BTU ratings for baseboard element

Doc Radiant

Ron, good question! Of course, the cabinet is what enhances the convection through the element, so it's safe to say that no cabinet at all is going to have a serious impact on the output.

If I was to take a WAG, I would bet it's about 50%.

Unknown

We installed a boiler for a homeowner

who was renovating the downstairs . They took out all the Slant Fin 30 covers and left only the element connected . They propped the element off the ground with small pieces of 2 by 4 to keep the heat flowing . They asked me what kind of decrease in output they might have till they can throw in new baseboard in the spring , maybe . I had no idea , but I'd like to know next time someone asks . Any ideas ? Thanks in advance .

Unknown

Ron

I took a close look at some old rating books I have for Commercial Type baseboard and convectors with 3-1/2" x 3-1/2" element and surprisingly, element with no cover is within about 95% of the output of that with cover. Sure is news to me but it was consistent between about 15 different manufacturers! Hope this helps.

Glenn Stanton

Manager of Training

Burnham Hydronics

U.S. Boiler Co., Inc.

Doc Radiant

Glenn, ditto what I just found in some I=B=R guides I have on hand. If the tube is supported the same distance from the floor as if it was in the cabinet, it does look like about a 5 to 10 percent degradation. Obviously, laying the finned tube on the floor with no air space under it will kill it's output, just like blocking the gap under the front cover of the cabinet.

BTW, you will often see at least a 5% difference in performance of the same finned tube depending on the cabinet it is installed in.

Unknown

Wow

I had no idea either the ratings would be so close with or without the cover . Thank you alot for doing the research Glenn .

Unknown

Doc

do they have any charts on performance if the baseboard is raised higher off the ground ? A crew of ours had to install some Argo with the bottom of the baseboard at least a foot off the ground . The homeowner wanted to show off his hand made trim and didn't want it blocked . Thanks for the research also Doc .

Doc Radiant

The output of baseboard...

...is based on a number of factors, including the design of the element and cabinet. The two other major factors at a given flow rate are (1) the temperature of water flowing through the element and (2) the temperature of the air entering the bottom of the baseboard. I=B=R rates baseboard with a 65 degree F. entry air temp.

At any given water temperature, output will increase as the entering air temp drops (greater delta-T). Assuming there will not be much of a difference in the temperature of the air entering the cabinet with it raised a bit higher, there should be no difference in output, though it may look a bit odd....