Lennox Healthy Climate X6670 & X6673 Filters: Sizes, MERV Versions and Part Numbers
Quick answer
The X6670 fits the HCC16-28 cabinet (nominal 16x25x5, actual 15¾ × 24¾ × 4⅜ in). The X6673 fits the HCC20-28 (nominal 20x25x5, actual 19¾ × 24¾ × 4⅜ in). Both are MERV 11. [S1]
- Same cabinets, higher MERV: 19L16 / 19L17 (MERV 13) and X6672 / X6675 (MERV 16, Carbon Clean 16). All are the same size. [S1]
- Lennox estimates a service life of up to 12 months for these box filters. How long yours lasts depends on things like household size, pets and lifestyle. [S1]
- These are 5-inch-class filters. A standard 16x25x4 or 20x25x4 (about 3⅝–3¾ in deep) is a different size. [S1] [S2]
Replacement filters by cabinet
| Cabinet | MERV 11 box filter | MERV 13 box filter | MERV 16 box filter | Nominal | Actual size (in) |
|---|---|---|---|---|---|
| HCC16-28 | HCF16-11 → X6670 | HCF16-13 → 19L16 | HCF16-16 → X6672 | 16 x 25 x 5 | 15¾ × 24¾ × 4⅜ [S1] |
| HCC20-28 | HCF20-11 → X6673 | HCF20-13 → 19L17 | HCF20-16 → X6675 | 20 x 25 x 5 | 19¾ × 24¾ × 4⅜ [S1] |
"HCF" is the filter model; the X/19L number is the replacement part Lennox lists under maintenance supplies. [S1]
Expandable filter kits (reusable frame)
Airflow and pressure drop (Lennox's figures)
How to confirm which one you need
- Read the cabinet. The HCC model number tells you the size: 16-28 means a 16 x 25 filter, and 20-28 means a 20 x 25. [S1]
- Read the old filter. An HCF number ending in -11, -13 or -16 gives the MERV rating. [S1]
- Pick a MERV rating. Lennox lists MERV 11, 13 and 16 filters for both cabinets, all the same size. [S1] If you're moving up a rating, ask your HVAC dealer. Lennox says these systems are usually maintained by professionals. [S2]
Where to buy
We don't link to specific sellers here yet. Search for the exact part number or size on this page at a retailer you trust, compare the listed actual dimensions, and check the current price. We don't list prices because they change daily.
FAQ
What size is a Lennox X6673?
Nominal 20 x 25 x 5, actual 19¾ × 24¾ × 4⅜ inches. It's the MERV 11 box filter for the HCC20-28 cabinet (filter model HCF20-11). [S1]
What size is a Lennox X6670?
Nominal 16 x 25 x 5, actual 15¾ × 24¾ × 4⅜ inches. It's the MERV 11 box filter for the HCC16-28 cabinet (filter model HCF16-11). [S1]
What's the MERV 13 version of the X6673?
Lennox lists the HCF20-13, replacement part 19L17, for the HCC20-28 cabinet. The HCC16-28 equivalent is 19L16. [S1]
How often should I change a Lennox Healthy Climate filter?
Lennox estimates up to 12 months, depending on factors like the number of people in the home, pets and lifestyle. [S1] Lennox also says advanced filtration systems are usually maintained by HVAC professionals. [S2]
Which way does the arrow go?
Lennox says the arrows on the frame show airflow direction and should point toward the furnace or air handler. [S2]
What we could not verify
- Third-party "X6673 replacement" filters. We haven't checked any against Lennox's dimensions yet.
- Air-handler cabinets (HCC08-21, HCC10-22, HCC19-22, HCC19-25). Lennox's sheet lists them, but parts of that table didn't extract cleanly, so we left them out. See the 20x20x1 guide for the HCF14 filters.
Sources
- [S1] Healthy Climate HCC Media Air Cleaners product specifications (Form 210450, February 2026) — Lennox Industries. Accessed 2026-10-24. Used for: All part numbers, sizes, airflow, pressure drop, service life.
- [S2] Air Filters — Lennox Residential. Accessed 2026-10-24. Used for: Advanced systems maintained by pros; arrow direction.
Last checked 2026-10-24. Spot an error? Tell us and we'll recheck it against the source.