How HVAC Filters Affect System Performance and Longevity
The air filter is one of the most important components in your heating and cooling system.
In the Pacific Northwest, where we deal with everything from heavy pollen to wildfire smoke, air filters safeguard your health, utility bills, and HVAC system.
Let Carrier Northwest help you find a trusted Carrier dealer who understands how your local climate impacts your indoor environment. Our online directory makes it easy to connect with HVAC experts in Oregon, Washington, and Montana. Your local Carrier dealer knows how to improve indoor air quality (IAQ) and can match the best air filter to your HVAC system.
In the meantime, let’s dive into the world of HVAC filters and discover what they do, what types there are, and why replacing dirty filters matters.
What Does Your Air Filter Actually Do?
The standard air filter’s job is to protect your HVAC system, primarily the blower motor and the evaporator coil.
While it is operating, your HVAC system draws indoor air through your return vents, passes it through the filter, and then moves it over the heating or cooling elements. The filter traps airborne particles, including dust and dust mites, pet dander and fur, mold spores, pollen, dirt and microscopic debris.
Without a filter to shield your system, those microscopic particles would coat your sensitive indoor coils, making it difficult for them to absorb or release heat.
Dust would settle in your fan motor, causing it to overheat and burn out. It would build up inside your air ducts, clog the gas ports on your burners, and coat your heat exchanger. Dust mites mixed with moisture could form sludge in your condensate pan and drain line.
How Air Filters Affect Your System
Your choice of filter and how well you maintain it directly dictates your system’s performance.
Air Filters and System Efficiency
When dust, pet hair, and debris coat an air filter, they can block air circulation. Your furnace or heat pump has to draw more electrical power to overcome the blockage. When your system uses more energy, you pay higher utility bills. A clean filter provides the airflow your system needs to work efficiently.
HVAC Airflow and Filters
Restricted airflow is the top cause of premature HVAC breakdowns. When air can’t move freely through your HVAC system, it can develop issues.
- Your furnace overheats and trips the safety limit switch, which shuts it down. Every time it turns back on and heats, the switch triggers.
- Continuous overheating can stress and crack the furnace heat exchanger.
- Your heat pump or air conditioner struggles to absorb heat, causing the indoor coil temperature to drop. Condensation on the coil can freeze, which can damage the compressor if the system continues to run.
- The blower motor overheats and burns out.
Air Filters and Equipment Lifespan
Regular maintenance and clean HVAC filters extend your system’s lifespan. Neglect leads to premature failure.
HVAC Filter Types
Filters are not all created equal. They vary in thickness, construction, material content, and efficiency.
Fiberglass filters are made of fine spun glass fibers. The filters are inexpensive, thin, and flat. They trap larger particles of lint and dust, which protects your HVAC system but not your indoor air quality (IAQ).
Pleated air filters made of synthetic material or cotton have more surface area than flat filters. They catch more debris and much smaller particles, including pet dander and pollen.
High-efficiency media filters are made of polyester-cotton blends or other synthetic fibers. They are approximately four to five inches thick and installed in a media cabinet that sits between the furnace and the return air duct. They can trap microscopic particles, dust, bacteria, allergens, and smoke.
Air Filters and MERV Ratings
Every filter has a Minimum Efficiency Reporting Value (MERV) rating. MERV is a scale from one to 20 that rates how effectively a filter traps particles ranging from 0.3 to 10 microns.
MERV 1-4: These are basic fiberglass or polyester flat filters. They capture particles that are 10 microns or larger, such as lint or dust.
MERV 5-8: These standard pleated filters catch particles, such as dust, pollen, and mold spores that are 3.0 to 10 microns in size.
MERV 9-12: They are considered high-efficiency and are great for households with pets, allergies, or asthma because they capture particles as small as 0.30 microns.
MERV 13-16: This is hospital-grade filtration. Some residential systems can’t handle the airflow restriction these filters cause. Ask your local Carrier dealer whether a MERV 13-16 rating is best for your heating and cooling equipment.
The U.S. Environmental Protection Agency (EPA) recommends at least a MERV 13 rating, or the highest rating your system can handle, if you decide to upgrade to a higher-efficiency filter.
Replacing Your HVAC Filter
How often to change your HVAC filter? It depends on your household, the type of filter used, and what your HVAC system’s manufacturer recommends.
Inspect basic, one-inch filters for dirt and clogs every month, especially when your HVAC system is in heavy use. Read your manufacturer’s recommendations for filters and replacement frequency.
A general rule for replacement is to swap out standard, one-inch filters every 30 days if your household includes pets or family members with allergies. If you have no pets or non-shedding ones, replace filters in 60 to 90 days.
The thick media filters often last six months to one year. Inspect them at six months or sooner during heavy use in the summer and the winter.
Find a Local Carrier Dealer Today!
If your system is due for a tune-up or you need professional guidance on upgrading your HVAC air filter, browse our Carrier Northwest online directory to find a trusted Carrier dealer in Oregon, Washington, or Montana. Click the link to get started.