LIghting Loads

[homerphish]

When calculating the heat load from room lighting, what is the conversion from foot candles to Watts/Sq. Ft?

 

[new2hvac]

I don't believe there is an exact conversion because foot candles measure the intensity of the light and some fixtures/bulbs are more efficient than others.

 

[homerphish]

If foot candles is a measure of intensity, how can it be used to calculate lighting heat load. Wouldn't Watts/Ft^2 be the more sensible choice?

 

[MintJulep]

new2 has hit it on the head.

There is no conversion because foot candles and watts are are fundamentally different quantities.

Foot candles are a measure of lighting intensity. Watts are a measure of power.

The amount of power required to produce a foot candle of illumination is a function of the type of light source being used. There is no "global" conversion factor.