brckwlt wrote:How big is your house.
is the 25lbs during the summer for hot water or do you mean on mild winter days?
Heating about 1800 sq. ft. on four zones. Well insulated with double glass windows, about half argon filled. Also sometimes heat a 1000 sq ft shop. 25 lbs in a mild winter day, i.e. no wind, sunny and above freezing for the entire 24 hours. Summertime domestic hot water is also about 25 lbs a day, maybe a little less. It's high because I have a lot of piping loss between the boiler and the indirect hot water heater plus the idle fire losses.