How not to size radiators

HeatingHelp

How not to size radiators

There is a power in the way we are taught to do things when we are young that is unbelievably strong. That power can reach across the generations, and scramble our brains.

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Hvactech777

What’s the difference of sizing floor heating and cast iron radiator. We obviously size cast iron to meet with room heat lost correct?But floor heating we only heat to floor to 85 and that is comfort for us. Are cast iron radiators also convective heaters. How much convection how much radiation?

Jamie Hall

You really have to size both to the heat loss. A cast iron radiator does put out a fair amount of radiation -- but in fact much of the heat comes from convection. In a very real sense, a good bit of the heat from a "radiant" floor is convection as well...

GGross

Hvactech777 said:

What’s the difference of sizing floor heating and cast iron radiator. We obviously size cast iron to meet with room heat lost correct?But floor heating we only heat to floor to 85 and that is comfort for us. Are cast iron radiators also convective heaters. How much convection how much radiation?

@Hvactech777
You still "size" the floor heating to the heat loss of the space, ideally anyway. In the case of floor heating your "size" is essentially the supply water temperature. And yes there are times when a properly functioning in floor heat system does not meet the load of a space and we must use a supplemental heat.

EdTheHeaterMan

HeatingHelp said:

It’s just that with the Paint Method, they needed really big testing laboratories.

They could use smaller laboratories if the ceilings were lower and they used short floor painters.
You could put twice as many floors in the same hight building.