Heating system sizing.
Is it possible to calculate the size of a heating system based on past energy usage? I’m working with a customer that I think their heating system is much larger than it should be. The average hourly BTU usage of the home was 28,000 BTU’s for the time period of December 27th thru January 26. He has an electric boiler rated at 27 KW, producing around 92,000 BTU’s. Weather data for this time period was 1810 heating degree days, average mean temp of 6 degrees. The location is zone 7, northern Minnesota. I believe the design temp for my area is -19.