Geothermal heat pump systems (also known as GeoExchange, ground-source, water-source heat pumps, earth-coupled heat pump, heat pump ground-source, or ground-coupled heat pump) are without question one of the most exciting products in the world’s quest for alternative and renewable energy sources. A geothermal unit will reduce your homes carbon footprint, and reliably warm and cool your home for many years. Best of all, a geothermal heat pump system can save you 70% or more per year on home heating and cooling bills!
A geothermal heat pump system can save you 70% or more per year on home heating and cooling bills!
With home heating oil reaching $5.00 a gallon, it’s not uncommon for a family in the northern parts of the country to spend $4,000 or more heating their homes during the cold winter season. In the warmer southern areas, electricity bills of $300-$400 a month are not unusual as families battle the heat with inefficient air conditioning systems.
As the name suggests, geothermal systems heat or cool your home using the relatively constant 55-60 deg temperatures found only a few feet below the ground. Even in Northern Maine, where the temperatures routinely dip below zero in the winter time, you can find temperatures of 55 deg (F) just below the surface, more than adequate for the installation of a geothermal unit.
How Do Geothermal Heat Systems Heat?
Geothermal heat pumps create heat in the winter by circulating radiant heat trapped in the earth (via a closed water loop) into you home. The heat is extracted from the water via a special heat exchanger (similar in size to a central air unit) where the temperature is “compressed” another 10-15 degs warmer and distributed throughout the house. The heat can be distributed utilizing your home’s existing radiant, baseboard, or forced air systems with only minor modifications. There are absolutely no fossil fuels to burn, only a marginal amount of electricity to run the transfer pumps and compressors.
How Do Geothermal Heat Systems Cool?
During periods of warmer weather, the system operates in reverse. Cold water is drawn up from the ground into the heat exchanger where it is then distributed throughout the home cooling it off. The water then carries the heat away from the home back into the ground where it is cooled and the process repeats.
How Much Do Geothermal Heating Systems Cost?
As you may expect, residential geothermal heating systems are more expensive than traditional heating and cooling systems (complete systems run about $2500 to $3500 per 500 square ft of living space). However, with the rising price of oil, gas, and electricity, a properly installed geothermal heat pump system can literally pay for itself in only few years. Furthermore, you will begin reaping environmental benefits as soon as the system is brought online.
Buyer’s Assistance Programs
Purchasing a $15K to $20K system is a huge financial investment. Many homeowners simply can’t afford such a large investment to convert to a more energy efficient geothermal system. The good news is that many states offer financial incentives to individuals and families looking to make their homes more energy efficient. These incentives range from low interest loans to comprehensive grants that cover all costs. To find if your state offers these programs, check out the Database of State Incentives for Renewables and Efficiency (DSIRE), click your state and the site will display your state’s specific incentive programs along with how to apply.
Finding a Contractor
The key to hiring a good contractor (especially in this relatively new field)is asking for recommendations. Ask for a client list from a prospective contractor and don’t hesitate to call them. My buddy’s wife actually visited the homes of her contractor’s previous clients before deciding on his geothermal system.
Related Articles:
An Explanation of how Geothermal Heat Pump Systems Work
Insulated Concrete Forms (ICF): Green Building Technology
Do It Yourself (DIY) Geothermal Cooling System
Should You Pre-Buy Your Home Heating Oil This Year?
Do It Yourself Home Energy Audits
36 Ways to Reduce Your Home’s Energy Use
{ 26 comments… read them below or add one }
Do you have one of these things? Is it possible to do our own digging and install something like this ourselves, you think?
I have heard of the concept of power plants that bury huge tanks a couple of miles below the service and use the steam from those tanks to run a reactor. Is that called Geo-Thermal?
Anyway, cool idea. I just wish there were ways to cut costs by doing some stuff myself.
Great post, bookmarked! I hadn’t realized that the residential systems were that cheap, would have guessed higher.
No I do not have one of these systems (YET).
Unfortunately my wife and I built our house a couple of years ago knew very little about these systems. The technology is so amazing that we may (eventually) upgrade our system anyway.
I wouldn’t recommend doing this yourself. I would seek out an experienced contractor in your area.
Wow… those savings are HUGE! It’s a great idea too!
I wouldn’t be able to afford something like that for awhile, but it’s definitely something to consider when I settle down in my own home.
Great post.
Wow… those savings are HUGE! It’s a great idea too!
I wouldn’t be able to afford something like that for awhile, but it’s definitely something to consider when I settle down in my own home.
Great post.
Great article. I have been researching geothermal heat for a few years, and have realized that the biggest savings is in the cooling.
Southern states are more likely to save money then northern states. I live in MN next to Canada, so I don’t run my air conditioner very much so the only benefit would be in heating my home. My calculations put the return on investment at about 8-10 years – that is if I stay in my house that long. Therefore, geothermal energy is not a good investment for me at the current energy prices. Wood burning seems to be the cheepest energy source for me to reduce my heating costs.
There is a big initiative back in Maine for an increase in wood and pellet stove use.
With over 80% of Maine homes burning oil, and oil at $5.00 a gallon, you would see tremendous savings in your energy bill and possibly have your system “paid for” in less than 10 years!
