Asked by: Segismundo Millares
asked in category: General Last Updated: 6th June, 2020

What size return grill do I need?

A return air grill should be sized for an air speed of 300-500 FPM(feet per minute). 400 FPM is the median air speed for this calculation. We are after the ability to move 980CFM so you now divide this number by 400 FPM yielding 2.45 or 2.5. Convert this measurement to inches.

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Similarly, it is asked, what size should the return air grill be for a 5 ton AC unit?

grille has 500 square inches of gross area (500 x 2 cfm= 1,000 cfm). Using this approach, two 20-in. x 25-in. return grilles will be the right choice for a five-ton HVAC system in order to actually deliver 2,000 cfm back to the blower without causing the return to hemorrhage.

Similarly, how do you increase return air flow? 3 Simple Ways to Improve Your Furnace's Airflow for More Comfort

  1. Unblock and clean your vents. Here's a super easy way to increase air flow.
  2. Change your filters and clean your return grill. A dirty air filter impedes air movement and makes it hard for your furnace to work efficiently.
  3. Seal leaky ductwork. Snap on some goggles and a dust mask, it's time to check out your air ducts.

In this regard, how do you size a fresh air intake?

Simply select the type of building you are considering adding fresh air to, and estimate the typical number of people occupying the building. Multiply the number of people by the required cfm per person to determine the required fresh air flow. Building use and required fresh air (in cfm) per person: Homes 5-15.

Can you have too much return air?

While there is no such thing as too much return air for the equipment (actually, there is, and it causes fan cavitation, but very rare), this CAN be an issue for the house. It has the potential to throw off pressures in different areas of the house.

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