As you all are aware, it will soon become winter in the northern hemisphere, and my attic where I do all my growing is not heated. I'd like to heat it, but I'm debating how to do that. First of all, I need to insulate it, but that shouldn't be hard. The attic is drafty though, and will probably still be drafty even after it's insulated. The lights will of course add some heat, but there will need to be more heat after it's turned off. My choices thus far appear to be as follows: Natural gas Propane Kerosene Electric Natural gas would be my first choice, except I would need to run a line from the basement to the attic. Not impossible, but it would need to stretch 25-30 feet and be flexible enough to bend around pipes and through floorboards. The people at the hardware store told me that gas lines should be black steel. This is not flexible at all and would be almost impossible to run up to my attic. However, most of the gas line in my house appears to be copper, so I thought I'd be able to use that. Copper line is flexible, but supposedly it's hard to add the right ends to. I might need someone to do that for me, but I definitely don't want some plumber installing a gas line in my grow room! Maybe I could have a plumber do the ends, and then install the line myself. It's too bad they don't make flexible gas line. Unless they do and I just don't know about it. Propane would eliminate the need for running a gas line to the attic, but I'm not sure how long a tank would last. If it ran out on a cold night, my plants could all freeze. I'm not sure if it would be much more expensive than gas as well. I could borrow a kerosene heater from my dad, but I don't like the idea of using one in my attic. I know they're a fire hazard, or at least more so than my other options. Electric heat is expensive and I'd have to run a new line up to the attic if I was going to use it. It's safe, but doesn't have the output to keep a room warm if it's really cold. Plus I was kind of hoping to get some elevated CO2 levels from the combustion. Right now, I'm thinking I should just work on insulating my attic. When it starts getting really cold, I'll get one of those ventless heaters that can run on either propane or gas. Then I'll hook it up to the propane tank from my grill. If I find I'm refilling it twice a week, I'll look into natural gas. Anyone have experience with this sort of thing?