Residual heat from boiler and radiator piping

Robert_H

With the new system I was planning to put an old cast rad in the basement to supplement the heat. But in sizing it I was wondering how much the boiler and piping are going to contribute to the warmth of the basement. This might be a stupid question but, Could I leave the radiator out and the system would respond to the heat loss through the PEX.  As we have always heated with wood in this house I have no feel for how much residual heat a boiler/piping put out. The basement is just for storage and I have a workshop down there.



House 42k

1st floor 19k

2nd floor 9.7k

Basement 13k



The first floor radiators are all piped through the basement (home run) with 1/2inch fostapex.  About 220 ft total.

The boiler is a Vitodens 200 B2HA-19 running continuous on ODR. Radiators are on TRVs.



Is it worth considering or is it  negligible?



I assume it could be calculated but am not sure where to start.



Thanks

Robert

Jamie Hall

Yes, it can be calculated... but...

It's not that hard to calculate, actually.  Half inch pipe is more or less 1/8 square feet of radiation equivalent per foot of pipe.  Give or take.  So your 220 feet would be somewhere around say 25 square feet of radiation, equivalent.  Perhaps, at a reasonable home run temp, around 2500 BTU lost.



Which is trivial.



So is the heat lost to the area from a modern boiler -- they are designed, no surprise, to put as much of the heat as possible into the circulating water!



So my suggestion would be to not worry about it and put a decent sized radiator in there with its own TRV.

Robert_H

Thanks

Thanks Jamie, that makes good sense.

Robert