Space needed for proper convection under baseboard

Mike T., Swampeast MO

I don't know of a formula, but will confidently say, "highly significant reduction" as such will <B>greatly</B> regard convection.

[Deleted User]

Baseboard Radiation

Is there a formula to determine how much heat is being lost as a result of having wall to wall carpeting stopping the flow of air under baseboard radiators?

Any info will be helpful.

Thanks.

Unknown

was told

With cast iron base board, putting carpeting right up to it, will block 60-70 percent convection... Which is why I always install on top of 3/4 " wood strip, the carpet butt up to the strip withoout any loss of air flow.....

Brad White_9

In-ee equals out-ee

My general rule is that the inlet height should be no less than the depth of the radiation enclosure or at least the element. IOW, if you are using 4.25" square element, 4 inch is the standard height. No magic there.

As for loss of capacity, I do not know of a formula but would expect some significant differences if say 50% of recommended.

This, I suppose, can be mitigated with a taller enclosure (chimney effect). It is the chimney effect which is the motive force, secondary to the hot water which drives it initially. I would be less concerned if I had a tall enclosure versus an 8-inch high single-tier element setup.

Here is the paradox in the whole thing: Less airflow through the element means less heat transfer. This means a warmer element which means more transfer...I can envision a pulsing of heat this way. My speculation only.


I had mentioned in another post a job I did with almost full-height bookcases, a library in a home but the detail was predominant with panelling in other rooms instead of bookcases.

The chase behind in each case was the radiation convection path, single and double elements 4 inches above the floor behind the bookcases with an open toe-space for inlet. Air out the top a foot below the ceiling.

Sure the heat got into the space high (big deal you say). The airflow came out below clerestory glass all around at a high level and below any punched windows at eye level.

But any wall cavity that warm (tuned to be near room temperature using reset) would stop space heat loss cold. And it works. Eliminate the Delta-T, eliminate the heat loss.... And NO lack of convection even at low temperatures. You can feel it.

Unknown

I remember a job we did .........

A radiant to baseboard heat conversion in a leaky Levitt home . In a home for an " Engineer " . We always put the baseboard up first , and always lift it up 1/2 inch or 3/4 pipe size . This job we used 1/2 inch .

After it's all up , the " Engineer " went nuts . He blew a gasket because we lifted it that 1/2 inch . We explained we do this in case he decides to replace the floors or if a carpeter choked down the airflow . Nope , no good - he tells us the baseboard heat company would specifically state to do that if it was needed to be done .

Sooooo..... over 100 feet of baseboard had to be dropped the 1/2 inch to the floor . Since then we always ask to raise the BB .

I don't want to sound like I dislike egineers , my dad is one . But THIS particular engineer drove me crazy . It was more work for us and for his benefit . Same guy did his own heatloss and INSISTED on a boiler at least 3 times the size he needed . Right in the kitchen . I was kinda glad the thing was so loud you couldn't think straight while it ran .