Middle of June we went to Benezette, PA for a long weekend. Weather was wet, then great. Except it got pretty chilly at night, as in low 40s chilly. No problem says I, we have a camper now instead of a tent so I'll turn the heat on. Clicks right on, heats up nice. For about 5 minutes, then the smoke detector starts going off. Odd, as I didn't see any smoke but did smell a bit of "new" burning off the heater as it's never been on before. I pulled the smoke detector battery and let the heat run for about 10 minutes to get the chill out of the camper. Got the electric mattress turned on and warmed up (life saver right there) and went to sleep. Before going to sleep I turned the furnace off and put the battery back in the detector, because I didn't really trust it to run while I was sleeping. I did have a couple of the windows unzipped just a few inches to keep some fresh air coming into the camper. My theory is that since we hadn't used the furnace before that there was some residue or something burning off. I know that the new detectors don't need to "see" smoke and that is what was going on. Thought I'd post up here and see what those that have more experience thought about this. I don't want to freeze, nor do I want to leave the battery out of the detector and wake up dead from some sort of new furnace poisoning. As that would surely ruin my camping trip. And if you can use an electric mattress in your pop up, get one. They are great, we would have froze without it.