# Filter King FKFA20X21A-6 20×21×1-Inch MERV 11 Air Filters, 6-Pack

Filter King FKFA20X21A-6 is a six-pack of MERV 11 pleated filters listed for air conditioners and furnaces. The nominal 20×21×1-inch size is not the stated actual thickness, so match the actual dimensions to your filter slot before ordering.

- [Original product page](https://best-deals.pro/product/filter-king-fkfa20x21a-6-merv-11-air-filters)
- [View offer](https://best-deals.pro/visit/filter-king-fkfa20x21a-6-merv-11-air-filters)
- Market: US
- Language: en-US
- Currency: USD
- Brand: Filter King
- Model: FKFA20X21A-6
- Category: Home & Kitchen > Appliance Parts & Accessories > Air & HVAC Filters
- Price: 67.98 USD
- Previous price: 90.72 USD
- Discount: 25%
- Price checked: 2026-11-14T06:40:48.622Z
- Rating: 4.2 / 5
- Reviews: 31

Prices and deal status are the latest recorded data, not a guarantee of availability. Confirm the price and availability with the store.

## At a glance

- The listing distinguishes a nominal 20×21×1-inch filter size from an actual size of 20 × 21 × .75 inches.
- The seller recommends replacing one-inch filters every 30 to 90 days. It says filters can last up to 90 days.
- Pleated construction and slide-in mounting are listed.

## Pros

- Six filters in one pack provide replacements for successive change intervals.
- The listing provides both nominal and actual dimensions, useful when checking fit.

## Specifications

### Identity
- Brand: Filter King
- Model: FKFA20X21A-6
### Dimensions and installation
- Dimensions listed: 21"L x 20"W x 0.75"Th
- Mounting type: Slide In
- Shape: Rectangular
### Materials and protection
- Material listed: Polypropylene
- MERV rating: 11
### Compatibility and quantity
- Compatible devices: Air Conditioner, Furnace
- Compatible HVAC systems: residential
- Quantity: 6

## Before you buy

- The listed dimensions show 0.75-inch thickness, while the title and description use a nominal 1-inch size. Measure the existing filter and confirm the slot accommodates the stated actual dimensions. The source recommends 30–90-day replacement intervals and claims up to 90 days, depending on use.

## In the box

- Air filters \(6\) (Included)

## A good fit for

- Households replacing a residential air-conditioner or furnace filter that matches the stated actual dimensions.
- Buyers seeking a MERV 11 pleated filter in a six-pack.

## Customer feedback

Aggregate ratings lean positive, with five-star ratings forming the largest share, but a notable one-star share shows that ratings are not uniformly favorable. Without customer comments, the reasons behind either positive or negative ratings are unknown. Treat the ratings as limited context, not evidence of specific filtration performance or fit. Confirm the actual dimensions for your system.

## Frequently asked questions

### What are the stated actual dimensions?
The listing gives 20 × 21 × .75 inches as the actual size, while presenting 20×21×1 inches as the nominal size. Check your existing filter and slot before ordering.
### How often does Filter King recommend replacing the filter?
The listing recommends changing one-inch filters every 30 to 90 days and says this filter can last up to 90 days. Actual replacement timing may depend on use.
### Which systems is this filter listed for?
The listing names air conditioners and furnaces and specifies residential HVAC systems.

