The air filters in your heating and air conditioning system can be a great way to enhance the quality of the air inside your home. These filters are designed to stop particles from entering your house and the air you breathe, and they can be especially helpful in eliminating allergens like dust mites and other health-harming particles. The California Air Resources Board and the Appliance Manufacturers Association both have lists of air filters that have been tested and proven to emit little or no ozone. In general, the higher a filter's rating on a scale of 1 to 16, the more particles it can filter out of the air.
It is important to note that ozone generators sold as air filters should be avoided, as they can actually worsen indoor air quality. Additionally, it is always important to reduce or eliminate sources of indoor air pollution and to ventilate with clean outdoor air. The EPA's minimum efficiency values, also known as MERV, describe the ability of a filter to capture particles larger than 0.3 to 10 microns. This can provide useful guidance for comparing different filters for your air conditioning system.
It can be difficult to know if a system can use a higher-efficiency filter, as air conditioning systems aren't usually labeled with any filter recommendations. Activated carbon filters can be effective, provided that a large amount of material is used in the filter. However, these units typically have limited filtration capabilities and are designed more to keep the interior of the air conditioner clean rather than removing fine particles from the indoor air. Some washable filters aren't much better, but high-end permanent filters can rival the very common disposable pleated filters, which are available in a range that even reaches MERV 12 or higher. To remove small particles, choose a portable air filter that has a high CADR for tobacco smoke, which represents the smallest particles.
The cheapest disposable fiberglass filters only meet the minimum (or slightly better), around MERV 2 or 3, and are designed to protect the inner workings of your air conditioning system, rather than indoor air quality. However, proper household air filtration requires that you change your home's air filters regularly before you begin to see evidence that it's been a while since you changed them. When it comes to improving indoor air quality in your home, investing in a high-quality furnace air filter is an excellent way to start. Not only will it help reduce allergens and other health-harming particles from entering your home, but it will also help keep your HVAC system running efficiently and effectively.
