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Do Geothermal Heat Pumps Have Mainstream Potential?

Published: February 27, 2007

What is your opinion of ground source heat pumps, do you think they have what it takes to make it mainstream in American homes? -- Bryan Long, Port Hueneme, CA

Today, geothermal heat pump (sometimes referred to as ground source, GeoExchange, earth-coupled, or water-source heat pump) installations are increasing by double digits. Before I answer your question specifically, let me tell you a little about geothermal heat pumps (GHPs) in general. GHPs represent one of three types of geothermal technology. The first is electricity production from high temperature resources; the second is "direct use," which utilizes lower temperature resources for a number of applications, including home heating, aquaculture regulation, agriculture, and industrial purposes. The third use -- GHP -- is an electrically powered system that uses the earth's relatively constant temperature to provide heating, cooling and hot water for homes and commercial buildings. GHP has been in use since the late 1940s. According to the Ground Source Heat Pump Association (GSHPA), GHPs circulate water or antifreeze solution through plastic pipes buried beneath the earth's surface. During the winter, the fluid collects heat from the earth and carries it through the system and into the building. During the summer, the system reverses itself to cool the building by pulling heat from the building, carrying it through the system and placing it in the ground. This process creates free hot water in the summer and delivers substantial hot water savings in the winter. GHPs have definite mainstream potential. GHPs have the capability to be used anywhere in the country -- and, in fact, they're used in every U.S. state and several outside countries. Current data shows continued growth across all market sectors. Over the past few years, as oil and gas prices have soared, GHP sales have increased annually from 22 to upwards of 50 percent. Still, GHPs have significant untapped potential. The U.S. General Accounting Office estimates that if GHPs were installed nationwide, they could save several billion dollars in annual energy costs and substantially reduce pollution. Although GHP systems cost more upfront than conventional systems, investments can be recouped in as little as three years, according to GSHPA. In fact, GHPs are one of the most energy-efficient, environmentally clean, and cost-effective space conditioning systems available, according to the EPA. Geothermal heat pumps can reduce energy consumption -- and corresponding emissions -- up to 44 percent compared to air-source heat pumps and up to 72 percent compared to electric resistance heating with standard air-conditioning equipment. GHPs generate no on site emissions and have the lowest emissions among all heating and cooling technologies. Your decision to install a GHP is an environmentally conscious choice. The link below provides more information about GHP and the incentives available for installation. 26 states now offer incentives for geothermal heat pumps. Additionally, the federal government offers a $300 dollar incentive for heat pump installations. Stronger federal incentives to reduce the upfront cost to consumers and businesses, as well as support for improving information, training and related market development could help accelerate their deployment. Today, GHPs could be retrofitted to almost any house or school in the country. This would go a long way toward reducing pollution -- every 100,000 homes with geothermal heat pump systems reduce foreign oil consumption by 2.15 million barrels annually and reduce electricity consumption by 799 million kilowatt hours annually. As people consider the long-term impacts of their choices -- both environmentally and financially -- I have no doubt that GHPs will become mainstream.
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Comment
1 of 30
February 27, 2007
I have some experience with ground coupled heat pumps. My impression is that it definitely has potential, but the systems are still not well understood by the general public, causing a backlash when they encounter the trade-offs.

Ground coupled heat pumps have a very high initial cost and require a fair amount of land to implement. In addition, the heating and cooling must be balanced for long term viability, since the earth is basically used as a thermal battery.

