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heating question - what is a 'therm' vs BTU's?
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Posted by hairmetal4ever Z7 MD (My Page) on Sun, Jan 31, 10 at 12:30
| I am looking at my natural gas bill to try and get a ballpark of heating costs...but instead of pricing by BTU/hr, it uses "therms."
So if I used 105 therms in a month, how does that compare to BTU's? Supplier is BGE (Baltimore Gas and Electric) if that makes a difference. |
Follow-Up Postings:
RE: heating question - what is a 'therm' vs BTU's?
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| A therm is 100,000 BTUs. Dan |
RE: heating question - what is a 'therm' vs BTU's?
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| So in a month, I used (in this example from my October useage) 10,500,000 BTUs in a month, or, about 14,112/hr. |
RE: heating question - what is a 'therm' vs BTU's?
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| Is this just for the GH or combined dwelling and GH usage? Dan |
RE: heating question - what is a 'therm' vs BTU's?
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| Just dwelling at this point - no GH yet. Trying to price it out and comparing needed/expected BTU usage (from calculators on littlegreenhouse.com) to current. |
RE: heating question - what is a 'therm' vs BTU's?
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| My natural gas is calculated by volume at the meter. There are many variables in estimating the cost of heating g'houses and comparing them with household use really won't get you there for many reasons. How expensive your structures' useage ends up will depend not only on their size, but how tight they are, what kind of glazing you use, how efficient your heaters are, what seasons you heat them, what you are growing in them and their heat demands, your weather that particular season and how many sunny days you get to advantage solar gain. G'house engineers will not only ask you about your structure's size, and shape for air volume, but also what your anticipated heat rise is. I grow Easter lilies. They're an expensive crop for me because they're started in December, and their success is very dependent on regulating temps to their needs. If they're behind they need pushed, for example. One year we had three days of minus 23 degrees and they needed to be run a hair above seventy. My poor heaters cranked continuously to struggle to keep it there. You could watch the gas dials spinning. Each degree you raise it above outside ambient is more expensive than the degree before that. Cost does not increase evenly. I can have a house cost me three hundred one month, and nearly a thousand the same month the next year. |
RE: heating question - what is a 'therm' vs BTU's?
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| Here's my plan. Heating season will be sporadic in October and April, but pretty consistent from Nov - March. We get ~40% sunshine in Dec and Jan, probably more like 50% the rest of the heating season - on sunny days it's likely I won't need any heat and will actually have to ventilate. Days average around 42 in January, nights about 22, can get to zero on extreme cases. Mostly, I'll grow cool-season crops like lettuce, but keep it warm enough for citrus and bananas to do relatively well, since I'll probably heat the soil in their pots to around 68 degrees - this way I can get away with cooler air temps. I plan to heat to around 63 day, mid 40s at night most likely, but if the bananas and citrus aren't happy I might have to kick that up some. However in my past experience, if the roots are kept warm as I said above, they'll do OK in cooler air temps. I'll probably use Empire DVE heaters, and a Cross Country 12 X 20 GH with twinwall polycarb...might go fivewall. |
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