I hate when the power goes off

Question; How long do those thermal heat-packs last unused? I might get some (brand recommendations, anyone?) to keep on hand just in case.

Thanks!

See, if you lived here, you could just stick them out in the snow. :) But as for the heating the house, I strongly recommend a gas heater or woodstove that you can use in the event the power goes out. We just got one, and it is a complete relief to know that we are covered if the power goes out.