Besides the immediate cost savings, I wonder how much you’d recapture on various energy-saving projects upon the sale of the house?
The value of this system is huge as it saves you on energy costs and seems like it’d need little maintenance yet would last for a while. As some of the commentators have pointed out it might take 8-10 years for one of these system to pay itself off but it seems these systems would last way beyond that meaning eventually it’d be a great investment, no matter the energy costs.
We installed geothermal in our northern Minnesota home this March. We retrofitted it to a forced air system and were quite happy to cut the line to the fuel oil tank! We were burning about 500gallons of oil per year to heat our 1400sf home. We did an energy audit, and estimating the price of oil at the time at $3.25 per gallon our payoff would be 5-7 years. Well…we all know that oil has gone up at least a $1 since then, so payoff will be sooner. We actually use the air more than we thought we would, it’s running a couple times most days and is costing us $5 to $10 a month. We installed the desuperheater and are getting hot water heat during the warm months for free. So far our estimated cost to run are very accurate and we will expect to spend less than $500 for annual heating and cooling. The system cost us 16k…I don’t regret the decision one bit. You do need a large lot to do it if you choose to do a horizontal system. It is DEFINITLY not a do it yourself project.
I am looking into geothermal and have now received quotes from several companies for several different types of systems. If you are retrofitting existing hot water baseboard please be prepared for a very high price quote, much more than $15-20,000. The cost to retrofit your home to forced air and/or radiant is very expensive and if you don’t want to worry about feeding off your existing well and choose to go with a closed loop system be prepared to pay another premium. We are trying to decide if it is worth it. How long will it take the current housing market to catch up with the $40,000 we may drop on home heating? I’m really not seeing anyone ask that particular question.
We paid 16K total for a forced air retrofitted – horizontal closed loop system. Our home is modest size at 1400 square feet. I would suggest getting a few bids, $40k sounds really high unless you’ve got a huge house or need to dig several wells. Doing a horizontal dig is much less expensive but you need the space. At our price our payback is estimated at 6 years…not a bad deal when you consider that estimate is based on fuel oil prices of 3.25 per gallon.
From what I understand Geothermal does not work well at all with hot water baseboard heat because it will not heat the water hot enough. As for being more expensive to retrofit to forced air..I don’t agree, we paid $400 to have some ductwork done to make the system work.
I just want to rig up a little Geothermal Space heater that I can run a few hours a day.
Here’s a URL to my posts at DIY.
http://forum.doityourself.com/showthread.php?t=361014
If I get it installed and the basement floor can’t recover within 12 hours, I might try adding an closed loop down in the back yard. But below 3-4 feet, I’m in the water table.. Muddy!
Mild winter days:
Another idea would be to vent in outside air to the basement when it was warmer than the air inside the basement. Quicker recovery.
Sunny Days:
Attic fan driving hot air down to the basement via a 15′ duct.
(If the roof isn’t covered with snow).
Man it’s hard to keep warm these days!
I live in Indiana and bought a 2800sqft house last year – with geothermal. System is about 12 years old. It has save me a fortune…… my highest bill the whole year was $143. This includes the hot water, electric and heating. I average year round about 85 a month year round for everything. It is only 2 of us…. however, you wont ever walk into a cold house to save money…. and my daughter isnt that frugul
…
“blessed be” the geothermal system…
Hi,
I work for the national industry association in Canada, the Canadian GeoExchange Coalition. These systems do indeed reach this level of savings – we see a rough average of 50% savings in energy for residential installations (cost savings will differ according to your local utility prices).
However, one thing that’s important to emphasize from our point of view: there is no quality assurance program in the United States. You the homeowner are at the mercy of the contractor until a US quality program is established. We do not accept the three-day training in our quality program in Canada.
The contractor you talk to may be really well qualified or may not be qualified at all – a three day classroom course is all that’s required by most manufacturers / distributors to sell their heat pump, though some like WaterFurnace, EarthLinked and Earth Source Energy, have built their own in-house training in to a more comprehensive approach.
Please see: http://www.geo-exchange.ca/en/canadian_geoexchange_coalition_warns_of_contractor_nw124.php
for a relevant consumer advisory.
Please also note that there are a few contractors who are applying to be CGC Accredited, ie qualified under the only _quality_ program in North America. This requires basic installer training, additional specialized training, insurance and relevant work licenses, as well as actual work experience and written affidavits to follow the industry code of conduct. You may find a growing list of names on our site for US accreditations in future, but for now the US market is wide open to the fly-by-night contractor. Please be careful.
TedK,
Thank you very much for that information! That is very good to know and I hope my readers take into consideration the experience level and qualifications of any geothermal heating system installers before signing any contracts!
