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Combustion Air Calc

Kjmass1
Kjmass1 Member Posts: 292

We recently tightened up our basement so we needed to install a Fan in the Can for makeup air- man is that thing loud, right under our living room. I'm wondering if we could have gotten by with a fully louvered door instead. Am I reading these calculations correctly for a 125K steam boiler and 40k HWH gas?

165K of input requires (2x) 165 square inches of free area, within 1' of ceiling and floor. Roughly 13"x13" each without obstructions.

I have a utility door that would provide access to the entire basement, 28" x 78", 2184 square inches. I read this as I need 330 square inches without obstructions, or 15% of the door to net this amount of free area. Is a wooden slat door in that ballpark? Hard to find any info on this.

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