*Please be advised that some larger filters require an additional cost (see dropdown window above).
- Size Actual Dimension
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12x24x4 11.375" x 23.375" x 3.625"
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16x20x4 15.5" x 19.5" x 3.625"
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16x25x4 15.5" x 24.5" x 3.625"
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18x24x4 17.375" x 23.375" x 3.625"
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20x20x4 19.5" x 19.5" x 3.625"
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20x24x4 19.375" x 23.375" x 3.625"
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20x25x4 19.5" x 24.5" x 3.625"
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24x24x4 23.375" x 23.375" x 3.625"
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25x29x4 24.375" x 28.375" x 3.625"
4" MERV 11 Furnace & AC Air Filter by Filters Fast® - 3-Pack
FF4M11
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1" MERV 11 Furnace & AC Air Filter by Filters Fast® - 6-Pack
Filters Fast® Custom Size Air Filters - Made to your size FastThe 4" MERV 11 Furnace & AC Air Filter by Filters Fast® is an HVAC air filter designed to improve indoor air quality by capturing pollen, dust, pet dander, mold spores, and other common allergens. Its electrostatically charged MERV 11 media helps reduce airborne irritants while supporting efficient HVAC system performance. Compatible with furnace and air conditioning systems that use 4-inch air filters.
Note: These filters do not contain fiberglass.
Key Benefits:
- Helps to reduce sneezing, coughing, itchy throat, watery eyes, and other allergy-related discomforts.
- MERV 11 rating provides stronger filtration than standard filters while maintaining airflow suitable for many residential HVAC systems.
- Uses electrostatic technology to attract and capture more airborne particles for improved filtration efficiency.
- Moisture-resistant media that discourages microbial growth.
- Keeps dust and debris out of heating and cooling equipment, supporting cleaner operation and reducing system strain.
- 6–12 month lifespan, reducing maintenance frequency compared to many standard filters.
Specifications:
- Brand: Filters Fast®
- Part Number: FF4M11
- Pack Size: 3
- Filter Life: 6 - 12 Months
- MERV Rating: 11
- Filter Type: Electrostatic pleated
- Material: Synthetic
- For commercial and residential use
Available Sizes:
The 4" MERV 11 Furnace & AC Air Filter by Filters Fast® is available in the following sizes:
| Nominal Size | Actual Size | Alternate Part Number |
|---|---|---|
| 12x24x4 Air Filter | 11.375x23.375x3.625 | PF11.0412243PFF |
| 16x20x4 Air Filter | 15.5x19.5x3.625 | PF11.0416203PFF |
| 16x25x4 Air Filter | 15.5x24.5x3.625 | PF11.0416253PFF |
| 18x24x4 Air Filter | 17.375x23.375x3.625 | PF11.0418243PFF |
| 20x20x4 Air Filter | 19.5x19.5x3.625 | PF11.0420203PFF |
| 20x24x4 Air Filter | 19.375x23.375x3.625 | PF11.0420243PFF |
| 20x25x4 Air Filter | 19.5x24.5x3.625 | PF11.0420253PFF |
| 24x24x4 Air Filter | 23.375x23.375x3.625 | PF11.0424243PFF |
| 25x29x4 Air Filter | 24.375x28.375x3.625 | PF11.0425293PFF |
Custom Sizes:
- If you don' t see your size, order a custom made air filter! Custom made air filters do not come individually wrapped.
Compatible Parts:
The 4" MERV 11 Furnace & AC Air Filter by Filters Fast® - 3-Pack is the correct replacement for the following part numbers:
Compatible Models:
The 4" MERV 11 Furnace & AC Air Filter by Filters Fast® - 3-Pack is correct replacement for the following model numbers:
Frequently Asked Questions:
How do you install the 4" MERV 11 Furnace & AC Air Filter by Filters Fast®?
- Once your air filters arrive, gather your supplies including a ladder (if needed,) safety goggles, gloves, a mask, and a disposable bag.
- Remove the metal grate from your air return.
- Carefully remove the used air filter and place it immediately and gently into the disposable bag. Then tie the bag sealed.
- Place the new air filter in place of the filter you just removed and replace the metal grille.
How often should you replace the 4" MERV 11 Furnace & AC Air Filter by Filters Fast®?
Changing your 4" MERV 11 Furnace & AC Air Filter by Filters Fast® is a very quick and easy process that should be done once every six to twelve months.
What contaminants does the 4" MERV 11 Furnace & AC Air Filter by Filters Fast® reduce?
The 4" MERV 11 Furnace & AC Air Filter by Filters Fast® is a MERV 11 air filter, which means that it reduces the following contaminants:
- Dust
- Pollen
- Mold Spores
- Pet Dander
- Dust Mites
- Smoke & Smog
- Other Common Airborne Allergens
So the 4" MERV 11 Furnace & AC Air Filter by Filters Fast® can help reduce dust in my home?
Correct! By capturing airborne dust particles before they circulate through your HVAC system, this filter can help reduce dust buildup in your home and improve overall indoor air quality.
Dust levels also depend on factors like ventilation, pets, and household activity, so you may have to replace your filter more frequently based on the above factors.
Does it matter which way the arrow points?
It does! The arrow printed on the edge of the frame must point toward the direction the air is moving. Installing it backwards reduces its dust-holding capacity and can increase the strain on your system.
Can I wash and reuse the 4" MERV 11 Furnace & AC Air Filter by Filters Fast®?
No! These are disposable filters. Attempting to wash them will strip the electrostatic charge from the fibers and damage the pleated structure. This renders the filter useless and potentially allows debris to bypass the filter and damage your HVAC coils.
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