Hvac Return Vent Sizing

It s a 1600 cfm system with 200 cfm of outside air 200 1600 12 5 of outside air.

Hvac return vent sizing.

This pulls the air across your body. The dimensions that suppliers and manufacturers list when talking about hvac registers is the size of the vent area not the size of the plate area. Calculate the return duct size based on the air conditioner s size and the type of duct you are using. Use the following formulas.

You determine a return grille pressure zone required 340 cfm of return. 4 tons x 144 square inches return air duct in square inches. Do this by multiplying 2 5 x 144 360 square inches. 400 fpm is the median air speed for this calculation.

Convert this measurement to inches. When people are building homes and apartment buildings they are buying both. I want to find out if i need to tell whichever hvac company i hire to replace my ac to just replace the return grills or add another vent. Size of air conditioner example.

We are after the ability to move 980cfm so you now divide this number by 400 fpm yielding 2 45 or 2 5. 340 cfm of return air x 87 5 298 cfm. Particle diameter opening size. You may round this number off to 300 cfm.

Ceiling and some sidewall registers will usually just be described as long side first such as a 10 6 or 12 8 but that can vary from brand to brand. This means that floor registers will often be smaller number first like 4 10 or 4 12. The most common point of confusion about hvac grilles is how they are measured. Trying to find the right hvac register for your project.

If the supply ducts are in the floor then the return air should be located up high. Supply air from furnaces and air conditioners should be on outside walls. Particle diameter strainers and filters mesh size vs. Ventilation systems for ventilation and air handling air change rates ducts and pressure drops charts and diagrams and more.

Air intakes and outlets ventilation systems air intakes and outlets rules of thumbs. Take 100 12 5 to find a multiplier of 87 5. I have not yet found anyone i trust to tell me what to do. Yes it is pretty simple but also essential for clear communication.

A return air grill should be sized for an air speed of 300 500 fpm feet per minute.