Alternative Heating Systems: Geothermal vs. Natural Gas
LESLIE: Curtis in Texas is looking into some alternative heating methods. What can we do for you?
CURTIS: Hi. I was wondering y’all’s opinion on – we’re building a house up here at Georgetown. I’ve been looking into a geothermal system.
CURTIS: And I was wondering what your opinion would be on a geothermal system for this part of Texas and what type of sizing. Would it be the same as a regular AC unit as far as tonnage? Or would it require more or less?
TOM: Well, a ton of air conditioning is the same ton of air conditioning regardless of whether it’s created using a geothermal heat pump or a standard air conditioning compressor. So a ton is a ton; it’s 12,000 BTUs of cooling capacity. So the size is going to be dictated by the cooling needs of your particular structure.
Now, whether you go with geothermal for your heat is really the question. Is gas available in this particular area?
CURTIS: No, it’d be propane.
TOM: Well, I’ll tell you what. If I had to decide between propane and geothermal, I probably would go geothermal. But if it was between geothermal and natural gas, I’d stick with natural gas.
CURTIS: Is that for cooling as well?
TOM: Well, yeah. Once you install it, it’s going to be – basically, what you’re going to have here is a geothermal heat pump for heating and for cooling. But most of them have an electric resistance backup system so that if the heat pump, for any reason, can’t keep up – if you get a real cold spell – the electric resistance heat comes on and kicks in. But mind you, when that happens, it costs two to three times more than when – to heat than when the geothermal is running by itself.
One of the things that you’re going to want to make sure that you get, Curtis, is a clock setback thermostat that is specifically designed for a heat pump. Because it inches – very, very slowly – the heat up and down. A regular thermostat will move it up and down just in an instant; it can drop 10 degrees or go up 10 degrees in an instant. And if you do that with a geothermal what’s going to happen is the electric heat backup will come on and work very hard to bring the heat up very quickly, but that’s expensive. With a clock setback thermostat that’s designed for a heat pump, it does it very slowly so as to not trigger the electric resistance unless you really need it.
CURTIS: Very good. OK, you think that, though, that the geothermal system – that the cooling side of it would work fine with the temperature gradients that we have around here.
CURTIS: OK. Well, very good.
TOM: Because it’s in the soil – it’s in the soil so the temperature is stable.
TOM: Curtis, thanks so much for calling us at 888-MONEY-PIT.