We use a gas fireplace as a supplement to our heat pump during the winter months and we have a cat. The filter keeps the coils on the indoor unit cleaner than another filter we have used in the past.

the physical dimensions are > 4", actually close to about 4.5". Be sure you're housing will accommodate 4.5" before purchasing. Can't comment on the function because these would not fit.

I have used these filters since I've owned my home for 4 years. You can definitely tell they work! Barely any dust around my house and when I go to change it every 3 months it's definitely dirty!

[This review was collected as part of a promotion.] I've been using these filters for several yrs and they are great. I originally bought them because my son has asthma.

According to our service technician, pet hair can wreck havoc on your HVAC system. The Healthy Living Air Filter addresses the issue so that it is no longer a problem. Works great!

I love buying this product. It does everything it says it will. The air in my home is always fresh and clean. And no dust particles floating around. It is an excellent choice.

I have used the Filtrete air filters for many years. They have definitely helped with allergies in our home. I can actually tell from how fresh the air is when it is time to replace.

Even if you don't run or have a whole house fan unit buying the 12x12 is a great way to a cheap air filter. Just tape a 12x12 Filtrete onto the back of a box fan and you're good to go!

I need a 18x20x1 1900 filter but Filtrete doesn't make one, settled for a 1500 but not satisfied. Found an Aerostar filter and an evaluating it, but would prefer Filterate for good quality control and honest rating assessment.

These filters are difficult to fine in stores because of their size. The cost is way more than other size filters, and I fail to see why because they are basically paper and a wire mesh construction.