You can always build a fire outside and can over it if you're not pressure canning. That's the only way my Aunt used to can.
I am thinking of using the stove in the Travel Trailer to keep the extra heat out of the house.
Or you could use the side burner on your BBQ grill if it has one. ............we used to live in a trailer with a window unit AC that didn't work the greatest....when I canned, it would get well over the one hundred degree mark INSIDE!
Those nice jars of tomatoes and salsa and corn, etc. sure look good in the winter! It's great to know what is really going into your food and to be able to control the salt. :D