Air filters may be one of the most neglected, often forgotten components in residential HVAC systems here in Charleston.
It’s easy to overlook air filters as they quietly do their job unseen in most cases.
Despite this understandable overlooking though, air filters play a vital role in both indoor air quality and overall HVAC system performance.
The EPA lists indoor air quality as one of its top environmental health risks, so understanding the relationship between your HVAC system’s air filter and your home’s air quality shouldn’t be overstated.
We’ll get into more detail below about air filter ratings & types, but since most of the air in our homes here in the Lowcountry pass through your air conditioning or heating system, the air filters you choose can ultimately decide how good (or bad) your home’s air quality is.
We’ve stated the role air filters play in system efficiency & lifespan in several blog posts over the years, so we’ll be brief here.
If your air filters are clogged with dust & debris, this will result in buildup in your ductwork and sometimes even back to the main unit itself. This clogging means your system has to work harder to push air through it, resulting in overworking. This overworking will drive up your energy bills and ultimately can shorten the lifespan of your system.
To help end users of air filters, the American Society of Heating, Refrigeration and Air-Conditioning Engineers (ASHRAE) created the Minimum Efficiency Reporting Value or MERV rating. The MERV rating essentially allows users to see how effective air filters are at capturing particles that pass into it.
MERV ratings range from 1 (lowest effectiveness) to 20 (highest) which take into account three main characteristics:
To get a better sense of the rating system, let’s look at some of the more common air filter types and their associated MERV ratings.
(1 to 4 typical MERV rating)
Pros: Inexpensive, good for protecting HVAC components (less air flow resistance)
Cons: Not great at cleaning air
(5 to 13 typical MERV Rating, up to 16 for high efficiency types)
Pros: Pleated material increases filter efficiency lowered air resistance for HVAC system
Cons: Less efficent than HEPA for the smallest particles
(17 to 20 typical)
Pros: Top of the charts as far as filtering all types of particles
Cons: Most are too large for residential systems, restrict air flow which could result in overworking your HVAC system
(1 to 4 typical)
Pros: Longer lifespan of filter use, durability
Cons: Requires frequent cleaning & needs time to dry to prevent germ/mold buildup, more expensive, not great at cleaning air
As with choosing the best HVAC system for your home in Charleston, selecting the best air filter can be a challenge. There are tradeoffs between optimal air filtration, which gives you better air quality and optimal system performance, which keeps your electric bills down and extends your systems lifetime.
Our best bet for a good balance between these two would be the pleated air filter types. However, if you favor better air quality or better system performance, you can choose the air filter type on either end of spectrum to get the results you want.