Years ago, when I first heard the name “Geothermal Heat Pump” (or GHP), I was intrigued by the thought of heating and cooling my home without burning anything. Since a GHP could transfer heat energy from the ground into our new home in the winter and then transfer it from the home back to the earth in the summer, we would be “borrowing” heat.
And so I started to do my homework to learn more. I wished at the time that a book had been available to tell me everything I needed to know about heat pumps. Instead, I had to do it the hard way. I used the Internet for research and built a network of experts in heat-pump manufacturing, installing, training and even in the academic world. It took me three years to become conversant with the subject.
HOW HEAT PUMPS WORK
The first thing that I learned was why it was called a “heat pump.” Heat energy flows spontaneously from the warmer substance to a cooler substance—never the other way. That is akin to water flowing downhill. But in a heat pump, we are doing the opposite: using a bit of electrical power to move heat energy uphill from a cooler location such as the earth to our warmer home. So, using the term “heat pump” is very apt.
The second thing I learned was that when you compare all of the methods of home heating—geothermal heat pump, oil, natural gas, electricity, coal, propane or wood—the GHP was far superior in terms of renewable energy, pollution, and, most importantly, the cost to operate it.
That lower cost is primarily due to the extraordinary efficiency of a heat pump. And that efficiency is due to the fact that for every unit of input electricity, we are getting three units of free energy from the ground. That means four units of output energy for one unit of input. Imagine getting an efficiency of 400 percent when my old oil burner had, at best, 86 percent efficiency!
It became clear that this is not an example of exotic, new or strange technology. Heat pumps have been around since the mid-1940s. They use well-known refrigerator technology. There are millions of installations worldwide working right now. And this is a renewable resource!
I made a decision: my new home was going to have geothermal heating and cooling. I expected these benefits:
● No burning, therefore, no pollution, therefore, no fossil fuel delivery. Therefore, no on site storage such as fuel tanks or bottles.
● Savings of at least $2,500 every year. I have an estimate that my home would have required 800 gallons of #2 fuel oil per season. At $3.80/gallon, my annual savings is closer to $3,000 now.
● Full air conditioning or heat at the click of a switch. There are times during spring and fall when we need both in the same day and this can be automated. A simple reversing valve redirects the flow of heat energy.
● A very quiet operation. Our last home had a basement oil burner under our bedroom. We had an enormous and noisy rush of air at startup and a continuing roar. Heat pumps are disconcertingly quiet.
● Less maintenance. No annual cleanup, no nozzles with half burned oil residue, no nozzles at all, of course. You do need to clean the air filter just as you would with any air delivery system or the heat pump will shut down during a snowstorm and annoy the whole family.
● No chimney needed. All homes have chimneys, don’t they? Well, no, I was not going to add one for its architectural value. But later, we began to think of a backup in case of a power failure. So we added a wood-burning stove with its chimney. On a snowy, winter night we love to watch the glowing embers and dancing flames.
● Very comfortable living conditions in all seasons.
● Subsidies. I received only a $500 rebate from the state of New York. Federal subsidies are now far better: a 30% tax credit for the entire installation. Some states and some utilities also provide incentives. Check out your state at www.dsireusa.org.
● Home value. The EPA estimates that home values increase by $20 for every dollar that is saved in annual costs. So if you save $2,000/year with a geothermal heat pump, the value would go up by $40,000. At the very least, this technology makes your home more saleable.
And all of this is exactly what I received! It was one of the smartest decisions I ever made. And the higher the price of oil or gas, the smarter I feel.
In the beginning, as I started the building process, I discovered misinformation, lack of knowledge, even uneasiness about this “strange” system. Knowledge about heat pumps is slowly increasing but in my experience, obstacles had to be overcome before I could proceed. For example, I had hoped that homeowner’s insurance companies would provide a discount for heat pumps because there would be a lower probability of fire or carbon monoxide poisoning.
So I asked my agent to contact a number of companies. The answer: “Well, none of them really knew what a heat pump was but heating systems never rate a discount.” Then my architect told me to forget a heat pump, “Your budget will not allow it.” And my builder, really one of the finest, was very reluctant to install a system that he was not familiar with. So, I got bids on a heat pump installation and signed a separate GHP contract.
