

I'd like to be wrong about this, since we need all the good alternatives we can get, so if you see an error in the above analysis I'd like to hear about it.

To me, an alternative to a geothermal heat pump would be to spend the extra money that would go into the heat pump on better insulation, more infiltration control, and better windows. And, if you have the site for it, on a solar thermal system to supplement your regular heating. These measures will definitely save you money and reduce greenhouse gas emissions.

Just my 2 cents,


    Bookmark   May 4, 2006 at 7:12PM
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Coupled with the fact that Geothermal heat pumps cost 2X the price on conventual system I am having a hard time justifying one - even though I can use pond loop.

Solar with evacuation tubes and radiant heat is hard to beat from an expense standpoint.

    Bookmark   May 5, 2006 at 3:54PM
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Re: Chief18

Sorry to say, but your information is erroneous. Geothermal is making big inroads in Alberta and is growth industry in your province. This was abundantly clear by the astonishing number of drillers who had traveled east to Montreal from Alberta to train in the installation of geothermal systems. Were this technology not viable in colder climates, these drillers would not leave their drill rigs idle to travel thousands of miles at their own great expense!

Re: cookingpassion:

$7000.00 to drill and install a vertical borehole system, fill it with antifreeze, bring it in to the heat pump and pressurize it would be a very reasonable price where I live (Montreal Canada) for a 6-ton system. To be sure, seek other quotes and ask specifically what the price includes and does not include. However, it is unclear from your post (digÂ) as to whether this quote is for a vertical system or some variety of a horizontal system.

Find an installer in your area who is IGSHPA accredited or certified. This will more likely result in your choosing a competent installer.

Your builder will Âgo for it if thatÂs what you specify. It is your home after all; besides, once the ground loop is connected to the heat pump, the rest of the system is EXACTLY the same as for a conventional heat pump with regards to heating and air-conditioning. As regarding first costs of a system, there wonÂt be a huge difference to install geothermal. ItÂs basically the cost of the ground loop.

Regarding GaryÂs comments. I wonÂt dispute them. IÂm sure theyÂre well thought out; IÂve never doubted his integrity or sincerity  and still donÂt! However, I would like to say this.

We live in Montreal Canada. ItÂs quite cold here in the winter, often VERY cold. ItÂs also often surprising hot and humid in the summer for this northern a location. We have been using geothermal for a few years now (3 heating seasons). I have spoken with many people, many skeptics, many naysayer, and many bean counters (WhereÂs the pay-off? WhenÂs the payback!). I have yet to meet ANYONE with a similar size home that is heating it for ANYTHING close to what itÂs costing us  especially after the energy price increases weÂve experienced this past winter!

ThatÂs the bottom line.


    Bookmark   May 5, 2006 at 5:12PM
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That may be the case up North but down here in the MD/VA there is not enough competition to bring prices down. Certified installers are charging very high prices because they can get away with it. If you read the past posts the net difference for a geothermal is $15-20K higher on average. I had one installer almost "brag" that it would cost between $40-120K where $40k is an "entry level" system. Another mech contractor told me that companies went into the geothermal business for higher profit margins and to work with accounts "in the upper income bracket" We need more competition!

$7K is an amazing price for the loop system including digging the trench, piping, and setup. I am not giving up on my potential pond loop until I get all my quotes back. I may even attempt a DIY job for the piping if I can save $10K.

    Bookmark   May 5, 2006 at 5:52PM
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I am waiting for a company that does residential geothermal to send me a brochure on what they do. They are the one who quoted me the $7,000 price plus whatever the cost of the heat pump.

What is the difference between a vertical vs. horizontal system and I read somewhere on this forum about copper pipes and plastic pipes? We are about to break ground next week or so and I wonder if we still have time to install the geothermal system. Exactly when does a system get installed? Sorry to ask so many questions, I really don't know too much about this...just know that my husband really wants one since solar panels would probably not be allowed in our new subdivision :(

    Bookmark   May 5, 2006 at 7:03PM
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You can either drill down or horizontally to run your water loop. Most people with land dig horizontal trenches 6-8 ft down - less expensive that way. I have a pond nearby so I plan to run loops though the water.