Do it yourself, dig a hole, concrete a box in the ground several feet below the frost line, make it long, pipeing coming out of both sides on opposite sides of the box going to opposite sides of the house, drop in several good sized river rocks, concrete seal the top, cap it, bury it, put a quiet industrial fan on one side, run your duct work off the other side, and bammmm nice, cool, FREE, except for what it costs to run the fan, cave like temperatures all year around, whick is nice cause I like it cold. And you did this yourself for around 2 or 3 thousand, and a hole about 10 to 15 ft long by 5 to 6 or 7 ft wide. Sod it back nothing more than a backhoe needed.
i’m in s.c.witha 2 year old icf home 2700sf.have a 2ton fhp closed loop system consisting of a 150 foot trench 6 feet deep with 1000 feet of 3/4 pex in 3 foot loops like a laid down slinky backfilled first 2 feet with riversand to make sure i have moisture touching pex this is my design and it works great .i own a backhoe so the trench and backfill cost nothing but i only paid 5500.00 for the heatpump.ductwork,and the retired hvac techs labor.use your heads instead of your bank accounts and we all save money and get greener lives thanks and god bless
i see i neede to leave my email address it’s mstockton@prtcnet.com be glad to help some of you save money mike stockton
Hey Mike! That sounds awesome! If you have pictures of your project I would love to use them as the basis of a new article! I’ll send you an email!
That is a fantastic article. Now with the tax credits, geothermal has become very affordable.
You all seriously need to chekc out geothermal energy. It is the way forward. I swear by it, and I can’t say enough about it.
Ryan, do you have a geothermal energy unit in your home? I would be interested in hearing about it!
I have no engineering or other related education training or aptitude, so I am probably missing a key here. I would be most grateful if you can tear me apart, since my feeble mind cannot see why geothermal cannot be a simple diy project. Thanks so much for your critisisms folks
It seems to me that we might be talking apples and oranges, not in the use of geothermal but in the efficiency of the product. My thinking is that we may be able to do a diy job to get benefit from this source of energy but that it would not be the great return that a pro job would give. Now this trade off is to be considered in light of the great differences in cost the professionally installed vs the diy project would involve. Still with me here?
The exchange of heat
My understanding is that the basics of this is that:
1. the temperature of the air in the house is at a different temp than the liquid from the ground
2. the principle is that when these two meet the basic physics is that the two “banks” try to equalize out, or go to the same temperature.
Am I right there?
The two banks
My vision is a loop or tubing running underground and a separate loop of tubing running in the house so that, before the two loops meet, they are at different temperatures. This to me is just restating the foundation of the whole system. Do I have this right?
The interchange of the two banks
Now, if we bring the two loop systems together, they will by their own magical powers try to modify each other, so that we wind up with an end product that is not as warm as the warmer one and not as cold as the colder one. Right?
Can this interchange be as simple as weaving the house loop over and around the loop from the ground, so that the two loops (here it would be copper tubing since it is the most conductive, right?) come into as much contact as possible. If this interaction is in a closed and insulated unit then it should be the most efficient. Right?
My thought on this unit would be to build a bench at the back of my garage and insulate it then run a length of insulated, perhaps 6” diameter pipe through it. The copper tubing would run through that pipe.
I just have no idea how much intersection is needed here. Perhaps it would have to be the entire rear wall of the garage, insulated on both sides to improve efficiency?
The in ground loop
From what I have read, this is a major key to the effectiveness of the whole system. We need to have the external loop in a proper location so as to be in an area with constant temp and an area where the transfer of temperature from the home will not impact the temperature of the surrounding area so as to negate the benefit of routing the loop through the ground. This later concern is one of the reasons why we need to have long sections under the ground, with the other reason being the volume of the liquid pumped through the system depends on the cubic area in the home we seek to moderate. Right?
Running Water
If we can tie into subterranean water then we have the benefit of constant heat normalization by the moving water taking with it the temperature difference that was brought in by the loop after it passed through the house. This assumes that the water into which our unit is placed is itself at a constant temperature, as would the ground be beyond a certain depth. Right?
Most of us in suburbia do not have streams or ponds in our yards into which we can place the loop. But here comes my insane idea.
We in suburbia do have a water line coming into the home, and I also have a drainage system running around the yard, a number of feet down, to drain the water from what would be the water table mark. Suppose we take advantage of this but wrapping the ground loop around, or perhaps just under these piping systems? This is what I am the most excited about. The water would serve to eliminate the constant flow of different temperature provided with the “used” liquid as it flows through the outer loop.
Well, there you have my craziness. I do have some other questions.
First, assume I use one of the small pond pumps to move the liquid through the system, is there a way to figure out the size of the pump (gallons per minute) that I need?
Second, how do I attach the pump? I know that there is one end that has a nipple onto which tubing is placed, but the intake part is usually a large area.
Third, for economy, I would use black plastic pipe under grounds as much as possible. I would try this in my 20 x 20 or so garage first, so I think one 400 foot line might be enough. I keep reading of having to fuse the connections. Is there a way to connect lengths of this plastic piping to one another, and also to copper tubing, that would not require an expert?
Finally, can the inground loop simply deposit into a water tank, such as a 30 gallon bucket, into which the in house loop is run, and then pump out the other side, or do I have to keep it all in the tubing?
Many thanks,
Kevin
Buffalo NY
If you would like to learn more about geothermal systems. I recommend this website and his guy – Tim Uzar. Read his bio and look through his site. It is chocked full of info.
Here is another explanation..