Call Us TodayHow Is Air Purified?
Every home has a variety of sources of indoor air pollution that can make the air inside several times more polluted than the air outside. This includes the building materials your home was made with as well as your furniture, cleaning products and cooking appliances. If you live in an urban area where the outdoor air is also fairly polluted, your indoor air quality may be worse due to outdoor pollution getting inside. Virtually all homes could greatly benefit from upgrading their air filtration or installing an air purification system. We’ll look at the importance of having adequate air filtration or purification as well as the differences in how each process works.
How Your HVAC Filters the Air in Your Home
All HVAC systems have one or more filters that provide at least some level of whole-home air filtration. In a central HVAC system, the air filter is located in the return side of the home’s ductwork, where air gets drawn into the system. Most systems have a single air filter that slides into the return plenum, the large sheet metal compartment that attaches to the furnace and/or air handler. This type of filter is typically referred to as a furnace filter or air handler filter.
Some central HVAC systems instead have multiple return vent filters. As the name suggests, this type of filter is located just behind the grille or cover of each of the home’s return vents. Don’t ever try to run your HVAC with both a furnace/air handler filter and return air filters. The reason is that you’ll end up with greatly restricted airflow that decreases the system’s performance and may lead to it frequently overheating or the AC evaporator coil often freezing up.
Although many people believe that the purpose of these HVAC air filters is to improve indoor air quality, this really isn’t the case. Standard HVAC air filters with a higher efficiency rating help with indoor air quality by filtering out some allergens and pollutants. Nonetheless, the main purpose of standard 1-inch HVAC air filters is to trap dust so that it doesn’t get into the furnace and air handler and cause damage or lead to a drop in efficiency. To improve your home’s indoor air quality, consider upgrading to a whole-home air filtration or purification system.
How Whole-Home Air Filtration Works
Air filtration uses a physical barrier that traps particles suspended in the air as it passes through the filter. A high-quality 4- or 5-inch media filter or air cleaner is extremely effective at filtering out particles like pollen, mold spores, pet dander, dust mites and at least some smoke particles and combustion fumes. However, media filters have little to no effect on chemical vapors and other similar types of airborne pollution.
Media filters are designed to be used instead of a standard 1-inch air filter and are mounted with the return air plenum. That means you’ll need to have your ductwork altered to accommodate the filter. Most media filters are rated MERV 14 to 16, which means they provide the highest level of filtration available outside of a HEPA filter. However, you need to check with an HVAC expert before purchasing one because filters rated this high are usually meant for commercial or industrial buildings.
For residential HVAC systems that use a 1-inch filter, you usually can’t use anything higher than MERV 12. If you do, you’ll end up with the filter restricting the airflow so much that it would have almost the same effect as never replacing the filter. This generally isn’t an issue with a media filter despite it working so efficiently. The reason is that the filter is large enough that the pleated filter media is spread out further so air can easily flow through without being restricted.
The Difference Between Whole-Home Air Filtration and Air Purification
While many people use the terms air filtration and air purification interchangeably, they aren’t the same thing. Most whole-home air purification systems have a high-efficiency pleated filter that provides the same level of filtration as a media filter or air cleaner. However, they also use one or more other methods to ensure that the air flowing through them is fully cleaned and purified. For instance, many systems have UV lights that are effective at destroying around 90% of fungal spores, bacteria and viruses. There are also standalone germicidal UV light systems that you can add to your HVAC system to serve the same purpose.
Some of the most effective whole-home air purification systems also use a process known as photocatalytic oxidation. In this type of system, the UV lights serve two different purposes. The first is to destroy bacteria, viruses and mold. The other is to shine the UV rays onto special photocatalytic plates that are usually made of titanium dioxide or some other reactive metal alloy.
When the catalyst is exposed to ultraviolet radiation, it reacts with water molecules in the air to produce hydroxide ions known as hydroxyl radicals. These ions are highly reactive and attract most of the remaining gaseous chemicals and odor-producing molecules, such as those from pets, cleaning products, and cooking. When the ions come into contact with the chemicals, most of them either get destroyed or change into less harmful chemicals. This process allows the purification system to reduce the amount of volatile organic compounds (VOCs) and other chemicals so that the air flowing out of the purifier is much cleaner and smells much better.
Another important thing to note about photocatalytic oxidation is that the hydroxide ions also flow out into the ductwork and circulate throughout the house. That means the purifier doesn’t just clean the air flowing through your HVAC system but actively works to purify the air throughout your entire house. It eliminates bacteria, germs and chemicals on all your home’s surfaces.
The only issue with some systems that use photocatalytic oxidation to purify the air is that they can end up contributing to more air quality issues than they solve. This is because some of them produce ozone and other harmful byproducts. Having a purifier that produces ozone is a major concern since it is a known irritant and can especially create issues for people with asthma and other respiratory ailments. That’s why, when deciding which type of whole-home air purification system to install in your house, you need to look for a system that has been proven not to produce ozone.
Hoff Heating & AC is a family-owned company that has been serving residents in O’Fallon and the St. Louis area since 1983. In that time, we’ve established a reputation as one of the area’s most reliable and trustworthy HVAC and indoor air quality contractors. If you’re looking for ways to improve the air in your home, we offer a wide range of air filtration and purification options to meet all your specific needs.
For more information on our indoor air quality services or to schedule a consultation and learn what options are best for your home, contact Hoff Heating & AC today.
