How to heat your greenhouse cheap

[timv]

Well, not too cheap, since you've got to put several hundred dollars into it, but as far as long term cheap heat, here's what I came up with. The trial and error cost me more stress than you, dear reader, need to go through. But this worked all throughout this last year, and it cost about one dollar per day in extra gas bills during the cold part of the year, from October to March.

You take a gas water heater like the one you have in your house and put it as close as you can to your greenhouse. If it's farther than a few yards, no big deal, but you'll have to insulate the lines. Then run a closed loop from the water heater and back again. The loop is made of your choice of plastic tubing. The loop goes along the shelves, by the base of the plants.

Here is the pipe by some carnivorous plants and orchids

[timv]

Then, somewhere in the loop (it doesn't really matter where) you put in a pump. The pump circulates the warm water from the tank through the pipe/s and back into the hot water tank. You can see it's now disconnected for the summer:



Then, you hook up the pump to a thermostat, so the pump is only working when the temps drop to the danger level:



Simple, cheap and elegant. Not that getting gas and electricity to your greenhouse is always the easiest thing on earth, but I trust you all get the idea.

[chelmuth]

This is a very good idea, Tim. If I ever get a greenhouse that is too cold I'll try this.