Originally Posted by
Don Abele
Craig, here in New England the winters are pretty cold as well. I have an electric heater (Farenheat) that works really well. But it does take a little while to get things up to a workable temp. With the price of electricity, I stopped running it continuously and let the shop just cool to ambient temp.
So I started using a propane fired heater (100,000 btu). It would warm the shop up in no time, then the electric heater would continue after that while I worked out there. I tried a kerosene heater at first but didn't like the smell so it went back.
Indoor rating or not, you have to make sure your shop is well ventilated. Propane, when burning correctly, produces carbon dioxide as a byproduct. When it isn't burning correctly, it produces carbon monoxide. Both are deadly in high concentrations - carbon monoxide at much lower levels.
Kerosene, on the other hand, always produces carbon monoxide and can also produce acidic vapors (read, not good for metal). It amazes me that these are still rated for indoor use.
The other thing to remember is that both produce MASSIVE amounts of water vapor. A pound of propane burned puts about pound of water vapor in the air and a gallon of kerosene releases roughly a gallon of water vapor. I didn't notice it while it was running, but when the shop cooled off, I'd have condensation everywhere, not just on the metal surfaces. This is the reason that I no longer use it in the shop!
Just as a comparison...natural gas produces about the same amount of carbon dioxide but only one quarter the water vapor as propane.
Be well,
Doc