Heating and Cooling Indoor Air Quality

Should you get an expensive air filter?

There isn’t exactly a simple answer to this question. The short answer is “no” …well to a point. The absolute cheapest are probably a step or two below what you may want but the expensive ones aren’t necessarily what you want either. Let’s take a look at different aspects of air filters to get a better understanding of how things work.

So many acronyms: MPR, FPR, and MERV?

Let’s simplify this for you, MERV is the rating standard set by the American Society of Heating, Refrigerating, and Air conditioning Engineers. This is the rating to pay attention to. MPR is a rating system for 3M filters that were created by 3M and are only for 3M and similarly FPR is a rating by Home Depot for air filters sold in their stores. This is arguably just marketing, as opposed to MERV which is the long standing standard and the one that you should pay attention to. The MERV rating determines how much the filter is…well filtering.
So basically the lower the MERV rating, the lower the particulates you are filtering out of the system.

Do you have a lot of issues with allergies?

If your answer is no, then chances are the cheap ones are just fine for your needs. There is debate as to the actual effectiveness of the air filter removing allergens, but some can help to some degree.

The real job of the air filter is to keep the hvac system itself clean to prevent the build up of dust and debris inside of the unit.

There are better ways to remove allergens from your home, and if it’s a lot of allergies then you may want to call your hvac expert to learn more solutions to keeping the air in your home clean. Sometimes there can be other hidden issues causing the problem in the first place such as mold or air that is too dry. According to a paper released in 2014 the epa stated that “Filters with a MERV between 7 and 13 are likely to be nearly as effective as true HEPA filters”

Pleated vs Flat?

We’ve heard both sides of this one. Often the pleated are associated with the more expensive filters and for that matter associated with being too restrictive in terms of air flow. That said, there is also the counter argument that the pleating creates a larger surface area that actually creates more space for air to pass through to counter the better filtering.

Baking soda and Carbon filters

You will see a lot of different types of air filter and two that include additives that have become more common are activated carbon and baking soda. These are more specific use cases and are usually to help reduce and absorb smells carried in the air throughout the house. They aren’t usually necessary and are not a substitute for keeping your house clean. Just like reducing allergens there are better ways to remove odors from your home.

Possible problems with expensive filters

Some of these ‘good’ filters can cause problems for your system. By limiting the air flow to the unit the filter can actually put more stress on your hvac system. In really humid conditions this can even cause the evaporator coil to ice over in some systems. Some older air handlers may even have trouble performing at all if the filter is too restrictive.

Higher utility bills

There is also the chance that the more expensive air filter with the higher MERV rating is going to cost more. Your unit will have to work harder to pull air through a filter that allows less air flow.

Middle of the road

Some people prefer to not go with the absolute cheapest, flat spun fiberglass filters as the consensus is that these just aren’t as good as a basic pleated filter. While they usually do allow good air flow you may want to go a step or two up from the cheapest but not bother with the ultra premium HEPA filters.

Just look at it

Many furnaces have a label that will tell you the recommended MERV rating for it’s own optimal performace. Since there are a lot of different hvac system designs there isn’t exactly a one size fits all air filter. Consider your own needs as to whether or not you think you need extras like carbon or baking soda.  A lower MERV is likely better for your system, but it’s pretty much best to go with the rating and filter thickness your system was designed for.  If you are in doubt, give us a call and we can help!