Well, we got 36" + of snow yesterday, and im surprised we did not loose power. I am not a good boyscout so i was not prepared if it did. I purchased a modified sine wave 600w inverter, a 90 ah deep cycle marine battery, and a auto top off/float charger that can be plugged in constantly to the battery. The Harman XXV draws 180w continuous power, which is ~1.5 amps. This set up should give me 60-70 hours of backup heat. (i hope)