This system is very efficient and should have a long term payback. Some novel financing schemes may be in order. A drilling company in northern Ohio (I don't remember the name) sets up a well field for institutions and charges the institution like a utility for the energy transferred.
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2 of 30
February 27, 2007
This article appears to be missing information on the obstacles to widespread use. Is it just a consumer information thing?
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3 of 30
February 28, 2007
It seems like this is the only place where I find educated discussion anymore. That said, there is huge incentive for commercial applications, from small hotels to large casinos for example. There is a geoxchange program that pays for all the commercial upfront costs for installing geo. For example, if a new bldg has budgeted say 20% of it's construction project for hvac/mechanical install, we will take that figure out of their budget, install the geo system (entirely) spread that costs over 20 years and allow the energy savings to pay for it, and save 30-60 % on the energy bills. Tax credits/savings on top of that makes these decisions quite easier to make, it's quite difficult to turn it down frankly.If anyone has an interest in this incentive, I'll be glad to help.
Regards,
Brian Mello goldeneaglefund@cox.net
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4 of 30
February 28, 2007
Being an HVAC engineer, I can say that building owners have a very strong bias to minimizing first cost over life cycle cost. This is especially the case with systems which are hidden, such as the HVAC systems. Don't underestimate this hurdle.
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5 of 30
February 28, 2007
I recently built a house in Ca. and was ready to use a GHP HVAC system. What I found was to install a GHP HVAC for a 4500 sq. ft. house was $25/sq. ft. or $90,000. This compared to about $30,00 for a standard system. (2005 pricing probably higher now)

The boring costs to do a vertical system was what was proposed. I was assured that a a horizontal system would be more because it requires trenching of 6 ft. Though that doesn't sound like a deep trench, OSHA requires trenches of over 5 ft. be shored up for safety reasons. So while it sounds very simple, as Terry stated above, to lay the PEX in a trench, if you have a contractor do it to code and follow OSHA regulations, it is going to be very expensive for the trenching because of the additional cost of shoring the trench.

In short, I agree with everyone who discussed the technical benefit of the technology, but they will not go mainstream unless there is a more economical method of deployment.
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6 of 30
February 28, 2007
Can anyone tell me the "sensitivity" of a heat pump system ROI to electricity rates given the electrical load needed to run the compressors, pumps etc.. In the Northeast the return diminishes alot with our the higher 15 cents kwh) electricity costs doesn't it (as compared with Illinois 8 cents kwh)? Also when one considers the inefficient manner (coal fired elec sources and distribution losses)to supply the electricity to a home for geothermal doesn't it hurt the environmental value of GSHPs. Compare this with efficient on-site gas fired heat source- on a released CO2 quantity per btu of heat delivered to the home. Anyone know?
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7 of 30
February 28, 2007
You can save 65 - 75% of your heating costs
All around us are sources of energy in the form of stored solar energy, which even if they have a low temperature can provide us with heat. But how can a few degrees above zero gives us energy to heat radiators and hot water. Let us explain!


During the summer, solar heat is stored in the surface layer of the soil. Also down in the bedrock there is a source of heat that stays at practically the same temperature all year round.
With Ground-source Heat Pumps you can use these energy sources.
Giulio Negrini
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8 of 30
February 28, 2007
I can vouch for GRHPs. I've had one since 1985 using vertical and horizontal closed-loop piping. I've just installed by second unit this past fall with a 27 SEER, ozone friendly A410 and a hot water heater supplement. These new GSHP units are amazingly efficient. It recently got down to single digits and the input pipe water was in the 30s, yet the unit was still able to pull out enough heat to blow warm air. The unit is inside, which is one reason why it lasts so long. There is very little maintenance - just change the filter like a normal heat pump.

Yes, it did cost more to install the pipes, but I'm convinced that the GSHP has saved thousands of dollars over the past 22 years, plus reducing tons of greenhouse gas emissions. To top it off, I applied and received a $1,000 grant from the Maryland Energy Administration, and I get a $300 fed tax credit.

