Re: Potential heat source?
Depending on how long you can expect an outage to last - we've been without power for up to four days after an ice storm - you'll either blow through a ton of hand warmers, or you'll need a better way to generate emergency heat. A small propane stove, used outside, may prove better for warming water for heated bottles, light cooking, making coffee, etc.
Or you can just get a generator. It's a PITA storing the thing but it's more than paid for itself in the last few years when I think of what could have been lost.
Re: Potential heat source?
I just lost power for about 18 hrs. Good thing I picked up a 5kw honda generator. Worth every cent of the 650$ I paid as my collection would have been ice cubes.
Re: Potential heat source?
There is no appropriate place for hand warmers in any aspect of reptile keeping, emergency or otherwise. They get exceptionally hot and have a short duration. They are simply dangerous to the health and well being of your animals.
If you want an emergency pack, use a 72 hour shipping heat pack. The heat packs of 40+ hours have a better temperature profile, and are going to give you a usable duration. You can keep one or two ten packs on hand at a pretty economical price.