With the price of fuel sky rocketting, your idea of a wood burning furnace sounds great. What type are you using? I am considering doing this myself. Best of luck!

I know of a few people using them and the outside furnaces are not limited to wood or coal. I priced one at a Ag trade show that was burning soybean hulls and could burn corn,wheat, barley or most other grains. The heaters can usually be used to heat 2 or more greenhouses. The catch for me was the price of the exchanger units which mount inside the GH and the circulation pumps and insulated lines needed to carry the exchange fluid to and from the GH. You can easily double the cost of your GH with one of these units.

I heat my smallest GH with wood but it is an internal unit. Its no small task to start a fire every night and then tend to it every 5 hours but then it cost under $20 for the stove and I usually only need it 6 weeks in the spring.

Wood heat is usually considered cheap but if you need to buy the stove, a heat exchanger, pump, run electric line, pour a concrete base and pay a hefty installation fee it may not be worth it. If you don't have free wood or need to purchase a chainsaw, splitter, solar dryer, truck and wood storage shed then you better rethink the idea.

The outside wood furnace is a Woodmaster.It will heat 5000sq.ft. This will heat our house, the Saw sharpening shop and the greenhouse. It cost us $7,400 installed.We already have a wood splitter,and we buy our wood by the 10 pulp cord load. What will be so nice about this heating system NO MORE HAULING WOOD THROUGH THE HOUSE! We only need to fill this stove every 8 to 12 hrs. Our furnace in the house is forced air, at$2.08 cents a gallon for propane, it figures that we will have this outside stove paid for in about 5 years on the savings. The greenhouse will be heated by baseboard hot water heat., this only added 400 dollars on to the price of the stove. I will let yu all know next spring how it worked. I`m excited to be able to grow veggies all winter .

I have turned an old 12'x12' shed into a green house. The super structure (rafters,studs and plywood floor) is covered with 6mil plastic. I am using a 1500 watt electric heater and another heater that looks like a radiator and is filled with oil the is heated, also using 1500 watts. I have plenty of wood to use as alternate heating. I would like to have an outside wood stove and convert a bathroom exhaust fan to blow the heat in. The power for the blower will be supplied by my 45 watt solar panel array. Any ideas, help would be MUCH appreciated.