
*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 19.375" x 24.375" 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"






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The 4" MERV 11 Furnace & AC Air Filter by Filters Fast® - 3-Pack is a set of MERV 11 filters that effectively reduce pollen, dust, pet dander, mold spores, dust mites and other allergens from indoor air. Removing these airborne particles can help improve allergies and alleviate sinus irritation that can cause watery eyes, itchy throat, coughing, and sneezing. The MERV 11 filter media is electrostatically charged and constructed with spun micro-fiber that also will not retain moisture, which can lead to microbial growth. Aside from the health benefits, these HVAC filters will also extend the life of your heating and cooling system by making it work more efficiently.
Note: These filters do not contain fiberglass.
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 | 15.375x19.375x3.625 | PF11.0416203PFF |
16x25x4 Air Filter | 15.375x24.375x3.625 | PF11.0416253PFF |
18x24x4 Air Filter | 17.375x23.375x3.625 | PF11.0418243PFF |
20x20x4 Air Filter | 19.375x19.375x3.625 | PF11.0420203PFF |
20x24x4 Air Filter | 19.375x23.375x3.625 | PF11.0420243PFF |
20x25x4 Air Filter | 19.375x24.375x3.625 | 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.
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?
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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
Compatible Parts:
The 4" MERV 11 Furnace & AC Air Filter by Filters Fast® - 3-Pack is the correct replacement for the following part numbers:

Customer Reviews:
It is a good product for my forced air heating.
Collected by Trustpilot.comRecommend by manufacturer
Collected by Trustpilot.comComes delivered to my home and does a good job.
Collected by Trustpilot.comAll good, will provide farther information after use.
Collected by Trustpilot.comworks well for me
Collected by Trustpilot.comGood filters.
Collected by Trustpilot.comReally great price and is exactly what I need for my Air Handler
Collected by Trustpilot.comHard size to find locally 16x20x4! They fit perfectly in my air handler up in the attic and 2 spares for later.
Collected by Trustpilot.comGreat value and convenient to order online. No guessing what you might find in a box store.
Collected by Trustpilot.comDoes the job well.
Collected by Trustpilot.comThe filters work nicely, fit as expected and were delivered quickly.
Collected by Trustpilot.com..........
Collected by Trustpilot.comI change my filter quarterly, necessary or not, so it is good to have a "case" of filters from Filters Fast on hand.
Collected by Trustpilot.comCorrect filters fit perfectly.
Collected by Trustpilot.comFast Affordable & Quality
Collected by Trustpilot.comThey didnt fit! not even close to the right size - much smaller in all dimensions and wont fit in the slot in my AC unit.
Collected by Trustpilot.comHelps out with my alergys. We have dogs and you can't tell by the smell. Last 3 month for me. I change the filter may work longer for most people
Collected by Trustpilot.comThey filter heater and air utility very well, however, I never thought I’d pay $95.00 for basically a paper and cardboard product. Times are a changing…
Collected by Trustpilot.comSlightly smaller than original.
Collected by Trustpilot.comLove the filters we use, good price and quality, with fast service. We'll be ordering again from this wonderful company
Collected by Trustpilot.comProduct Availability
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