As most on here know, I am pretty stupid. I cannot understand how 50 degree water can warm a home past 50 degrees. Without help. My owb is 190 and warms the house easily to 75 and water to 130+. If this is true, shouldn't the reciprical be true that my OWB can cool my house from 95 to 70 in summer?
Physics were not my strong point in school. And as I said I am pretty dumb. I also have a friend that is saving money with geo. She needed a 200 amp service installed to run a 90 amp pump and still has not paid for a new transformer on the pole that will allow for a 100 amp heating booster. I still believe electric is more $$$ and less efficient than propane, which she took out.
I still don't understand. Back to sentence #1.
Don't feel bad. It took me months of study to figure out how it works. I'm building a new home this summer and seriously considered geothermal. In the end, it's too expensive and I'm on 45 acres of trees that I can use to heat with. So I'm getting an OWB with a propane furnace for backup.
It's actually a ground-source heat pump, because it's pumping heat molecules from the dirt into your compressor which compresses the heat molecules which causes their temperature to increase. It then blows out the air through your air ducts (I've been told air ducts are the most efficient with ground-source heat pumps). There are also air-source heat pumps but they falter when it gets below 30 degrees F. Anyway, the way it works is to think of it as electrical heat. You use electricity to run your compressor. The liquid flows through the ground. Liquid picks up heat from the dirt. Liquid is much more efficient for transferring heat than the air is. The compressor grabs the heat out of the liquid as it passes through, compresses it and raises its temperature, then blows it out. The now colder liquid goes back into the coils buried in the earth to collect more heat. The wetter the soil the coils are buried in, the better it works. If you use a pond or a well loop it's even better because liquid passes heat molecules faster and more efficiently than dirt does.
The problem is that the liquid is coming into the house at about 33 degrees F in the dead of winter, because as you pull heat out of the dirt it takes awhile for more heat to move into contact with the coils from the other dirt that is still at 40-50 degrees F. So as your outside air temp drops significantly, the ground-source heat pump needs help to create enough heat. That's where the integrated electric heater kicks in (or propane or some other type) as a supplement.
In the end, you're paying money to the electric company instead of the gas man. It's much more efficient than a propane furnace though so it is cheaper than propane. However, it's hard to gauge paypack on the investment until you have it installed and see how much you pay in electric to run it versus how much you paid in propane (and the electric to blow the hot air around the house via the propane furnace). The ground-source heat pumps run the most efficiently when they're running 24/7 and are variable stage rather than just 2 stages.
Where ground-source heat pumps shine is in cooling the house. It runs in reverse, pulling heat molecules out of the home and sending them out into the dirt through the coils that are buried. It basically turns your house into a giant refrigerator that way and is more efficient than an A/C unit.
Cost is just so expensive though, and without a guarantee of the"payback" I'd rather heat with wood. Especially since the IRS in November released an opinion that the 30% tax credit doesn't include your ducting system like it used to. That meant it would have been an additional $3K or so out of pocket if I remember my estimate correctly.
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Topic: Why didn't I just get geothermal (Read 16126 times)