How calc BTU of a baseboard section

[b gordo]

How does one calculate the heat output of a section of baseboard radiator? We are looking at alternatives but don't know "how much" we'd be losing by removing a section.

Also, the existing baseboard was installed before a wall was removed. Not sure how if what percentage of the existing BTU capacity needs to be replaced given that it is no longer a separate room.

 

[Dana]

Is it truly radiator baseboard (cast iron), or is it fin-tube convector?

Most fin-tube puts out about 500 BTU/hr per running foot of baseboard at an average water temp (AWT) of 170F (or a boiler output temp of 180F), and about 600 BTU/ft-hr at an AWT of 180F (=boiler output ~190F.) At lower temps the output is less, falling linearly with water temperature. The effects of flow matter as a secondary effect, but it's primarily about water temperature. An output chart for a typical baseboard product lives here.

Most radiator specs show output numbers at one or two AWT, one of which is typically 180F, but it's sometimes specified at entering water temperature, or at steam temperatures, so read the specs carefully.

Cast iron radiators and baseboard are often specified in equivalent direct radiation (EDR) square feet. At an AWT of 180F in a radiator you get about 170BTU/hr for each square foot EDR. It takes about 3.5 square feet EDR to equal a foot of typical ~2" square fin tube in 7-10" tall sheet metal convector housing.