20# Gas Bottle

We have gone  2 weeks + on one tank using the furnace when night temps are in the high 30's to mid'40's and keep it at 70 in the evenings until bedtime.  During the day we set it at about 50 since we are out hiking so minimal use during the day, at least I think so, not there to monitor that.  Also run fridge and HW as well.

In the 50's to 40's (cool to cold) and with the refrigerator running, expect several days. With the 40's to 30's, it will also be multiple days. When you get down into the single digits, expect 2 or 3 days if you compromise on the temperature and set it back a few degrees.

The refrigerator itself uses very little propane. You could run for weeks on one tank for the refrigerator alone. The furnace and water heater are your biggest users of propane. Even the range is not too bad as you would most likely not be cooking for several hours at a shot with both burners on high.