One of the most common questions our HVAC techs get from clients is, “What is the best filter for my system?” Filter choice can be very important to both the quality of your home’s air quality and your HVAC’s system ability to run efficiently, but for many people the number of filters available can lead to confusion about what will work best for their home environment.
When considering what filter is right for your home, a few questions need to be asked:
- Do you have pets?
- Are you currently experiencing issues with dust?
- Does anyone in your home suffer from allergies or a compromised immune system?
- Is there a smoker in your home?
If you answered “yes” to any of the above questions, then you will want to pay special attention to something called the minimum efficiency reporting value (MERV) scale. This scale has a rating system from 1-20, with 20 being the highest value, which measures the ability of a filter to remove particles from the air, the ability to resist airflow, and the life expectancy of the filter. If you suffer from breathing problems, or have a high number of possible pollutants in your home (such as tobacco smoke or pet dander), then you’ll likely need a filter with a higher MERV rating.
Basic Fiberglass Filter
Pros: Extremely cheap
Cons: Does nothing to improve air quality
Fiberglass filters are the most basic air filters available for HVAC systems, and their price reflects that. Most standard size fiberglass filters can be purchased for only a couple of dollars. These filters are disposable, have a short lifespan, and usually have a MERV rating between 1-4. If you don’t suffer from any sort of respiratory issue, and don’t notice a lot of problems with dust in your home, this might be a good option for you.
Pros: Relatively inexpensive, removes more particles from the air
Cons: Need to be replaced on a regular basis, as clogging can reduce airflow
Pleated filters generally have a MERV rating somewhere between 5-13, and do a much better job than basic fiberglass filters at removing particulate matter from the air. These filters are a good choice for those who don’t have major problems with respiratory issues, but still require a higher-powered filter. It’s very important that these filters be checked and replaced on a regular basis, as their ability to gather a larger amount of particulate matter also means that they can become clogged faster than basic filters.
Pros: No replacement needed
Cons: Expensive, require extra maintenance, can invite mold growth
Electrostatic filters are washable filters made with electrically charged materials that attract particulate matter to cling to the filter. While the idea of a washable filter may seem great, these filters can cause some problems, the biggest one being the encouragement of mildew and mold to grow on the filter itself. They also take a good deal of time to clean properly. MERV ratings generally range between 8-12, meaning that they do provide removal of a good deal of particulate matter, but overall they may not be a great option thanks to their extra maintenance requirements.
Pros: Remove the most particulate matter from the air
Cons: Expensive, May require retrofitting, Could restrict airflow
HEPA filters are a great option for households including someone who suffers from asthma, allergies, or compromised immune systems, as they have MERV ratings between 17-20. These are the air filters used in hospitals, and they remove 99% of particulate matter from the air, which will definitely improve your home’s air quality. In order to remove that much particulate matter, however, the filter is between 4-5 inches wide and is made from tightly woven material that can restrict airflow. Some HVAC systems aren’t able to operate properly with this type of filter, so a professional may need to come assess your system to see if retrofitting is possible.
Still wondering what filter is right for you? Give us a call at (205) 564-5004 and we’ll help you out!