We’re looking to put up a greenhouse next year but I’d like to have a better idea of the costs involved in terms of heating. Anyone care to share some figures of how much they pay to heat theirs in the Spring?
Please specify fuel source (oil, gas, etc.), volume heated, and greenhouse construction (double poly, etc.). Thanks!
We just converted a permanent hoop house into a heated greenhouse this past year so I only have 1 year’s worth of data but here are some of our costs…
24’x48’ hoophouse (originally built as single layer house which cost around $3000; converting to double poly with inflator fan cost about $500)
Modene propane unit heater $1000 or so.
Installation and electrical inspection of furnace (we hung the furnace but had to have HVAC/electrician to do final hook up) $800
Propane tank rental $90/yr
Cost to install tank and connect to tank $300
Cost to fill tank $850 (propane costs are fairly low this year, can’t remember the per litre price).
I dug all the trenching for electricity and propane lines to save $ and my husband did the electrical hookup.
We fired the furnace up the last week in February and heated as needed until mid-May. We also put an old woodstove in the greenhouse as secondary heat or as power failure backup. It provided minimal heat - old and not very efficient. Plan is to add a rocket mass heater this summer and only use propane furnace as nighttime backup. We live in 45 min north of Guelph in zone 4b (but more like 5a last few years).
We went through approximately 2 full tanks of propane for those not-quite 3 months. And we only had the furnace set to 8 degrees, so lower than many people heat. And it was a mild winter for us. On a sunny day, it would get 25+ degrees but of course on cloudy days and at night the furnace ran all the time.
To help hold the heat we sealed our big double doors on either end with poly on the inside and installed a small ‘man-door’ for us to go in and out.
One thing we didn’t get installed and should have was the gable automatic vents. Sometimes it was pretty humid/hot in there and it was hard to ventilate properly. We didn’t have any mold issues but did have aphids.
It was/is a fairly costly investment but after 3 years of growing all our starts in a cramped and drafty sunroom in our house, it was well worth the cost. Everything was so much more efficient in a larger space that was properly organized and the transplants were healthier and happier.
Thanks for sharing! I’ll consider all this when pricing it out this fall.
We are in the final stages of getting our greenhouse (20’x48’) outfitted with a propane furnace. This is great info, as we’re been trying to figure out how much it’s going to cost to heat from late Feb-May.
Just curious…is your propane cost for a single or double layer of plastic? What size is your propane tank?
Our greenhouse is double poly and I believe the tank is a 500 gallon (1500L) tank. Hope that helps!