Customer reviews from Filterbuy
Filterbuy - 21x21x4 MERV 13 Smoke & Allergy Defense, Electrostatic Pleated HVAC AC Furnace Air Filters Replacement (4-Pack) - Blue
Average customer rating
4.1
(1,155 Reviews)
Rating breakdown 1,155 reviews
5 Stars
716
4 Stars
109
3 Stars
127
2 Stars
88
1 Star
115
Customer Reviews for Filterbuy - 21x21x4 MERV 13 Smoke & Allergy Defense, Electrostatic Pleated HVAC AC Furnace Air Filters Replacement (4-Pack) - Blue
Customer Rating
4
I dislike the blue colored filters
on March 29, 2026
Posted by: Customer
The filters work fine. But I would rather have white filters so I can more easily see the amount of dirt on them. The blue filters make this difficult.
Written by a customer while visiting Filterbuy
Customer Rating
5
Filter
on March 28, 2026
Posted by: Customer
This is what our furnace requires and they work great
Written by a customer while visiting Filterbuy
Customer Rating
5
Wrong Filter right size
on March 26, 2026
Posted by: Customer
I ordered a 14x20x4 I needed a 14x20x4 Return Air Filter not a furnace filter. I did not know the difference. I need to return these four filters
Written by a customer while visiting Filterbuy
Customer Rating
5
Easy to install and since
on March 20, 2026
Posted by: Anonymous
Easy to install and since we have cats, do a great job plus they still look pretty good even after three months.
Written by a customer while visiting Filterbuy
Customer Rating
4
4" filter review
on March 15, 2026
Posted by: Anonymous
So far they seem to be performing well! However the pleats should be evenly spaced and the ones that I received are uneven and tight together creating areas with less air flow!
Written by a customer while visiting Filterbuy
Customer Rating
5
What A Savings
on March 12, 2026
Posted by: Anonymous
The price is outta sight! I will not find out if the filters are worth it for another 3 months
Written by a customer while visiting Filterbuy
Customer Rating
1
Filters
on March 10, 2026
Posted by: Anonymous
Please stop sending me filters please I didn't sigh up for all these filters, I have enough. PLEASE DON'T SEND ANY MORE FILTERS, I ONLY USE 2 FILTERTS PER YEAR.CORDELL KENNEDY
Written by a customer while visiting Filterbuy
Customer Rating
3
Size is not appropriate
on March 5, 2026
Posted by: Anonymous
Ordered 20x25x4 for aprilair system and the size of filter is off by 2inches. It would be better if filter buy has a exact measurements
Written by a customer while visiting Filterbuy