Air Conditioning Filters: Everything You Need to Know
Air conditioning filters can be a bit of an enigma to the average homeowner. If you’ve ever taken a stroll down the air filter aisle in your local home improvement store, you will find a dizzying array of options. Air filters come in different sizes, types, and efficiency ratings. How do you choose the right filter?
Selecting a filter depends on your priorities as a homeowner. For example, are you interested in taking extra precautions for health reasons like COVID-19? Or perhaps you’re looking to save money on air conditioning energy bills. Selecting the right filter is an important measure to take in reaching your goals.
You should pay special attention to the following items:
- Filter Type
- Filter Efficiency (MERV, HEPA, etc.)
- Filter Size
Types of Air Conditioning Filters
The typical home in Georgetown, Round Rock, and surrounding areas has an air filter rack within the heating furnace. However, some homes have HVAC systems that are outside the norm, like a ductless HVAC system. So before you go shopping make sure you know what kind of heating and cooling system is in your home.
- Flat Panel Filters – Flat panel filters are usually a fiberglass material. Their appearance is flat, fuzzy-looking media, sometimes reinforced with a metal-like grating. These filters are usually the cheapest, but come with the lowest efficiency ratings.
- Pleated Filters – Pleated filters have a folded soft medium, typically made of polyester, to give it an accordion-like shape. The pleats mean that there is more filter surface area in the same amount of space as a flat-panel filter. The result is higher efficiency levels.
- HEPA Filters – High Efficiency Particulate Air (HEPA) filters have a similar look to pleated filters, but they are made of different materials and in larger sizes. HEPA filters are common in commercial spaces that require a high level contaminant control, like hospitals and research laboratories. HEPA filters aren’t suitable for residential homes because they require a commercial-grade fan to pull air through them at the proper airflow rate.
- Washable Filters – Reusable, washable filters are very durable and can last much longer than a typical flat-panel or pleated filter. These filters require continuous care and maintenance. Washable filters are most commonly used with ductless mini-split systems.
MERV Ratings, HEPA Filters, Air Purifiers, Oh My!
Air filters serve many purposes. Besides keeping air clean for us humans, a furnace air filter helps keep dirt and dust from getting into the tiny mechanical components of your HVAC system.
The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) has a rating system called the minimum efficiency reporting value (MERV) to distinguish the level of effectiveness of different filters.
MERV ratings range from 1 (lowest) to 20 (highest). In general, a higher MERV rating means a higher-quality filter. As the homeowner, you can choose what level of MERV filter you want inside your HVAC system. A typical residential HVAC system can function properly with filters of MERV 1-13. At DTC, we recommend sticking with filters with MERV 6 and above.
So what about filters higher than MERV 13? Filters with higher MERV ratings require a greater amount of airflow to pass the air through the media. HEPA filters, for example, offer filtration of MERV 17-20. Most residential HVAC systems do not have the horsepower to pull air through filters of MERV 14 and above. Installing a filter with a MERV rating that is too high can cause other problems, like increased energy consumption and poor cooling and heating performance. For this reason, we recommend staying at MERV 13 or below.
If you really want to improve your indoor air quality (IAQ), we suggest adding an air purifier to your system. An air purifier can be used in tandem with an air filter and will not have any negative impact on your system’s performance. We recommend the MicroPure Air Purifier by Dustfree, which uses NASA technology to effectively sanitize the air. We can install one of these air purifiers right inside your existing ductwork in just a few hours. Call us for more info: 512-887-5091.
Filter Size Matters
Make sure you buy a filter that fits! Most filters have the exact filter size printed on the outside, so you can buy exactly the same size. We cannot emphasize enough how important it is to buy a filter that is the correct size. A filter that is too small will not sit properly in your system. A filter that is too thick won’t fit inside your furnace. Don’t “stack” filters in order to increase the thickness; this may cause performance issues.
How Often Should I Replace my Filters?
Filter replacement depends entirely on your family situation and personal preference.
If your family has allergies, young children, elderly, or pets, we recommend changing your air filter every two months. Replace it more frequently if allergy symptoms are more chronic. For pet lovers, keep in mind that pets shed most in early spring and fall, so for the best IAQ make sure to replace monthly during those times.
If these scenarios don’t apply to your family, you can safely replace your air conditioning filter every 90 days. Set an alarm on your phone or put a note on your calendar as a reminder. Some smart thermostats even come with filter change reminders which can be sent to your email inbox.
Finally, consider how your indoor activities impact your air filter. You might consider replacing your air filter right after:
- Someone in your home recovers from an illness
- A large gathering where there is a lot of movement between indoor and outdoor spaces
- Home improvement projects
- New furniture has been in your home for about 2 weeks
If you have any questions about HVAC filters, don’t hesitate to give our team a call. We can recommend the best filter for your home and install air filters if you don’t feel comfortable doing it. We are available anytime at 512-887-5091.
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