cost of heating a green house in the winter

[ericst11]

I was thinking of puting up a 10ft long by 12ft wide by 10ft high green house and was woundering if some one could maybe tell me the cost of heating a green house in the winter , I live in nebraska .I was also woundering if any one has worked with some sort of solar heating to heat it .

[RonCo]

Your greenhouse would have about 500 square feet of surface area exposed to the outside cold. If you were to keep the inside at 70 f on a zero degree night it would take about 40000 btu per hour to maintain the temperature. Natural gas has roughly 1000 btu per cubic foot plus there is an efficiency of the furnace to consider, maybe 80%. So it would require about 40000/.8= 50000 btu per hour input to the heater, or about 50 cubic feet of natural gas. Natural gas is sold by 100 cuft. In Ohio current gas costs are about $1.37/ 100 cuft so it would cost about $.70 an hour during the night to keep the temp at 70 f.

This is based on using a single layer of 1/8" glass as the glazing. If you used something like double or triple wall polycarbonate glazing the heating cost really goes down. Using something like 16mm 5 wall polycarbonate would reduce the gas consumption to about 15000 btu per hour. A big savings over 50000 btu/hr.

Here's a link to a calculator to figure how much heat is required for different glazing materials. This will give you how many btu's you need per hour. If you really want some scary numbers try +70 f on a -20 f night.

Try some different glazing materials and inside temps to see what it would cost. That 5 wall polycarbonate starts to look pretty cheap after a while.

Ron

ACF Greenhouse Heaters & Heater Size + Cost to Heat Calculators

[John D.]

That is a great link. Saves me the time and effort to set up a spreadsheet. Thanks

John

[ericst11]

thank you very much and thank for the link.

[NAgreenhouse]

We have a 10mm twin walled 8' x 14' greenhouse and live in Western Colorado. Get's real cold at night. Never figured the costs, but we keep it at 75 degrees at night and use a 10,000 BTU natural gas heater (vented) and it keeps it warm.