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Your heating, ventilation, and air conditioning system heats, cools, and distributes air throughout the living space. It also contributes to keeping the indoor air clean and fresh. The filters in ducted HVAC systems are usually located inside the return air duct before the entrance to the duct system. An HVAC system draws pollutants circulating in the air throughout homes and offices into the return air duct to capture airborne pollutants and keep them from entering the duct system and the living space.
Standard HVAC filters generally capture large particulates, such as dust, pollen, animal dander, and hair. They are designed to protect the components of the heating and cooling system. Small particulates, such as bacteria, tobacco smoke, and gases, pass through standard filters, enter your living space, and can be inhaled into your respiratory system. To put the size of particulates in perspective, a micron is 1/25400-inch. Particles of 40 microns or more are visible to the naked eye.
If you are concerned about the air quality in your home or office, upgrading the filters on your HVAC system can improve the air you breathe indoors. The staff at Atticman Heating and Air Conditioning, Insulation can help you select a filter that will work with your heating and cooling system. We serve residential customers in Sacramento, CA, and nearby communities.
Why Particulate Size Matters
Airborne particulates come in many sizes and shapes and are made of several substances, such as bacteria, viruses, gases, pollen, and silt. What is commonly called household dust comprises many materials, including bits of pollen, hair, pet dander, mold, liquid droplets, and bacteria.
When we inhale, we draw in air and any particulates in the air. According to the Environmental Protection Agency, particles smaller than 10 microns can travel through your respiratory system to the lungs. The smaller the particulates, the further they can be drawn into the respiratory system. Some end up in the deepest part of the lungs, where they mix with oxygen, enter the bloodstream, and circulate throughout the body.
Although many particulates are benign, some have health risks. Particles smaller than 2.5 microns pose the greatest risks because they have the best chance of reaching the deepest part of the lungs and entering the bloodstream.
Common Household Pollutants and Their Particulate Size
Many common household pollutants trigger asthma and allergies. Some can cause health problems depending on the amount and frequency of exposure to the substance.
Common household pollutants include:
- Antiperspirant and deodorant aerosol sprays at 6 to 10 microns
- Bacteria at 0.3 to 60 microns
- Dust mites at 100 to 300 microns
- Household dust at 0.5 to 100 microns
- Mold spores at 3 to 40 microns
- Pesticides at 0.001 micron
- Pet dander at 2.5 to 10 microns
- Pollen at 10 to 1000 microns
- Smoldering cooking oil at 0.03 to 0.9 micron
- Tobacco smoke at 0.01 to 4 microns
- Viruses at 0.005 to 0.3 micron
Types of Filters
Filters vary in size, efficiency, type, rating, and thickness. Many HVAC manufacturers offer high-efficiency filtration systems that integrate with their systems. You can also purchase stand-alone filters that offer the quality of filtration you need. In general, thicker filters are more effective at capturing particulates. However, thicker filters also restrict airflow. Your HVAC contractor can help you select a filter that works with your heating and cooling system and provides the protection you need.
Flat-Panel Fiberglass Filters
Flat-panel fiberglass or spun glass filters are the least effective at trapping airborne pollutants, capturing approximately 10% of the pollutants that enter the system. They trap large particulates, such as hair, textile fibers, and some pollen. They are the least expensive of all the filter types, are disposable, and will not significantly restrict airflow. They are not recommended for those with allergies or other respiratory problems.
HEPA Filters
High-efficiency particulate air filters (HEPA filters) capture approximately 99.7% of airborne pollutants as small as a third of a micron. However, they are thick, which impedes airflow. Although some HVAC systems cannot accommodate HEPA filters, several manufacturers offer whole-home HEPA filtration systems that work with their equipment. The technicians at Atticman Heating and Air Conditioning, Insulation service all brands of HVAC equipment and can recommend filters that will work with your system.
Electrostatic Filters
Electrostatic filters, made of paper, cotton, or polypropylene, use an electrostatic field that functions like a magnet to attract pollutants. They can capture small particulates, including viruses and bacteria, without affecting airflow. They are available in either reusable, washable, or disposable filters. Although washable filters cost more, they last for years when properly maintained.
Pleated Filters
Pleated filters are made of fiberglass, polyester, or plastic. Pleats add surface area, which increases the filter’s ability to trap pollutants. Depending on the rating, pleated filters capture 20% to 50% of pollutants, such as pollen, mold, and household dust. Those with higher ratings are more efficient but are thicker, which can impede airflow. They cost more and should be changed every three to six months.
MERV Ratings and What They Mean
Filters are rated according to their efficiency at trapping particulates. The American Society of Heating, Refrigerating, and Air Conditioning Engineers developed the Minimum Efficiency Reporting Value (MERV) to measure and compare a filter’s ability to capture particulates between .03 and 10 microns. The scale ranges from MERV 1 to MERV 16. The higher the MERV value, the better the filtration.
Experts recommend using filters rated MERV 8 and higher for household use, selecting the highest value that will work with your HVAC system. Filters rated MERV 13 and above are used in laboratories, hospitals, and clean rooms. For people suffering from allergies, asthma, and other respiratory issues, select filters between MERV 11 and MERV 13.
Higher MERV ratings can make an HVAC system work too hard to push air through the filter, damaging the equipment and affecting comfort.
Maintaining Your Filter
Keeping your filter clean is the key to performance. Dirty filters impede airflow, make the system work harder to produce conditioned air, and are one of the primary reasons that HVAC systems stop working. Usually, filters should be cleaned or replaced every three to six months. If you have pets or live in an area with poor air quality, you may have to clean the filter more often.
Founded in 2015, Atticman Heating and Air Conditioning, Insulation is a full-service HVAC company offering new installations, repairs, and maintenance of heat pumps, ducted heating and air conditioning systems, ductless mini-splits, furnaces, radiant heating systems, and more. We also install and maintain water heaters, ductwork, and whole-house fans. Our electrification services help you shift from equipment powered by fossil fuels to all-electric systems, focusing on clean power and energy efficiency. Our maintenance plans help keep your heating and cooling equipment functioning efficiently and dependably.
We also offer insulation services. Well-insulated homes use less energy for heating and cooling, which can extend the service life of your HVAC system and reduce utility bills.
If you notice odors or other signs of poor indoor air quality, call Atticman Heating and Air Conditioning, Insulation for a consultation. We can help you select a filter that works with your heating and cooling system and maintains good indoor air quality.
