Discover our premium selection of 21x21x4.5 air filters, designed to enhance your indoor air quality and create a healthier living environment. These filters are engineered to capture a wide range of airborne particles, including dust, pollen, pet dander, and smoke, ensuring cleaner air for you and your family. With various MERV ratings available, you can choose the perfect filter to meet your specific needs while prolonging the lifespan of your HVAC system.
21x21x4.5 Air Filter
Keep your indoor air fresh and clean with our efficient 21x21x4.5 air filters designed for superior performance
Product List
20x21x1 MERV 11 Filters - 4 Pack
Filter King
Product Review Score
4.65 out of 5 stars
146 reviews$64.89
21x24.5 MERV 8 Filters 4-Pack
Filter King
Product Review Score
4.44 out of 5 stars
125 reviews$58.76
MERV 11 Pleated Air Filters 2-Pack
Filterbuy
Product Review Score
4.76 out of 5 stars
187 reviews$38.98
21x21x4 MERV 11 Filters (2-Pack)
Filterbuy
Product Review Score
4.93 out of 5 stars
216 reviews$66.33
MERV 11 Air Filter 6-Pack
Filterbuy
Product Review Score
4.93 out of 5 stars
93 reviews$82.08 $77.98
21x21 MERV 11 Air Filters (2-Pack)
Filterbuy
Product Review Score
4.23 out of 5 stars
156 reviews$33.98
21x21x1 MERV 8 Air Filters 2-Pack
Filter King
Product Review Score
4.59 out of 5 stars
12 reviews$29.72
Our 21x21x4.5 air filters are designed to enhance indoor air quality by effectively capturing a wide range of airborne particles, including dust, pollen, pet dander, and mold spores. Built with high-efficiency filtration technology, these filters help to ensure that your HVAC system runs smoothly while reducing allergens in your home. By regularly replacing your air filters, you can improve the overall efficiency of your heating and cooling systems, prolonging their lifespan and saving on energy costs.
Available in various MERV ratings, our 21x21x4.5 filters provide an array of options to meet your specific air purification needs. Whether you are seeking a basic filter for routine maintenance or a high-performance option for allergy relief, we have you covered. Browse our selection to find the perfect fit for your home or office and breathe easier knowing you’re investing in superior air quality.