JustAHomeOwner
Member
G'day All,
My daughter and hubby have a 2 story home with one zone of hot water heat on each floor. There's no heat in the full basement. DHW is supplied with a indirect as a 3rd zone from a oil fired boiler. Using data from 12/9/13 to 4/21/14 they burned 544 gallons of fuel oil. HDD's for that period based on 65 degrees total 3881. Therm per HDD is .196, 694 BTU's per HD hour, w/ a 85 percent boiler, 99 percent temp of 15 degrees, output was 34,700 BTU's per average hour. If I multiply that by 150 percent it's roughly 52K. The part I'm unsure of is the indirect ( I'm waiting for the size from them but it's not larger then 35 gallons ) recommends a boiler size of no less then 99K. Are the specs for indirect water heaters that far off because they were warm last winter and had plenty of hot water??
My daughter and hubby have a 2 story home with one zone of hot water heat on each floor. There's no heat in the full basement. DHW is supplied with a indirect as a 3rd zone from a oil fired boiler. Using data from 12/9/13 to 4/21/14 they burned 544 gallons of fuel oil. HDD's for that period based on 65 degrees total 3881. Therm per HDD is .196, 694 BTU's per HD hour, w/ a 85 percent boiler, 99 percent temp of 15 degrees, output was 34,700 BTU's per average hour. If I multiply that by 150 percent it's roughly 52K. The part I'm unsure of is the indirect ( I'm waiting for the size from them but it's not larger then 35 gallons ) recommends a boiler size of no less then 99K. Are the specs for indirect water heaters that far off because they were warm last winter and had plenty of hot water??