Lennox Air Filters: Sizes & Replacements
Quick answer: Lennox Healthy Climate cabinets (HCC16-28, HCC20-28) take X-series 5-inch media — our "LXRED" line is sized for those cabinets. Lennox furnaces without a media cabinet take standard 1-inch sizes at the return.
Lennox model directory
| Model / part | Filter size & fit | Guide |
|---|---|---|
| X6672 | 16x25x5 (HCC16-28 cabinet) | Replacement guide |
| X6673 | 20x25x5 (HCC20-28 cabinet) | Replacement guide |
| X6675 | 20x25x5 MERV 16 (HCC20-28 cabinet) | Replacement guide |
Lennox filter FAQ
What size is a Lennox X6675 filter?
Nominal 20x25x5, actual about 19⅞ × 24⅞ × 4⅜ inches. It fits the Lennox HCC20-28 Healthy Climate cabinet. X6673 is the same footprint; X6672 is the 16x25x5 version for HCC16-28.
Do I have to buy Lennox-brand replacement media?
No. Any media cut to the X-series footprint fits and seals. Our LXRED line matches the X6672/X6673/X6675 dimensions at a fraction of OEM price, in MERV 8 through 15 with carbon options.
How often should Lennox media filters be replaced?
Every 6–12 months, sooner with pets, allergies or smoke events. One 2-pack typically covers one to two years.
Every Ironside filter is American-made by our manufacturing partners. Flat-rate shipping — same on 1, 2 or 3 packs. Built here. Breathe better.