8x14 Metal Wall Vents: Free Area, Airflow and Duct Fit
A 8x14 wall vent has a free area of 34.6 square inches and a calculated airflow of 120 CFM, and it drops into a duct opening of 196.9 x 349.3 mm.
- Duct opening
- 7.75″ × 13.75″
- Metric
- 196.9 × 349.3 mm
- Best free area
- 34.6 sq in
- Comes in
- Flush Wall · Framed Wall
8x14 is the first size in the wall line to clear 100 CFM on our 500 fpm calculation, at 120, and its 34.6 square inches is 72 percent more than the 6x14's 20.1, which is why it turns up on larger room supplies and on return-air openings.
Free area and airflow at this size
| Product | Free area | Open | Airflow | Price | |
|---|---|---|---|---|---|
| Flush Wall Vent [Metal] | 34.6 sq in | 30% | ≈ 120 CFM | from $64.99 | View 8x14.25 |
| Framed Wall Vent [Metal] | 34.6 sq in | 31% | ≈ 120 CFM | from $64.99 | View 8x14 |
Free area is the open cross-section air actually passes through, not the outside of the cover. How we calculate it.
Measuring for this size
The Flush version is listed as 8x14.25 and the Framed version as 8x14, but both are built for the same 196.9 mm by 349.3 mm rough opening over a 152.4 mm by 304.8 mm tray, so order by the hole you measured and not by the label on the old cover.
Why is the Flush listed as 8x14.25 and the Framed as 8x14?
The label differs, the hole does not. Both are built for a 196.9 mm by 349.3 mm rough opening and both publish 34.6 square inches of free area and 120 calculated CFM. The quarter inch changes only the nominal face the percentage is divided by, which is why the Flush reads 30 percent open and the Framed 31.
Can the 8x14 be used as a return-air grille?
It is the first size in our wall line with the free area to be worth considering, at 34.6 square inches and 120 calculated CFM, but returns are sized by the system rather than by the cover. Have your HVAC contractor confirm the return the room needs, because an undersized return pulls noise through any grille.
Should I take the 8x14 or the 10x10?
The 8x14 holds slightly more free area, 34.6 square inches against 32.1, and 120 calculated CFM against 111. The 10x10 is the more open shape at 32 percent against 30 to 31. In practice, choose by the opening: a square hole takes the 10x10 and a rectangular one takes the 8x14.
How do I measure for a replacement vent?
Measure the duct opening, not the old cover. Pull the existing vent out, measure the hole itself across the width and the length in millimetres, and match that to the duct dimension listed on this page. Vent sizes are named for the duct, so a vent called 4x10 has a face larger than 4 by 10 inches. Measuring the faceplate is the single most common reason a size arrives wrong.
What happens if I order the wrong size?
Email support@khansupply.co with your order number and the millimetre measurements of your opening, and we will work out which size actually fits and sort out the exchange. Every Khan Supply vent also carries a 2-year warranty against defects, which is separate from a fit exchange.
What does shipping cost?
Nothing. Shipping is free on every order across North America, on a single vent and on a 5-pack alike. You will get tracking by email once the order is on its way. If a vent arrives damaged, photograph the box and the part and email support@khansupply.co, Monday to Friday 9 to 5 ET, and we reply within one business day.
Every Khan Supply vent is all metal, not plastic, and ships free across North America with a 2-year warranty. If a size is wrong, email support@khansupply.co and we sort out the exchange. Mon-Fri 9-5 ET, one business day reply.
Not sure of your size? · All sizes and free-area figures · Every size we make