Does anyone know if they make a ventless heater for a greenhouse?
Mine is a 30 x 85. I'm heating with propane and it is vented out which means I'm losing about 40% of my heat. I know the humidity would increase but I have circulating fans.
Not sure if a ventless would kill my plants or not?
Any ideas?
Pam
Pam how do you figure that 40% of your heat is lost?? Vented heaters just bring air to the unit so it can burn the flames.
Ventless heater would not kill your plants but if your greenhouse is air tight your unit would probably snuff out after a few hours. I have one and that is what happened often. I stopped using it this year for that reason. Switched to a kerosene heater (not vented) which doesn't burn as much oxygen.
MollyD
Vented heaters are clearly less efficient. The thing is that there is really no such thing as an unvented heater. So called unvented heaters still need an oxygen supply to burn cleanly. They rely on infiltration or some other outside air source, generally 1 square inch per 2000BTU. They can produce toxic gasses like ethylene or CO or sulfur dioxide which can be harmful to plants.
A friend of mine over the 'net is an international greenhouse consultant. He travels Central America, Eastern Europe and elsewhere helping people design greenhouses for vegetable production. His feeling is that you should never, ever, use an unvented heater. He has seen entire crops lost to these heaters. OTOH, I know of several hobby GH folks who have used unvented heaters for years without any trouble and they swear by them. Google vented and unvented heaters and you will get to read both sides of the issue.
SB
SB I bet it depends on what you are trying to grow. Vegetables may have entirely different requirements from ornamentals.
MollyD
Thanks ya'll for the advice, just wanted to see if there was another way of doing this. My gas bill is really high, just trying to save money, but don't want to harm my plants. Worked to hard to keep everything going. Maybe I'll make enough money and the gas bill won't matter.LOL
Pam
