Surprisingly many people think so. There more to the filter you use in your furnace or air handler that effects your indoor air quality as well as your wallet.
If your using a spun fiberglass filter that you can see through, your wasting your money. This type of filter only captures the large particles it doesn't capture the smaller particles. So what good is it really doing for the air you breathe. Honestly not much.
A filter needs to trap as much as possible to improve the air you breathe. If you have allergies, asthma, or other breathing problems this is essential to your quality of life. A cheaper filter allows the smaller particles to pass through the filter and to enter the furnace reaching the evaporator coil, the airstream, and the air you breathe. Eventually the coil can become clogged with those particles reducing air flow and providing a surface for mold to grow and thrive. Who wants to breathe that?
If that isn't enough, what about the cost to you for maintenance? A dirty coil reduces air flow, makes the evaporator fan work harder, and it makes out to your condenser by raising your line pressure and working your compressor harder. This all cost you more in operating cost. Not to mention the cost of removing the evaporator coil and cleaning it. This can cost anywhere from $375.00 - $550.00. Who can afford that these days?
This isn't to say the filter you use will prevent you from ever having to clean your coil. It will certainly help you prevent any of these problems and improve the air you breathe. You don't have to spend a small fortune on a filter or filters to improve the air you breathe. There are many filter choices out there. You just have to make a wise choice as to what your needs are and what filter best serves you.
A couple of filter choices available are polyester foam filters and extended surface pleated filters.
The polyester foam panel filter is a good choice they are inexpensive and do a a better job of stopping and collecting pollutants than a fiberglass filter. They are available in a bulk roll, cut to size, with or without a tackifier and in a traditional cardboard frame.
A better choice is the extended surface surface pleated filters. They are designed with less resistance to air flow than panel filters. Their design also extends service life and reduces maintenance cost. Many are electrostatic and bacteria resistant.
The best choice is a filter thicker than the standard 1" filter. The problem with these filters your average air conditioning system isn't set up for these filters. They have been used almost exclusively in commercial systems. What has been available for residential systems require a field installed filter housing. Which can be costly to install or integrate into many applications. The advantage to these filters is longer service life (one filter last 6 to 12 months), low pressure drop, greater surface capacity to capture more particles, and electrostatic and bacteria resistant.
Fortunately, many manufacturers are seeing the advantage of these filters in the residential market. You can now get a 5" pleated filter designed to fit your existing return air grille. These filters go one step farther by adding a foam a foam gasket to prevent air by-pass so you get maximum air filtration through your filter.
I hope this article informed you on the different types of filters available to you and helps your choice of filter easier.