I’d like to pick the brains of you HVAC guys on this one. The celing of our basement is on the low side and to make matters worse, some of the furnace ducts run perpendicular to the floor joists and therefore extend below them. Headroom is a real concern. (If I were 5’11 instead of 5’10, I’d have a sore forehead from hitting the ducts). What sort of considerations are there in going from the square sheet metal ducts in those locations to round flex? There actually is only one supply and one return to worry about here.
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Greetings Brick,
This post, in response to your question, will bump the thread through the 'recent discussion' listing again.
Perhaps it will catch someones attention that can help you with advice.
Cheers
'Nemo me impune lacesset'
No one will provoke me with impunity
Going from square to round isn't going to do much for you, especially if you're talking about using flex. What you can do is use a flatter rectangular duct- shorter but wider than what you have now- but you don't want the width to be more than 4x the depth. That may get you some of the headroom you're looking for.
Bob
Just out of curiosity, what is the reason for keeping the width to depth ratio > 4 provided the cross sectional area is the same?
Is it related to friction against the sides? I knw that as the difference between the width & depth increases you need to increase the perimeter to maintain the same area - which would create more interior surface.
I believe it's got something to do with turbulence inside the duct, and the noise that results from it. We've just always followed that rule (I know- just like a lemming....lol).
Bob