Got the 1st gas statement that was a full month running on this insert. Cut the bill by 75% compared to last year and the temps according to the gas company were 8 degrees colder on avergae this year. I am still running the furnace to take the chill off in the morning and I have gas HW and cook stove so I still used a bit of gas. But a $50 gas bill in winter has me stoked!