How to keep pets warm during an emergency in the apartment.

I have cats and dogs and live in a horribly insulated apartment. I was wondering how to keep them warm during an emergency where we are stuck in the building.( As our apartment is surrounded by two rivers)

I have covered their emergency cages with material to keep them warm

Also how do you guys stay warm in an apartment if the power gets knocked out?

Thanks.

by Xaxaxa456