hydronic baseboard BTU calculation based on water temperature

nuheat

Hydronic baseboards are rated at a certain BTU e.g. 330BTU/ft. But at what water temperature is the BTU rating (180F?). If I change water temp to that of a regular water heater e.g. 110 then what does the BTU rating change to? Is there any formula to calculate?

EBEBRATT-Ed

I would call the manufacturer of the baseboard you want to use. You need to know the approximate flow rate of the water and what your temperature drop will be.

for instance most 3/4 fin tube with 180 average water temp will be around 550/foot with a 20 degree TD 190 supply 170 return 180 average water temp.

You need the above information to get an accurate answer on your application

nuheat

Manufacturer unresponsive. This should be independent of manufacturer and can be calculated just based on Physics.

bburd

Most radiation manufacturers’ websites include a derating chart to show the output at various water temperatures. Here is one from one of the more popular manufacturers:

https://www.slantfin.com/images/stories/Technical-Literature/ratings_fineline30_r.pdf