In the 3 years I have had mine, it has run for a total of 65 minutes which wasn't exercise time. One time was 50 minutes, lol. Still good insurance.I am using a Generac 22kw for the whole house. It is plumbed in directly to the natural gas. It has auto switching as well. 10 seconds after power out it starts up and loads 10 seconds later. Once a week it starts up and runs diagnostics, emails results and shuts down. In the last 2 years I have used it for 12 hours or more 3 times. Well worth the investment.