Boiling water is a great tip! I’d forgotten that one. It really helps to warm up the kitchen.
One winter, years ago, my hubby & I moved into an apartment building but the electricity was off in our unit. It was a Friday, we had to wait until Monday for the power company to turn on the power & heat. To stay warm, we ran the hot water in the shower - steam from the bathroom heated the rest of the small apartment quite well... :)
If you know in advance there is a chance of a winter power outage, get the makings for a big pot of stew or homemade soup. It will warm the house and smell heavenly. And you can add a little more water if you need to feed some hungry strays.