The only required (and possible) user input (blue fields) is:
1) Enter your homes various rooms names and their dimensions
2) Enter your local areas nominal annual heating degree days (HDD's)
3) Enter your maintained mid range boiler temperature
The spreadsheet does all the rest. It tells you:
1) Feet of fintube baseboard required per room
2) GPM of flow required in each zone to achieve a 20 degree Delta-T
3) Number of zones required
4) Boilers minimum required BTUH output
5) The progression of declining water temperature as water flows through your baseboards
6) The progression of remaining BTUH heat energy as water flows through your baseboards
Run it first for the whole house to determine your overall requirements. Then after you have all of the overall information, you can (if desired) fine tune your GPM's required for a Delta-T of 20 degrees in each individual zone by entering the zones one at a time. Just zero the dimensions for any rooms that are not on a particular zone loop to accomplish this.
The core aspects of the logic are sound, but admittedly, not all of the spreadsheet logic is correct. Some of it is empirically speculative to the point of being merely educated guess work. This is an evolving work in process. I believe that it should yield for you a satisfactory working hot water baseboard heating system though. As they say, you are getting what you pay for. All help in approving it is appreciated. You are free to modify at will.
