Running furnace on 12V battery

Last night winds really picked up and temp dropped 25 degrees in a couple of hours. We got a few inches of snow and around 9:00 the power goes out. The furnace was about 1/3 full and after a long day working in morn and hunting in afternoon I was dreading getting all dressed back up to go to the shop to get the generator. I always have a couple of fresh charged batteries in the mud room (just in case, with all the equipment I have) and I knew I had an inverter somewhere. Unplugged furnace from wall , into inverter and hook clamps of inverter to battery. Presto,,,,, temporary furnace power. Power was out for 3-4 hours and the battery/inverter worked great. I think I'll use this setup if the power is out for extended periods and not run generator all night, then during the day I can run generator to cool fridge/freezer ,run water pump, do laundry, etc, and recharge battery for following nights furnace power. It wood save a ton of fuel ,after all what do you need all that power for at night anyway.

Sorry guys posted in wrong room.