It is a 15kw generator, it burns about 1.7? Gallons per hour running. Doesn't seem to matter about load. In our case, it was winter, nothing to do without power. I sat played on TBN while my wife was at work. I shut it off about 10 pm every night, but the house was getting cold by 6 am. I tried to leave for 4 or 5 hours some days, but that wasn't a option some days. The furnace was running also, the temps were down to -15F. Thinking about it, I need to ad a few days of outage in November to the propane use. I am glad I have the unit, but I hope to never go thru this crap again. After the winter we had, 2 of my neighbors sold their homes and moved into town. 6 days in November and 7 days in December without power was too much for them. I am thinking of getting a 10 kW generator as a back up to the backup. If you wait to the power to go out, you usually can't buy one.