Everything You Need to Know About Air Filters

Many people underestimate the importance of changing the air filters in their home regularly. For most, it’s out of sight, out of mind, even though changing them is really important. Air filters work with your HVAC system to purify the air circulating through your home. When you tell your thermostat that you want to change the temperature in your home, your HVAC system sucks air from a room, then runs it over coils to heat it or cool it. The air is then blown back out into rooms throughout your home. Air filters are positioned at the point where the air is pulled into the HVAC. It traps particles such as; dust, mold, fungal spores, pet dander, and fibers before they enter your system. This keeps your coils clean and prevents clogging. Damaged coils cannot properly heat or cool the drawn air, so checking your air filters every month is essential.

What kind of air filters are there?

Air filters come in many shapes and sizes. Most HVAC systems use a standard fiberglass filter. These are very porous and best for airflow. Air filters can also come in more dense varieties. A filter’s MERV rating can help you determine the number of particles the filter can remove. MERV stands for Minimum Efficiency Reporting Value and typically ranges from 1 to 16. The higher the number, the more particles it can capture. The cheaper, fiberglass filters, as mentioned above, usually fall around a 1 but can go up to a 4. The best bang for your buck lies in pleated filters. The pleats create a larger surface area, so they are able to hold more particles than a flat one. These filters are usually a MERV 3 and above.

Just because an air filter has a high MERV rating doesn’t mean it is the best option for your system. High rated air filters also come with a downside, poor air flow. Have you ever worn a dust mask before? Think about the difference in what it’s like breathing through a mask vs. without a mask. Your HVAC works in much of the same way. The thicker the air filter, the harder your system has to work to get the air circulating. This can very quickly drive up your heating and cooling bills, especially during the peak of summer and winter. So while a MERV 13 filter may be trapping 95% of air-born particles, it also exhausts your system more quickly which can lead to overheating or freezing up, and a visit from us.

What other factors do I need to consider?

There are a few environmental factors you may want to consider when purchasing an air filter. These can also affect how often you will need to change your filter. Let’s consider a few:

  1. Do you have pets or children? Pet dander is one of the most common allergens. Pet hair and dander will definitely clog up your filters faster than a non-pet owner home. The number of people in your home also means more air-borne particles floating around, resulting in more frequent filter replacements.
  2. Where do you live? Do you live in a part of the country notorious for pollen or dust? Then you will probably need to change your air filter more often or consider a mid-level filter during spring months.
  3. How often are you running your HVAC? Some areas with a milder climate only need to use their systems a few times a month, bi-seasonal areas a few months out of the year, or other people may keep theirs going all year round. The more you are using your system, the more frequently you will need to change your filters. The less you use it, the less you need to change it.
  4. How big is your system compared to the size of your home? If you live in a small home and have a typical sized filter and system you may need to change it less often. However, if your small home also comes with a smaller filter and system, you could end up needing to change it just as often as someone living in a bigger home.
  5. Do you have severe allergies? The only time a high-level MERV filter is recommended is if you have severe allergy issues. Since these filters have so much potential to drive up your energy bills and wreak havoc on your system, is it not better to purchase them unless you have serious health problems. In fact, a study done in 2015, showed that participants with chronic respiratory diseases were the only ones that showed any improvements using these kinds of filters.

So put simply, the best thing you can do for your health and your system is to check your air filter every month, replace them if they are dirty, and be reasonable when selecting the type of filter for your lifestyle. If you haven’t checked your air filter and your system isn’t running as it should, contact us or give us a call at 301.368.8909.

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