Propane is the same gas used for furnaces, gas stoves and indoor and outdoor fake gas fireplaces. Energy efficient appliances burn propane pretty clean as far as I know. It may depend on the lantern you choose. Talk to your gas company.

Propane is relatively expensive in most areas, and often comparable to fuel oil in cost, so natural gas is usually considered to be the cheapest fossil fuel. Propane also releases moisture while burning, so it can raise the humidity when used to heat a garage or other small space. However, I've never heard it categorized as being "dirty."

Bruce

Expert chiming in! You know, on occasion I also tell my clients "propane burns dirty." I have no idea why I say that, and really no proof of it. I have sold 10,000's of propane gas lanterns and maybe once every 2 years someone has an issue. With our gas fixtures, the fix is just to increase the small holes in the bottom pan of the light fixture to allow more oxygen to get to the burner, and then the sooting stops. We'd love to help!

Be careful re adding holes! Propane is heavier than air and has no smell - so it can sink to the ground and collect there without anyone noticing... That's the major reason for the fire hazard when propane is used.

"Your homeowner's insurance would go "through the roof."

A bit of hyperbole? I think ours went up by $8/mo for 6 of them on our porch.