How do you size a return air grille?

How do you size a return air grille?

To calculate return air grille size, take the CFM of the HVAC unit and divide it by 350 to get the grille area in square feet. Next, multiply the grille area by 144 to convert it into square inches. Finally, choose your preferred grille size that matches the required grille area.

How big do return air vents need to be?

A typical supply vent is 4 by 10 to 12 inches and a typical return vent is 16 by 20 inches or larger. Houses often have two or more return collecting points, each with a filter, which join before re-entering the heating unit. Two-story houses will have one return downstairs and another upstairs.

Does return air grille need filter?

If there is no air filter at your HVAC unit, then you absolutely need a return vent filter. We recommend using a MERV-5 to MERV-8 pleated air filter in your return vent. So it will serve as the only line of defense against dust and particles entering your HVAC system.

What size return do you need for a 5 ton unit?

x 25-in. Return grilles are the best choice for a five-ton system in order to deliver 2,000 cfm back to the blower without causing the return to hemorrhage.

What size return do I need for a 3.5 ton?

Electric heat pumps shall be tested in accordance with UL 559 or UL 1995. Example: 3.5 ton heat pump. The duct for this system must be sized by using 6 square inches of clear duct area for each 1000 BTU of cooling. Each ton of cooling contains 12,000 BTU.

Can air return too big?

Can an air return be too big? No, an air return cannot be too big, except in extreme cases where a closed room is temporarily under negative air pressure. Return vents maintain air pressure, filter out debris, and are critical to the efficient operation of any HVAC system.

How do you clean air return vents?

Fill your sink or tub with a solution of dish soap and hot water. Immerse the vent cover in the soapy water and leave it to soak for about 20 minutes to loosen stubborn dust and grime. Remove the cover from the water and scrub both sides with a damp cloth.

Should return vents be open or closed in summer?

Open High Returns in the Summer Hot air rises and cool air sinks. Therefore, opening the right return vents in the summer and winter significantly improves the distribution of air by your forced-air system. In the summer, open your high returns and close the low ones.