How to Compute Sizing Ducts for HVAC
If you are building ducts into a room of a building, make sure they are large enough to allow smooth air flow. To do so, you need to know two variables: desired air flow rate (quantity of air) and desired speed. From there, the sizing of ducts for HVAC (Heating, Ventilation and/or Air Conditioning) systems uses a simple formula. This, of course, gives you the minimum duct size. There’s no danger in creating a larger duct if you have some reason to. Does this Spark an idea?
Instructions
-
-
1
Determine how much air you need flowing through per second (in cubic yards or meters). Call this “q.”
-
2
Determine how fast the air will be moving (in yards or meters per second). The faster the air moves, the smaller you can make the duct. Call this “v.”
-
-
3
Divide q (air flow) by v (air speed) to get the HVAC duct size. It will be in units of square yards or meters. Remember that a duct is only as strong as its thinnest section, so every single inch of the duct will need to be at least this large.
-
1
