Why Air Filters Are a MustWhen your home starts to look cluttered, or unpleasant smells start to waft around the room, you know it’s time to clean. But alongside your cleaning to-do list, do you remember to change out air filters? Changing your system’s filter on a regular basis is just as important as keeping the rest of your home clean to help:
- Prevent damage to your HVAC system: A buildup of dirt and debris can cause damage to your unit by clogging the fan, coils, and condensate drain lines. It can also attach to electrical wiring, and other critical parts. Dirty wiring can stop the flow of electricity, causing electrical gear to overheat. This can age your unit prematurely, affect its overall efficiency, and even cause it to stop working altogether.
- Stop dangerous contaminants from circulating through your home: Air particles that find themselves in the return duct of your air conditioner will eventually be spread to every single room in your house—including contaminants considered toxic or hazardous by the California Environmental Health Tracking Program (CEHTP). Keep in mind that rooms requiring more sterile environments, like baby nurseries, will experience the same air quality issues as the rest of the house.
- Inhibit the spread of allergens: Pollen, pet dander, and mold are all allergens that migrate into your home from the outside. Once they find their way in, your air conditioner or furnace can quickly push them into each room through the duct system, kicking allergy responses into high gear.
MERV Air Filter ClassificationsThere are many types of air filters, but all you need is a good MERV-rated filter. The Minimum Efficiency Reporting Value, or MERV, is a rating designed by the American Society of Heating, Refrigerating, and Air Conditioning Engineers. The 4 MERV ratings most applicable to your home AC or furnace are:
- MERV 6: This filter has the least amount of filtration, catching only between 20-69% of all large particle contaminants. These include lint, household dust, and pollen. This should only be an option if it is the largest filter recommended for your air conditioning unit.
- MERV 8: This is the most standard size of filter for residential homes. They can capture up to 85% of all large particles and 50% of smaller ones, like lint, household dust, pollen, and mold spores.
- MERV 11: This is a superior filter rating that captures over 90% of large particles and between 70-90% of the smaller ones, including all the particles that MERV 8 filters can capture, plus pet dander and some smoke. If your air conditioner motor can work with a MERV 11 filter, it’s a great choice for homes with pets, or kids prone to allergies.
- MERV 13: This is the highest filter rating available for home air conditioners—and the best option for households with sick family members who need a sterile environment. These filters are usually used in schools and office buildings, and are capable of filtering over 95% of large particles and over 80% of small ones, even some bacteria and viruses.
Choosing the Right MERV Filter for Your HomeThe three factors you should consider before choosing your next air filter are:
- The size of filter recommended for your unit: Some older HVAC units may not be designed to fit the 2” filter widths of many highly rated filters. These systems can usually only accommodate the MERV 6 or MERV 8 filters with a 1” filter housing that you find at your local grocery store. However, you can order different sizes of MERV 11, and even MERV 13, filters online, or ask your local HVAC professional to recommend a supplier that carries them.
- How high of a filter rating your unit can support: Higher ratings usually mean at least some reduction in airflow, so you could end up overworking your system if you install a highly rated filter. The harder your unit works, the higher your energy bills—and future maintenance requirements. But, if your unit has an ECM, or variable speed motor, a highly rated filter won’t affect the airflow.
- The cost of the filter: The better the filter, the more you are going to pay. You may think you can’t put a price on your health, but considering air filters need to be replaced every 1 to 3 months, at minimum, it’s certainly something to consider. You’ll pay between $6-8 apiece for most MERV 6 and MERV 8 filters, but the highly rated MERV 11 and MERV 13 filters can be nearly double the cost at $10-15.