Your heating and air conditioning system pulls in air over coils to change the temperature and then blows them through ducts to other rooms. Your air filter is typically placed where the air is brought into the system. It is used to trap particles that get sucked in to keep them from clogging coils or blocking the blower. These particles are typically things like dust, pollen, pet dander, bacteria, and spores.
What Type of HVAC Filters Should I Use?
There are many different types of air filters, and various ratings are used to rate them. The Minimum Efficiency Reporting Value (MERV) is a scale from 1 (weaker filters) to 16 (stronger filters). MERV was established by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE).
The Federal Trade Commission and the Environmental Protection Agency recognize the Clean Air Delivery Rate (CADR) method used to measure air purifier efficiency. While some high-end filters can be up to 1200 CADR, most are between 12 CADR and 240 CADR. Some brands also have their own rating systems.
- Flat-panel filters are the most traditional and affordable, and they have fibers (generally fiberglass) stretched over a framework. They’re disposable and easily replaced.
- Pleated filters are a disposable type of filter that use screens of dense cotton or plastic fibers, and as the name suggests, they have pleats. The pleats cover more surface area, allowing the filter to catch more debris.
- Electrostatic filters carry a charge to help capture even smaller particles like pollen, smoke, or bacteria in their screens. They can be either flat or pleated and disposable or washable.
- Washable or reusable filters come in both pleated and flat-paneled options. This type of filter can be hosed down with water or vacuumed to remove the buildup of particles.
- High-Efficiency Particulate Air (HEPA) filters are commonly used in hospitals, labs, or homes of people with allergies or compromised immune systems. HEPA filters consistently remove 99.97% of particles from the air. Consult with your HVAC professional before switching to HEPA filters. Not all commercial HVAC systems are designed to use these extra-strong filters.
How Often Should HVAC Filters Be Changed?
A general rule of thumb is about every one to three months after you installed it. A key sign you should change your filter is a buildup of ashy-looking gray dust on the duct side of the filter. Some experts argue that more dust on the filter technically makes it “better” at filtering other particles, but this is at the expense of your unit’s efficiency.
Do HVAC Filters Help with Covid?
In a building or small space, HVAC filters can reduce contaminants in the air, including viruses. However, the EPA notes that “By itself, air cleaning or filtration is not enough to protect people from COVID-19.” Good air ventilation and filtration can be a part of reducing the threat of airborne transmissions indoors when used along with other best practices like mask wearing and social distancing.
Do HVAC Filters Make a Difference?
In addition to improving air quality by removing dust and bacteria, keeping up with cleaning or replacing your air filter can help maintain and extend the life of your AC unit. Better air filtration can also decrease the frequency of cleaning air ducts.
Can You Put an HVAC Filter in Backwards?
Yes, you can install an HVAC filter backward. Though your filter may look similar on either side, the truth is that one side is more porous than the other to allow particles into them. If you do put your AC filter in backward, air will have a more difficult time flowing through it, and your unit will have to work harder to circulate air.
Call Henick-Lane for All of Your Indoor Air Quality Needs
At Henick-Lane, we are experts in all aspects of commercial HVAC, including indoor air quality. We have more than half a century of experience serving the New York City area’s high-rises, commercial buildings, and facilities. Contact us online to request a consultation or call (718) 768-7277 to arrange an indoor air quality assessment. We look forward to hearing from you.