## Alternative options

- [Filter King 21x21x1 Air Filter MERV 13, AC Furnace Filters \(12-Pack\) \| Dust & Allergy Control \(Actual Size: 20.5 x 20.5 x .75\)](https://best-deals.pro/visit/filter-king-fkfa20x21a-6-merv-11-air-filters)
- [Simply 24x24x1 Air Filter, Merv 11, 6 Pack, For Home AC Furnace & HVAC \(Actual Size: 23.75"x23.75"x0.75"\) DUST, Pet, & Allergy Control](https://best-deals.pro/visit/filter-king-fkfa20x21a-6-merv-11-air-filters)
- [Filterbuy 20x21.5x1 Air Filter MERV 8 Dust & Allergy Defense \(6-Pack\) \| Electrostatic Pleated HVAC AC Furnace Filters Replacement, Made in USA \(Actual Size: 19.88 x 21.50 x 0.75\)](https://best-deals.pro/visit/filter-king-fkfa20x21a-6-merv-11-air-filters)
- [Simply 16x25x4 Air Filter MERV 8, 6 Pack, For Home AC Furnace & HVAC \(Actual Size: 15.5"x24.5"x3.63"\) DUST Pet & Allergy Control](https://best-deals.pro/visit/simply-s-08-06-16254-16x25x4-merv-8-air-filter)
- [Filterbuy 20x25x5 Air Filter MERV 13 Smoke & Allergy Defense \(2-Pack\) \| Pleated HVAC AC Furnace Replacement for Trion Air Bear, Generalaire, Skuttle & More \(Actual Size: 19.63 x 24.13 x 4.88\)](https://best-deals.pro/visit/filter-king-fkfa20x21a-6-merv-11-air-filters)
- [360° Combi Replacement Filter for Dyson TP07, HP07, TP09, PC1 Air Purifier \| Fits H...](https://best-deals.pro/visit/filter-king-fkfa20x21a-6-merv-11-air-filters)
- [Aerostar 21 1/2 x 23 5/16 x 1 Air Filter MERV 11, Furnace Filter, 12 Pack \| AC & HVAC & Home, Air Conditioner & Heater Replacement, Actual Size \(21 1/2 x 23 5/16 x 3/4\), MPR 1200/FPR 7, Made in USA](https://best-deals.pro/visit/filter-king-fkfa20x21a-6-merv-11-air-filters)
- [ProShield 20x20x1 MERV 11 Enhanced Pleated HVAC Air Filter, 6 Pack \| Made in the USA High Performance Replacement Filter for Furnace & Air Conditioning Systems](https://best-deals.pro/visit/filter-king-fkfa20x21a-6-merv-11-air-filters)
- [Simply 12x18x1 Air Filter, Merv 13, 6 Pack, Furnace Air Filter for HVAC \(Actual Size: 11.75"x17.75"x0.75"\) DUST, Pet & Allergy Control](https://best-deals.pro/visit/filter-king-fkfa20x21a-6-merv-11-air-filters)
- [Aerostar 16 1/2 x 21 1/2 x 1 Air Filter MERV 13, AC Furnace Filter, 4 Pack \| HVAC & Home, Air Conditioner & Heater Replacement, Actual Size \(16 1/2 x 21 1/2 x 3/4\), MPR 1500/FPR 10, Made in USA](https://best-deals.pro/visit/filter-king-fkfa20x21a-6-merv-11-air-filters)
- [Aerostar Air Filter 21x21x1 MERV 11 AC Filter, HVAC, Furnace Filter, 6 Pack \| ACTUAL SIZE \(20.88 x 20.88 x 0.75\) AC Filter, Furnace Filter, Dust, Pet Dander, Smoke & Allergies MERV 11 \(MPR 1200\)](https://best-deals.pro/visit/filter-king-fkfa20x21a-6-merv-11-air-filters)
- [Aerostar 19 7/8 x 21 1/2 x 1 Air Filter MERV 13, AC Furnace Filter, 12 Pack \| HVAC & Home, Air Conditioner & Heater Replacement, Actual Size \(19 7/8 x 21 1/2 x 3/4\), MPR 1500/FPR 10, Made in USA](https://best-deals.pro/visit/filter-king-fkfa20x21a-6-merv-11-air-filters)

## Add-ons

- [Filter King 15.5x19.5x1 Air Filter MERV 8, AC Furnace Filters \(4-Pack\) \| Dust & Allergy Control \(Actual Size: 15.5 x 19.5 x .](https://best-deals.pro/visit/filter-king-fkfa20x21a-6-merv-11-air-filters)
- [Filter King 20x20x1 Air Filter MERV 8, AC Furnace Filters \(12-Pack\) \| Dust & Allergy Control \(Actual Size: 19.5 x 19.5 x .75\)](https://best-deals.pro/visit/filter-king-fkfa20x21a-6-merv-11-air-filters)

## Images

![Filter King FKFA20X21A-6 20×21×1-Inch MERV 11 Air Filters, 6-Pack — 1](https://best-deals.pro/i/glHSYS_FwmpkcmKVGKORolHJpB8jzZP6I3oNA0wuE6cTyYdtgZ5c6BLBhlyczYuqLbXYyHpGJpYSnZkB_sEVCzda2l1bvcCtq1yHL2C-wuNb4oCOhv5RvqmV.jpg)

![Filter King FKFA20X21A-6 20×21×1-Inch MERV 11 Air Filters, 6-Pack — 2](https://best-deals.pro/i/ldAsA9xhaTcpX2Qj1HD4pZHb1avXkKVSVd-2fteaf_iM4KgoWmRPV8FtuPTGzsPJdli4HtGrYeD8u5KTSSvTz0OLabf_BtGxqnHl2tCa6FNnuwJZQKXBHEk0.jpg)

![Filter King FKFA20X21A-6 20×21×1-Inch MERV 11 Air Filters, 6-Pack — 3](https://best-deals.pro/i/45noYpjpuxYQ8wr6_fIaO8M-V06UZVNT6yWCAgHhBzWh4Is-W1MR4Rg19R6P-4KB7eXI-AFCKwOp71R_ZaZbXFOkQ9wFKJX4hITdqSfGA6jIaQSfGizEBRQu.jpg)

![Filter King FKFA20X21A-6 20×21×1-Inch MERV 11 Air Filters, 6-Pack — 4](https://best-deals.pro/i/edyaaMEak5hrJTTpNdDBcO6_k4lU2iF4RA2QqPQfwI2FQUTtwCWw1eyVf9xD9G99wW-12emkBxcdaHEIVF0lYZIfHtFA5UKJIRzArQSdwCG31qJ529XkXp3L.jpg)