Well I didn't make it to the store to get candles until it was late and then had to work some more when I got back, so the test will have to wait until later today.

I did however get a chance to build a little heater like you described using rocks and a radiation shield and it worked great. A huge amount of the heat was stored by the rocks.

The top of the rocks peaked at about 117º after about 30 minutes and anywhere else you could touch the heater was cooler than that. Plus, the rocks stayed warm for quite a long while after I put out the candles. They were still emitting a lot of heat well over an hour later. That's an ingenious suggestion that provides a huge plus. Thanks!!!





On my tent neither the front door panel or the floor are sealed at all. The air will exchange pretty often through convection alone.



By comparison my tent is pretty small inside. About 80 cubic feet.

BHZ is can explain this better than I, but here's the theory I'm working with:

The candles produce radiant heat and the tent material is designed to reflect that radiant heat back inside the tent. Radiant heat works good for warming "stuff", like sleeping bags and people and rocks, but it doesn't warm air very well at all. So, in theory, my bag will be about the only "stuff" inside my tent to absorb that heat and should be warmer than the inside of the tent because everything else reflects the heat and air doesn't have much in it to absorb the heat.

Heating the rocks with the candles stores the radiant heat. Once the rocks are heated they start transferring their heat by radiating it to any stuff around that's cooler than they are. Hopefully lots of their heat will make it into me and my sleeping bag long after the candles are extinguished.

Here's a photo of the tent. It's simply made with SOL emergency blankets with the reflective surface towards the inside of the tent.

I'll let you know if it works as soon as I can...