I highly recommend GSHPs for a home or business. They save money, energy, and the environment.
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9 of 30
February 28, 2007
IN MY PREVIOUS STATEMENT I FORGOT TO MENTION THAT THIS MIGHT BE A WAY TO GO FOR COMMERCIAL BUILDINGS AS WELL, ALL YOU WOULD HAVE TO DO IS "INCREASE THE COIL LENGHTS OR/AND DIAMETRIC SIZES" UNDERGROUND TO CREATE A LARGER ABSORBTION BASE TO WORK WITH AND ALSO THE DEPTH COULD ALSO BE GREATER TO HELP ARRIVE AT THE BEST SOLUTIONS...
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10 of 30
February 28, 2007
THIS IS FINALLY GETTING TO THE PUBLIC THROUGH AWARD-WINNING NEWSLETTERS SUCH AS THIS ONE!! THERE IS JUST ONE MISTAKE MADE BY THE WRITERS AND THAT IS THIS "UNDERGROUND TECHNOLOGY " HAS BEEN AROUND FOR AT LEAST 100 YEARS PLUS,SOME GROUP DECIDED NOT TO "INFORM THE PUBLIC" OF ITS ADVANTAGES IN HOME COMFORT YEAR ROUND!!I LIVE IN A 3 FLOOR HOME WHICH HAS HAD THIS "GREAT 3-CUBIC FOOT SIZED UNIT ON THE FLOOR AND A "A-SHAPED CONDENSER UNIT{which sits inside the air chamber of the furnace} WORK WONDERS DOWN TO ABOUT 15DEGREES THEN YOU HAVE TO KICK IN YOUR "OTHER" HEAT SOURCE SUCH AS "WOOD BURNER,OIL HEATER,OR ELECTRIC HEAT!! A GROUND THERMO-UNIT FOR 70YRS IS A REAL COST SAVER !!!!!!!!!!!!
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11 of 30
February 28, 2007
Thanks for a very clear article. And especially thanks to John and Terry for providing some anecdotal facts and common sense to the discussion.

Supplemental financing will go a long way toward jump starting this very feasible solution to home heating and cooling. Here in Texas, the barrier is simply that I have found no one who has experience or knowledge of how it works, so no one will get started on it. The typical self-eating watermelon problem. No one wants to be a guinea pig.
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12 of 30
February 28, 2007
Of course GSHP's are a great solution. See comment 8 above from Terry Galloway. An analysis of the potential should be required for all public buildings, and smart commercial and residential builders should offer the calculation too! Long term savings far outweighs the initial cost difference to fossil fuel heat.

Also, check out www.SolarPanel-Rental.com for another concept in savings for your home.
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13 of 30
February 28, 2007
First, thanks for the article! It is about time that GHP's get some notice. When I built my home in Delaware 18 months ago, I installed a vertical closed loop system, with 3 60' wells into the ground aquifer. True, the installation costs are higher than other systems, but the run rates are dramatically lower. And, many states and, I believe the fed, offer grants, rebates or tax relief for alternative systems. Without any of those, I estimate my own break-even point to be about 3 or 4 years. These is a simple, but quite effective, way of lowering heating/cooling costs while being extremely environmental friendly.
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14 of 30
February 28, 2007
Ground Source Heat Pumps do not need a lot of land or expensive drilling. I have had GSHP on my home running for 10 years with 1400 ft of PEX plastic piping in slinky-coils that were placed 6 ft down along with the excavation for the house foundations and retaining walls. It took 1.5 days to lay the coils in with the ditch. Next, a good sand was placed around the coils, then felt cloth and then the soil was put back. It was easy to do, inexpensive, and the glycol system has worked very well heating in winter and air conditioning in summer. The electric motor driving the compressor is like 1/4 h.p. and the glycol circulation pump like 1/8 h.p. Very efficient !

There continues to be misunderstanding on how heat pumps work and how the relatively even ground temperatures some 6 ft down can be used to advantage. Our renewable energy groups should promote GSHP much more.
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15 of 30
February 28, 2007
during a remodel of my house and installation of a PV system, I considered a ground source heat pump to drive a radient floor heating system. Aside from the initial cost estimate, I looked at the amount of power required. While the overall consumption may be lower, the amount of power required to drive the pumps/compressor, several kilowatts. While the pair of 5.5 kW Xantrex inverters could handle the load, I have only 16 kWh of battery backup, which mean s on cold night, I would only get a few hours of operation of the system in the event of a grid failure. Since my goal is too reduce increase the generating capacity of my system to match the needs of my household and be as independent from the grid as possible, the ground source heat pump did not seem like a viable alternative. I opted for an outdoor wood fired boiler to heat the floor instead. Commnents?
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16 of 30
February 28, 2007
Our electric cooperative, Delta-Montrose Electric Association (DMEA), finances geothermal heat-pumps with no money down, 7.5% interest for 30 years under our Co-Z Energy Plan which also can finance high quality ductwork. This program helps overcome the first-cost barrier. For many of our members currently heating with propane forced air-furnaces, financing a GeoExchange system can put money in their pocket from day one--the cost of financing the geo system is more than offset by savings on propane. We have an installation subsidiary, InterMountain Energy, (www.intermountainenergy.com) with more than 400 geo installations in a relatively small area. We'll be highlighting these programs at upcoming conferences. For details, send me an email to public.relations@dmea.com.
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17 of 30
February 28, 2007
GAO has changed its name. It's now called the Government Accountability Office. As long as a GHP system blows something beside cold air through my house in winter, perhaps it might be something to consider. Where does the supplemental heat come from to get from 57 degrees (average ground thermal temperature) up to 72 degrees for space heating ? From a gas or electric resistance supplemental heat source ? Or perhaps solar heating collectors on the roof during the day ? What about night-time in near zero degree F. weather ? It's going to take awhile to sell me on the cost and mechanical effectiveness of a heat pump -- whether a ground or air-based system.
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18 of 30
February 28, 2007
For horizontal pipe systems, dry soil is a very poor heat conductor. For vertical pipe systems, well drilling is very expensive.

