How big should my return air grille be?

General rule is 1 sq ft of return grille per 200 CFM of airflow. A 3-ton system needs about 600 sq inches of return.

Should I use a filter grille?

Filter grilles are convenient but must be changed regularly to avoid restricting airflow.

Return Air Grille

HVAC & Ventilation

Registers & Grilles

Budget: $5-$12 (stamped steel, no filter) | Mid-range: $15-$30 (filter-back grille) | Premium: $30-$60 (decorative or custom)

Return Air Grilles: HVAC Return Vent Covers for Balanced Airflow (2026)

Prepared by Lumberama's Building Materials Team

|Last updated May 25, 2026|Sources & methodology

Return air grilles cover the openings where room air is pulled back into the HVAC system for reconditioning. Unlike supply registers, they typically have fixed louvers and no damper. Filter-back return grilles hold a standard furnace filter to improve indoor air quality.

Key Features

Fixed louvers for unrestricted return airflow; Filter-back models hold standard HVAC filters; Large sizes for adequate return capacity; Steel or aluminum construction; Easy screw-mount installation

Specifications

Common sizes: 14x20

20x20

20x25

24x24

30x14 | Materials: stamped steel

aluminum | Finish: white powder coat standard | Mounting: screw-in frame | Filter compatible: 1" standard filters

Applications

Central HVAC return air intake; Filter grille for air quality improvement; Wall-mounted return vents; Ceiling return air openings; Hallway and common area returns

Installation Overview

Position grille over return air opening and secure with screws into the frame or drywall. For filter grilles, insert a standard 1-inch filter behind the grille face. Replace filters every 1-3 months.

Pros & Cons

Pros

✓ Simple installation; Filter models improve air quality; No moving parts to break; Large selection of sizes

Cons

✗ Fixed louvers offer no airflow adjustment; Can be noisy if undersized; Limited decorative options; Must be kept clear of obstructions

Top Brands

Accord

TRUaire

Hart & Cooley

Code Requirements

Return air capacity must match HVAC system CFM requirements. Cannot draw return air from bathrooms, kitchens, or garages per IRC M1602. Must be sized per HVAC design manual.

Buying Tips

Oversize your return grille when possible to reduce noise and static pressure; Filter-back grilles are convenient but check filter size availability; Match the finish to your supply registers for a consistent look