19x20x4 Air Filters

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Products   MERV Rating Filter Life Annual Cost Value Pack
19x20x4 MERV8 SpiroPure O
MERV 8 Pleated Filters (6 Pack)
    5 stars
  • $152.58
  • 6 Filters
  • ($25.43 / filters)
MERV 8
Learn more 		3 Months $101.72
Best Value!

$152.58
6 Filters

($25.43 / filter)
19x20x4 MERV11 SpiroPure O
MERV 11 Pleated Filters (6 Pack)
  • $192.67
  • 6 Filters
  • ($32.11 / filters)
MERV 11
Learn more 		3 Months $128.45

$192.67
6 Filters

($32.11 / filter)
19x20x4 MERV13 SpiroPure O
MERV 13 Pleated Filters (6 Pack)
  • $198.58
  • 6 Filters
  • ($33.10 / filters)
MERV 13
Learn more 		3 Months $132.39

$198.58
6 Filters

($33.10 / filter)
19x20x4 OdorBan SpiroPure F
MERV 10 Odor Eliminator Filters (6 Pack)
  • $258.48
  • 6 Filters
  • ($43.08 / filters)
MERV 10
Learn more 		3 Months Learn more
about odor eliminator filters 		$172.32

$258.48
6 Filters

($43.08 / filter)
MERV Rating - Contaminant Removal Guide
MERV Rating   8 11 12 13
Lint & Dust  
Dust Mite Debris  
Pollen  
Mold Spores  
Pet Dander  
Auto Emissions  
Smoke  
Tobacco  
Bacteria  
Note: equals efficient removal of contaminant by filter.

How do I choose the best 19x20x4 air filter for my furnace?

The 19x20x4 is a non-standard 4-inch deep air filter for furnaces and HVAC systems with a 19" x 20" cabinet opening. Actual dimensions are 19" x 20" x 3.5", or exactly the same width and length and generally with thickness 1/4" less for 1" and 2" filters and up to 1/2" less for thicker whole house filters. This actual width and length but nominal depth (thickness) are consistent with the industry standard across all pleated filters. All Filters carries SpiroPure 19x20x4 filters in MERV 8, MERV 11, and MERV 13. Custom-cut filters are not returnable so please confirm your measurements before ordering. Browse options below or explore our full furnace filters catalog.

How to Order the Right 19x20x4 Air Filter?

Most filters use nominal sizes, which are rounded up to the nearest inch. For example, if your filter measures 15.5" x 24.5", you likely need a standard 16x25 nominal filter. Check for a standard size first, as it is the most common way to buy.

Non-standard sizes like 19x20x4 are listed by actual dimensions. To ensure a perfect fit, you have two options:

Measuring an existing filter: Use a tape measure to the nearest 1/8" and order those exact dimensions.
Measuring the filter slot: Measure the interior opening and subtract 1/4" from the length and width. This "undercut" ensures the filter slides in easily.

Note on depth: Depth is the exception. A nominal 2-inch filter has an actual depth of 1.75" across all brands. Industry tolerance is +/- 1/8" for any dimension.

What are the best 19x20x4 furnace filters for air quality and allergy sufferers?

SpiroPure 19x20x4 filters are available in MERV 8, MERV 11, and MERV 13. MERV 8 handles dust, pollen, and larger particles and suits most households. MERV 11 adds meaningful allergen reduction including finer dust, pet dander, and mold spores. It is an excellent upgrade choice for homes with pets or allergy sufferers. MERV 13 provides the finest standard residential filtration in our lineup and captures some smoke and particular matter including 50% of particles at 0.3–1 micron, but it is important to confirm your system supports the added airflow restriction before upgrading.

SpiroPure filters are USA-manufactured. These custom-cut filters are not returnable, so please double-check your measurements or contact our team before placing your order. Customer service is available seven days a week.

FAQs on 19x20x4 Air Filters

How do I measure for a 19x20x4 air filter?

Measure your existing filter's actual face dimensions (length and width) to the nearest 1/8". Those are the dimensions to order. If measuring the slot instead, subtract 1/4" from each face dimension. Depth is nominal: your 1" or 2" filter has an actual depth of 0.75" and 1.75", respectively. Deeper "whole-home" filters are cut up to 1/2" less than nominal depth per industry standard.
No. SpiroPure custom and non-standard filters are cut to order and cannot be returned once manufactured. Measure your existing filter or slot carefully before placing your order. If you're unsure of your dimensions, our customer service team is available seven days a week and can help confirm the right size.
Standard filter sizes use nominal dimensions. These are rounded numbers tied to common cabinet openings. Non-standard sizes like the 19x20x4 don't correspond to a standard nominal size, so actual face dimensions are listed to remove guesswork. Depth remains nominal: 4-inch nominal equals 3.5 actual, consistent with all pleated filters regardless of brand.
MERV 8 is appropriate for most homes because it captures dust, pollen, and larger particles without restricting airflow. If you've been using a flat fiberglass filter just to protect your system, MERV 8 is already a significant step up in filtration. MERV 11 adds allergen reduction for homes with pets or allergy sufferers. MERV 13 provides the finest residential filtration, but verify your system can handle the added airflow resistance before selecting.
1" and 2" deep filters typically last 2 to 3 months under normal residential conditions. 4" filters can last 6 months to a year. Homes with pets or heavy system runtime should replace filters more frequently. A visibly brown or gray filter or reduced airflow from vents are reliable replacement indicators. Use All Filters' free email reminders to stay on schedule.
SpiroPure 19x20x4 filters are USA-manufactured and priced well below OEM alternatives at the same MERV rating standards. Because this is a non-standard size, SpiroPure is often the most cost-effective option available. HVAC air filter packs and all orders over $99 ship free.
Yes. SpiroPure 19x20x4 filters are available in bulk multi-packs. When compared to buying one or two at a time from the store, buying in quantity online at AllFilters.com lowers the per-filter cost and ensures you have replacements on hand when the next change is due. Use All Filters' free email reminders so you always know when it's time.

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