A better solution would be storing solar thermal energy under ground for winter heating and hot water and collecting and/or making snow and ice and storing it under ground for summer cooling. A tiny water pump, a blower and a one coil will heat or cool your house.
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19 of 30
February 28, 2007
I agree that GTPs are practical and applicable immediately for, as you say, most homes nationwide. I also believe that the heat source within our earth is a contributing factor to Global Warming which is being overlooked. I dont know if this is intentional for you are saying GHPs have the potential to be mainstream. I also dont know if the heat contribution to Global Warming is being overlooked deliberately. If so why? Most of us are aware of the inestimable amount of heat released from the earth both on exposed land and under the sea. We just have to look at a thermal map of the world and the oceans to see the picture of radiated heat on land and under the sea. Thanks for your very clear article.
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20 of 30
March 1, 2007
I agree that in the long run, ground-coupled heat pumps will be the best solution for reducing heating and cooling energy usage. Solar thermal has a lot of potential for heating, but cooling potential is limited. I have been trying to convince my company to push this technology but they are not seeing the demand yet.

According to ASHRAE (the technical society for HVAC engineering), "ground-source heat pumps" is used for systems that use the earth, groundwater, or surface water, while "ground-coupled heat pumps" is the subset of ground-source heat pumps which have heat exchange with the earth.

P.S. A surface water heat pump system is currently the cheapest, by far.
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21 of 30
March 1, 2007
As natural gas prices increase, and people start looking for an alternative for space and water heating... I am not sure what else people have to turn to. Of course there is solar and biomass/biogas heat.

Solar is not much help in most of the Northern Tier States during the cold and cloudy months of November and December. Biomass/gas can work for a few but not for everyone.

So the only mainstream answer I can think of: is ground sourced heat pumps (GSHPs). Lets hope they are powered by renewable kWhs rather than coal or nuke kWhs.

Hint take a look at a few GSHP stocks WFI.TO and LXU... investors see a big future in GSHPs

It is also VERY clear to me that the industry needs to agree on what a Ground Sourced Heat Pump is called.... respondents here have called it by many different names.