The question of when depends on your builder and site conditions. I am still deciding which way to go while my framers are constructing the first floor. You need to plan where the loops will run and enter the house as to not interfer with the rest of your utilities. The layout of your duct work should go in after framing. The selection of a heatpump, system sizing, etc. should drive your duct design. Hope this helps

    Bookmark   May 5, 2006 at 7:27PM
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Re: rychnc

"I have a pond nearby so I plan to run loops though the water."

If you have a suitable pond to run your loops in youve got it made! This is probably the least expensive way to do geothermal, no drilling (except through your foundation wall), minimal trenching. Whats to think about (providing its permitted)?

Re: cookingpassion

Geothermal systems using copper tubing in the ground loop are called DX or Direct Exchange systems and run the refrigerant through the copper tubing in direct contact with the ground.

Theyre great systems providing your ground is ph neutral. Regular systems use high-density polypropylene pipes in the ground circulating some kind of antifreeze. This necessitates the use of an additional heat exchanger and a circulating pump as well as boreholes being about 40% deeper and twice the diameter resulting in higher drilling cost.

We have a DX system; never had a problem with the boreholes GREAT SYSTEM! However, I always play it again in my mind, were we to it again, would we go DX? Im really not sure. Both systems have their advantages. I would probably go for conventional only for peace of mind and to distance myself from this whole controversy. My wife on the other hand, who is a supremely intelligent and knowledgeable lady says, Look, we know the ground is ph neutral; since when have we ever had a problem with the tubing in back of a fridge?

Thats the simplified version. Its a tough call especially for an IGSHPA accredited installer.


I can no longer find the link on the site to this interesting fact sheet about copper, so Ill just copy and paste. Its rather long, I apologize. Breeze though it if you like.

About Copper

What's Your Best Buy Today? Copper or Plastic?

When comparing geothermal systems, compare the value and benefits of copper compared to the plastic pipe used in water source geothermal systems.

No heating and cooling piping product is totally immune to all problems. However, for more than 60 years copper-based products have continually proved themselves to be the most robust and reliable for all kinds of heating and cooling systems. There was a time when we were limited to a relatively small range of basic materials from which to make things: wood, stone, iron, brick, leather, cotton, wool, and of course, copper. Copper is man's first, and still most indestructible
non-precious metal.

Because copper withstands corrosive elements better than any other engineered metal, it long ago set the standard for plumbing systems. The 1940s fostered the Age of Synthetics, an era of technological change. It was the natural outgrowth of an economic system that stressed mass production and sought substitute materials which would do the same job for less money. Manufacturers looked at plastic for a wide range of building products-especially plumbing. Lower first cost, rather than long term reliability, was the driving force.

Recently, however, we have seen a growing reaction to this "throw away" economy. Consumers realized that the "cheapest" was not necessarily the least costly in the long run. In many cases, they found that some of the old, basic materials are still the best, still the most economical, because they last and give years of reliable trouble-free service.

Copper or Plastic?

Here's why generations of homeowners and professionals in the building community feel copper is the best and most economical material:

* Copper plumbing has a 60-year track record of nationwide acceptance for water, waste and space conditioning use.

* Rigid standards govern the composition and properties of copper products for specific applications. And all products can be tested to ensure conformance to these standards.

* Precision and control in manufacturing assures a quality product and long service life.

* Copper tube products have permanent product identifications, including type size manufacturer and country of origin. You know what you're installing. Inspectors and owners know what's been installed. The manufacturer backs up the product.

* Nationwide, codes and standards assure reliable installations.

* Refrigeration contractors have more than a half century of know-how, experience and customer satisfaction with copper tube and fittings.

* Copper systems can be installed, tested and used year-round at any temperature in any climate.

* Copper systems can be tested immediately after installation.

* Copper is not damaged by either near-freezing or boiling water temperatures.

* Copper requires virtually no maintenance and can be protected more easily from damage than plastic.

