Lennox X6673 Replacement Filter

Quick answer: Our 20x25x5 "LXRED" filters match the Lennox X6673 footprint (about 19⅞ × 24⅞ × 4⅜ in) — a direct replacement for 20x25 Healthy Climate cabinets. Available in MERV 8 through 15, carbon options included.

Shop 20x25x5 Lennox-compatible filters →

Install in three steps

1. Slide the old media out of the cabinet. 2. Note the airflow arrow — it points toward the furnace. 3. Slide the new filter in, arrow the same direction, close the door. Done.

X6673 FAQ

What filter replaces the Lennox X6673?

Our 20x25x5 "LXRED" filters match the Lennox X6673 footprint (about 19⅞ × 24⅞ × 4⅜ in) — a direct replacement for 20x25 Healthy Climate cabinets.

How do I install it?

Three steps: slide the old media out of the cabinet, note the airflow arrow on the frame, slide the new one in arrow-pointing the same way, and close the door. No tools. Takes about a minute.

How often should I replace it?

Every 6–12 months. Deep-pleat media holds roughly a year of dust in most homes — change sooner with pets, allergies, or after wildfire smoke. Shipping costs the same on 1, 2 or 3 packs, so most customers stock 2 years at once.

American-made by our manufacturing partners. Built here. Breathe better.