Filtering the Air for Efficiency and Health
Let’s start out by stating the obvious: HVAC filters are about the least sexy home maintenance expense we can think of. You don’t get the excitement that comes with buying a shiny new tool or the satisfaction you feel while admiring your clean floors after mopping. Air filters don’t have fun names and attractive designs, and we don’t even get to see them at work or the results of their work. Boring! But what air filters lack in excitement they make up for in doing some heavy lifting that affects your entire home.
Did you know air filters were originally only meant to protect the furnace and not people? Without filters, airborne debris eventually builds up inside the furnace which causes performance issues and eventual breakdown. And initially, air filters were a one-trick pony – capable of preventing relatively large particles from gumming up your furnace and nothing more.
Through innovations in air filtering technology, air filters now include the added benefit of improving our ionizing wir . Now, not only do our air filters prevent our HVAC systems from dying and keep them operating efficiently, but filters also help us prevent illness and discomfort, especially those among us who have allergies.
What Filters Are Right for My Home?
There are several factors to weigh when you’re selecting your filtration, including cost and efficiency. But one factor that you cannot overlook is whether someone in your household has allergies or other respiratory issues. The more sensitive a person is to allergens or the more severe the respiratory problem, the more you need to ensure you’re using high-efficiency air filters. So, let’s start by talking about our first factor: efficiency.
Efficiency of the Air Filter
We’re talking about efficiency first because we believe it’s the #1 thing you should consider when selecting air filters, as it has the biggest impact on your system and your health. Air filter efficiency is measured in MERV – minimum efficiency reporting value – which is a scale of 1-20, where higher numbers are more efficient. The size of the particles (or more accurately, lack of size) the air filter can capture determines its efficiency rating. That is, more efficient filters trap more particles because they’re able to capture smaller particles, which are measured in fractions of microns!
In short, the smaller the particles a filter can capture, the higher the efficiency and effectiveness of the filter. When you shop for filters, check for the filter’s MERV number, keeping in mind that commonly used residential filters have an MERV range of one to eight. However, filters with higher ratings, ranging from 10 to 16, are available for residential use. For example, high-efficiency particulate air (HEPA) systems, like this one from Lennox, use hospital-grade filtration technology with a performance that’s equivalent to a MERV 17 filtration efficiency or higher.
Higher filter efficiency keeps prevents your furnace from breaking down, provides you with healthy clean air, and it improves airflow, as well. Typically speaking, more efficient the air filter, the better the airflow will be.
Cost of the Air Filter
Air filters can range from a couple of bucks to $100 or more! Efficiency is one element that affects the cost of the filter, but another is how long the filter can be used in your system before it must be replaced. The initial price of a high-efficiency, long-term filter might be steep, but those filters can save you money over the long-term. At the same time, inexpensive filters may not provide the level of filtration you need and may also require frequent filter replacement.
Of course, the cost of heating your home and maintaining your furnace isn’t the only cost to be considered. As mentioned above, high-efficiency filters are a must for those with respiratory issues or allergies. When you consider the health care expenses – not to mention lost time – investing in a higher-quality air filter will likely cost significantly less overall someone in your home has a respiratory issue.
Type of Air Filter
The efficiency and cost of the air filters you select are determined by what the air filters are made of. There are many types of air filters, but they tend to fall into one of these main buckets.
Filters that use fiberglass or other synthetic fibers to filter the air are a cheap and disposable option for your furnace. They filter out as much as 80% of particles 50 microns and larger plus 25% of particles between 3 to 10 microns. We’d call that minimum protection, as it’s just enough to prevent dust and dirt build-up on fan motors, heat exchangers, and other furnace components. These filters will keep your furnace clean by trapping the large particle, and you’ll have maximum airflow through your system, but these filters won’t remove airborne contaminants that can affect your health.
Denser than fiberglass, filters of polyester block are capable of blocking more contaminants because they capture smaller particles. Polyester filters trap and eliminate 80% to 95% of particles 5 microns or larger. They typically cost fours times more than the average fiberglass/synthetic filter, but they offer far more protection against pollutants that impact your health, especially if they are pleated (see below).
The fibers in these filters are self-charging, and the charge attracts particles out of your air. There are disposable and washable version of electrostatic filters, and what you need may depend upon your furnace. Disposable electrostatic filters typically have higher MERV ratings that the washable versions. However, the washable electrostatic filters are far more efficient than fiberglass or polyester filters, plus they last a good bit longer than the average filter. Only soap and water are needed to clean these filters. They must be allowed to dry completely after washing, as reinstalling them before they are completely dry can lead to mold and mildew growth.
The pleats in these filters provide additional surface area upon which particles can be trapped, which ups their efficiency significantly. They offers high-efficiency results because they can trap particulates 0.3 micron in size, including pollen and germs (bacteria and viruses). Pleated filters are more efficient and last longer compared to fiberglass/synthetic filters. Plus, they filter out more pollutants from your air, but they don’t reduce the airflow within your system.
HEPA, which stands for high efficiency particulate air, filters trap almost everything. They’re capable of filtering out up to 99% of particles 0.3 microns or larger. They are the best for removing pollutants from your indoor air and maintaining a healthy environment. However, they tend to dramatically reduce your system’s airflow, which makes your system work harder, driving up your energy usage.
Additional Clean Air Solutions
If you’re really invested in having the best indoor air quality possible, there are other products you can invest in. For example, germicidal lights, like this model from Lennox, also purify the air by using intense ultraviolet light that sterilizes surfaces.
Another option is an electronic air cleaner (EAC), which removes impurities through several steps. First, it takes recirculated air and passes it through a prefilter, which traps large pollutants. Next, smaller particles that make it through the prefilter are given a positive charge. Finally, a negatively charged collecting section attracts and then captures the particles!
To find out which air filter choices are best for your system, your home, and your health, or to explore any additional air purifying options, give us a call today. One of our certified technicians can visit your home and assess which filters and/or air quality options will provide the best solution for you.