PERSISTENCE PAYS OFF
But the biggest horror story came from my bank. After months of almost foot-high paperwork to obtain a construction loan and after dozens of meetings, we were advised that our application had been approved, but subject to a single change. The geothermal heat pump was not permitted! Why? “It does not meet Fannie Mae guidelines.” How? “Well, it is just too different from other homes.” This made me so angry I could spit.
I sat down and wrote a letter and sent it to every key person in the bank. I explained what a heat pump is, how it increased the value of my home, how the bank was contrary to U.S. official policy in reducing pollution and our dependency on foreign oil. Two weeks later, they agreed! All of this took persistence and education.
GHP FOR YOUR HOME
If you are interested in saving money with a GHP, you should ask the question: “Well, the operating cost may be the lowest of any method of heating my home, but what about the initial installation cost? Is that not much higher than any other approach?”
The answer is, “Yes, but not necessarily.” There are installations, like mine, that use ponds or wells as a heat source and may not be more expensive. But in most cases you will have sticker shock when you see the first contractor’s bid. Do not panic, all is not lost. First, you are going to install some type of heating in your home anyway. So the question should be, “What is the added cost, if any, of a GHP over any other system?”
The biggest difference is in the cost of the ground loop where heat energy is obtained. That in turn depends on the type: a horizontal trench, one or more vertical boreholes or the use of a pond or even a well.
The numbers given here will be different than yours because every home and every site and locale are different. Let us assume that a fossil-fuel furnace plus air conditioning (A/C) is $20,000, while the total GHP cost is $40,000.
If you then factor in the 30% federal tax credit for the entire GHP system, which amounts to $12,000 in this hypothetical case, the installation cost is reduced to $28,000. And you will be saving thousands of dollars each and every year in not needing to buy fuel. That $8000 difference could be recovered in a few years. Overall, you can’t lose. The payback time is short, if not immediate. In addition, many states provide additional subsidies.
COOLING FOR FREE
At the start, I mentioned cooling as an important side benefit. Consider also: this comes free! It is already built in. While the geothermal heat pump operating in the cooling mode uses essentially the same theory of operation as a residential A/C system, there are two major differences.
First, a standard A/C system requires a large outdoor heat exchanger in your backyard to dump heat energy into an already hot and humid atmosphere. This works, but it is very inefficient in that it takes a lot of electrical energy. The GHP needs no outdoor equipment. Secondly, a standard HVAC connects two separate systems (A/C and furnace or boiler) at the ductwork. The GHP is a single system that reduces operating costs and increases efficiency.
CHOOSE A CONTRACTOR
Before you can get any idea of what a GHP system will cost for your home, the system must be precisely defined. This is no do-it-yourself operation unless you have experience in the field.
I strongly recommend that you hire an experienced, accredited installer with dozens, maybe a hundred successful installations. He should have a GHP installed in his own home, should use a computer software program that requires plugging in details about your home: square footage, number of floors, number of zones, windows, insulation, the house orientation, the latitude, type of heat delivery approach you want, (hot air, hot water, radiant heat), etc.
From this he can calculate the size of the GHP needed. Getting this right for your home is very critical—too small and it will not heat the home properly, too large and it will cause the system to “short cycle” or turn on and off too quickly in the cooling mode and cause unnecessary wear.
Once the size is determined, he can start to specify the ground loop to support that heat load. Here is where you must be involved but contractor knowledge of the local topography will be helpful. Is there ledge, what is the local ground temperature, how much land is available for trenching, what type of soil, is there a pond close by, etc.? The type and cost of the ground loop is dependent on the answers.
Get a bid in writing and a copy of the software printout. Get more than one bid, if possible. To find local contractors, go to the IGSHPA (International Ground Source Heat Pump Association) website, igshpa.okstate.edu/directory and select “accredited installers” and finally select your state.
And lastly, in making your decision, I urge you to think long-term benefits and costs, not just the startup costs.
Cut through the next storm-induced blackout by prepping with the right gear
by Denis Prisbrey / Feb 28, 2013