* Copper's superior thermal conductivity provides superior heat transfer.

* Copper can be stored or used anywhere, indoors or outdoors, without harm or deterioration by the sun's ultraviolet rays or other weather elements.

* Copper is non-flammable. Unlike plastics, it doesn't burn or melt or support combustion. It maintains pressure even when subjected to flames.

* Copper will not "pipe" flame through walls or floors. It does not violate the integrity of fire blocking.

* Copper plumbing products do not give off toxic gases when exposed to fire.

* Copper tube is rigid, requires fewer supports, and does not sag over long runs. Copper, unlike plastic, will not fail from the "rubbing" or abrasion normally encountered in service.

* Copper tube is flexible (whether it's hard-drawn or annealed) and has a smooth "polished" interior - which means it's easily installed anywhere and will not impede the flow of refrigerant.

* Copper silver soldering is a safe, reliable and non-toxic operation.

* Copper is fatigue resistant. Copper systems do not present the problems associated with excessive and repeated contraction caused by extremes in temperature. Well-installed copper joints are for keeps, they will not break down or pull apart.

* Copper scrap has a high value when sold for recycling. It ecologically friendly.

* Copper does not rely on domestic or foreign oil production for its manufacture.

* Copper tube is all natural. No synthetics are introduced or used in its manufacture. It is environmentally friendly.

* Copper is a noble metal combining extraordinary corrosion-resistance and high strength for refrigeration piping applications.

* Copper tube and fittings can, if necessary, be disassembled and reused.

* Copper plumbing, like copper wiring, has recognized quality and value that helps sell (or resell) your home or building.

* Copper plumbing protects your home investment. It's an insurance that pays dividends year after year after year.

* Many decades of in-service experience have proved copper's reliability. It will outlast the life of the mortgage.

* Copper systems are the worldwide refrigeration standard of excellence.

* Copper has eight times the thermal conductivity of other metals and is the material of choice for high performance, high efficiency heating and cooling systems. Due to its high performance characteristics, copper is the material of choice for American Geothermal(R) DX direct exchange geothermal heat pumps.

* In the United States, nearly 50 percent of the copper used each year comes from recycled sources. Copper is one of the most highly recycled materials and can be used over and over again, helping to preserve natural resources and the environment.

* Copper plumbing products offer unbeatable quality and value.

* Copper tubes and joints are strong. They can withstand pressure surges and rapid temperature changes without rupturing.

* Copper plumbing lasts. Copper doesn't become brittle with age. Once installed, it stays installed.

* Copper is an investment. When the time comes to sell your home, the quality of copper refrigeration piping and plumbing can actually enhance its resale value. Copper is the right choice no matter where you live. It meets or exceeds all standard refrigeration and plumbing codes in all 50 states.

* Decades of successful service say, "You can trust copper."

For more information on the value, benefits and technology advances of copper visit the Copper Development Association web site at

    Bookmark   May 9, 2006 at 12:10PM
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I am fascinated by combining ground source heat pumps with solar electric for the zero energy home. Here is a white paper I wrote on the topic recently.

I too wonder, how do we heat urban homes with out natural gas... this could work.


    Bookmark   May 11, 2006 at 6:07PM
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Re: solar niels

I too wonder, how do we heat urban homes with out natural gas... this could work.

GSHPs, masonry heaters, and solar energy are the answer. The problem is that most people would sooner spend their money on sexier things that show, such as larger homes, bigger fancier kitchens & bathrooms etc.

That said, we all have the right to define our own needs and priorities.

BTW: Read your paper; an interesting read.


    Bookmark   May 15, 2006 at 4:22PM
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I am just about to start a gut-renovation of my house in Boston.I am considering a geothermal system with radiant floor distribution. As part of the project we need to excavate the basement floor 2 feet down and pour a new concrete slab. Does anyone know if the tubing could be installed under the basement slab? The basement floor will be about 5 feet from the ground.Would PEX or cooper tubing be best?

    Bookmark   June 3, 2006 at 11:00PM
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