Also check out the Low Temperate Air Sourced Heat Pump for Hallowell Internation (google them).
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22 of 30
March 1, 2007
Thank you for a clear explanation of the benefits and potential of water based geothermal heat pumps. There are other options also. U.S. EPA recently reported on one year of monitoring of a geothermal heat pump water heating system that showed 75% savings in energy consumption. That is 400% electrical efficiency from a system that does not circulate a water/antifreeze solution through a plastic pipe and intermediate heat exchanger, but directly harvests energy in the shallow earth.
http://www.epa.gov/etv/verifications/vcenter3-18.html
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23 of 30
March 1, 2007
I live in a Minneapolis, MN suburb. I have had a geothermal heat pump for 5 years. Retrofitting a heating system in a residential neighborhood almost certainly requires vertical wells. I have five 150 foot deep wells for a closed loop system. I calculate the operating cost to be equivalent to a 95% efficient natural gas furnace with gas at $4.60 per million btu. So I would save $400 per winter on my heating bill. The environmental advantage comes from the fact that it runs off of electricity, which is getting cleaner. I buy all of my electricity from our local "WindSource" program, so I like to claim I heat my house and put nothing into the atmosphere, though I know that is not entirely accurate. If you wish more on my calculations, you can check the MN Dept. of Commerce website, edocket 04-820.11.
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24 of 30
March 2, 2007
I'm for ground source heat pumps as an alternate to fossil fuels but we need to remember that the vast majority of our power is generated from coal fired power plants. So in my opinion geothermal is not a renewable source of energy because all we're doing is trading one fossil fuel source for another, kind of like trading carbon credits. The plus side of the equation is you can see a payback in as little as one year especially if you're a contractor:)
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25 of 30
March 6, 2007
I have been involved with the HVAC business for 25 years, and have been promoting GWHP in my area of Long Island, NY for all this time. I have seen a huge increase in interest the past 2-3 years due to our very high energy costs. Being on an island we are blessed with an abundance of groundwater within a hundred feet in most areas. Although the upfront costs are somewhat higher, our local Utility company offers rebates up to $800/ton of installed equipment. These rebates offset the initial expense of the well drilling for the supply and dispersion wells, so the primary difference is just the equipment cost differences, which have come down, since copper costs have caused conventional hi-efficiency A/C and H/P units to soar over the last 3 years.
Being involved with the Solar PV industry.The net cost for operating an all electric home with geothermal and solar is usually less tha $1000/year compared to an average house of over $4000/year.
Mike Bailis
Sun Power Systems
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26 of 30
March 14, 2007
It troubling to see such incomplete and misleading reporting on ground source heat pumps.

They are complicated, expensive, glorified electric heaters, and are distracting us from sustainable green strategies, technologies, and lifestyle changes.
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27 of 30
April 25, 2007
Does anyone have feedback on an All Climate Heat Pump, offered by Hallowell? My initial research on the company looks impressive.

The initial costs for drilling the wells make a GHP system cost prohibitive for me here in New Jersey. Payback would take over 20 years! I have heard that this ACHP has efficiency nearing that of geothermal, without the drilling costs.
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28 of 30
October 10, 2007
Chris Fried, do you understand how Geo Thermal heat pumps work? They are more expensive, not much more complicated, and yes glorified (for good reason) electric heaters. But since they are only moving heat from one point to another not creating it, they can be OVER 100% efficient, the best electric based heater can only be 100% efficient. Heat pumps have the ability to be in fact over 400% efficient I've heard 900% but can't confirm it. If you don't believe me take a class on thermo dynamics, it'll help you understand. I know that the systems still use electricity, and usually more than you would want to power with solar or wind, but it is a drastically better option than spending a lot of dough on a REALLY efficient electric only heater for you home. All in all it's not the best option, but it's a good one none the less.
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29 of 30
January 31, 2008

Anyone knows the name of a company that can install Geo Thermal heat pumps in Dallas, TX? ANother question. How much at my lookg at ( estimate )? I got an old house. The house do not have air condition. I want to save money on the long run. I also want to run some of the applinaces with some solar panels that I have laready in the garage. Is a small house 1000 sq ft. The back yard is  50ft by 140ft. Is this enough land? Than you 


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30 of 30
August 19, 2008
I have a geothermal heat pump in Minnesota. They are a long term solution for the planet if action is being taken to clean up electricity generation. A homeowner that installed a system like mine today would emit more CO2 and pollutants than a 95% efficient natural gas furnace. However, Minnesota has a law requiring us to cut our CO2 emissions 80% by 2050, so as we 'de-carbonize' our electricity supply, we could be 'de-carbonizing' our residential heating system. I buy all of my electricity from our local utilities "WindSource" program, which means that the net energy to produce the electricity to run my heat pump produced no emissions. If you do install one, I recommend following the Canadian Office of Energy Efficiency guidelines and installing a system that will handle 60%-70% of the maximum load with a supplement(usually electric resistance) to handle the rest. It significantly lowers the installation costs on vertical closed loop systems, while only slightly raising heating costs.
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