Can you put a HEPA filter in a furnace?
Short answer: Usually not. True HEPA filters are dense and most residential furnaces and air handlers are not designed for the airflow resistance, so a HEPA filter does not fit a standard 1-inch or 4-inch slot. Whole-house HEPA is normally a separate bypass unit with its own fan. For a standard system, EPA suggests MERV 13, or the highest rating your system can handle.
Options that fit a normal filter slot
- MERV 13 filters in your existing size; check that your system can handle them.
- Deeper 4-inch media cabinets, which give more filter area at a given rating.
- Portable HEPA air cleaners for individual rooms.
If your equipment manual lists a maximum filter rating or pressure drop, follow it, or ask an HVAC technician.
MERV 13 filters
- 16x25x1 Merv 13 Universal Air Filter By Tier1 (Single Filter) — $53.74
- 16x25x1 Merv 13 Universal Air Filter By Tier1 (6-Pack) — $81.15
- 16x20x1 Merv 13 Universal Air Filter By Tier1 (Single Filter) — $53.74
- 16x20x1 Merv 13 Universal Air Filter By Tier1 (6-Pack) — $77.21
- 20x20x1 Merv 13 Universal Air Filter By Tier1 (Single Filter) — $53.74
- 20x20x1 Merv 13 Universal Air Filter By Tier1 (6-Pack) — $83.55
Common questions
Is MERV 13 the same as HEPA?
No. HEPA is a separate, higher efficiency standard. MERV 13 is a high rating on the ASHRAE 52.2 scale used for HVAC filters.
Will a MERV 13 filter hurt my furnace?
In some 1-inch slots it can add noticeable airflow resistance. Check your equipment maker's guidance or ask a technician.
Do you sell HEPA filters?
We don't have priced HEPA cartridges right now. We list HVAC filters up to MERV 13.
Shop HVAC air filters Choosing a MERV rating
Related categories: HVAC Air Filters. General information only; follow the equipment maker's instructions and local codes. Updated 2026-11-14.