One of the most common questions I get from home owners is how often to change the air filters and what is the best filters to use.
There is no universally correct answer to this question. A few varying factors determine what a good answer is. One thing is for sure: The better the quality of the filter, the more it will protect your evaporator coil from getting plugged. A Proper evaporator coil clean can cost anywhere from $400 to $800 but that is another subject of it’s own.
The MERV rating on the filter will tell you which are the best filters available and manufacturers should have that rating on the filter usually next to the size and expressed in “M#” for example if it is a MERV 8 it will show “M8”.
A good quality pleated filter will typically have a MERV rating of 7 or 8 which is pretty good quality and by and large is what we recommend for the majority of applications. However if you would like to use an even higher MERV filter we highly recommend to use the thick filters such as 4 inch or more which will typically require modification to your return duct. The reason is that very high quality material will clog faster because it traps more particles, thus the need to make these filers in the form of thicker pleated design providing extra surface area.
The typical cheap filters that are not pleated usually have a MERV rating of 4 which is okay but not very good, yes those filters are cheap but they offer little protection for your evaporator coil and indoor quality. You can find decent non-pleated MERV 5 filters at a good price too if buying MERV 7 or 8 pleated filters is out of your budget. A basic rule of thumb is ; the more you can see through it the lesser quality it is.
So how often should you change your filter? Well, every home is different. Factors such as inside pets, smoking, number of people in the home, dusty homes and blower motor run time are all to be considered. When you can see a thin layer of dust or dirt and the filter has completely changed color it is time to replace it. In most cases this is about 1-2 months assuming you got the MERV8 1 inch pleated filter that we recommend. For MERV 4 filters you can check them every 2-4 months. The time intervals tend to change with the seasons as well.
We hope you found this article helpful.