Spring has officially sprung here in Texas, and even if your hometown’s still under the Groundhog’s curse for a few more weeks, you’re probably considering replacing those nasty, wintrified heating and a/c filters in your home. Realizing that waking up every day with a stuffy nose may be due to my crap-clogged filters, I hit the big box on a mission. Unfortunately when I got there and saw 300 varieties of air filters ranging from “high performance electrostatic” ($$$$) to fiberglass ($), I realized I needed some guidance. Here’s what I learned.
To make sure you’re selecting the appropriate kind of air filter for your home, consider whether any pollutants (indoors, in your garage/shop, or outdoors) are affecting the air quality inside. Household chemicals, pesticides, mold or mildew, high humidity, improperly vented appliances, standing water or leaks, or (obviously) if anyone smokes inside the house are factors that can be identified and fixed first.
Second, assuming your home filters are designed more for providing healthy air in the living space (as opposed to protecting machines or equipment), take into account how you or your family responds to allergens such as dust mites, pollen, mold spores, smoke, pet dander, and smog. The better quality the filter, the smaller the particles it can capture, and without interrupting the air flow of your HVAC system too much, which is paramount for efficiency. Also, check the MERV (Minimum Efficiency Reporting Value) of the filter: they range from 1-16, and the 12-16 range are the highest quality at 90+% efficiency.
Home air filters are divided into six basic types:
1. Electrostatic air filters – As air passes through the filter, a static charge is created that attracts contaminants. Electrostatic filters are very efficient, provide an excellent balance of efficiency and performance, and are designed to replace panel- or frame-style filters you already use in your HVAC system. They often run at or above 90% efficiency or a MERV of 12-15 (compared to 10% for fiberglass), and come in permanent or disposable types. They can be pricey, running around $70, but they do the job well.
2. Pre-cut or bulk roll media air filter pads – Used mainly by HVAC professionals, media air filters have a very high capacity for capturing particles (up to 30 times more capacity than fiberglass) and the pads can be changed out regularly to fit in a single aluminum frame. The pads are made from dry-tack polyester and are disposable. Media air filter pads are not widely available but can be ordered from web sites such as RiteAir.
3. Pleated air filters – Popular because of their durability and affordability, pleated filters are widely available in a variety of (even oddball) sizes and are one of the HVAC industry standards. Some include electrostatic fibers or carbon or charcoal fibers for odor control. MERV ratings for pleated filters range widely from around 5 to 12; for allergy sufferers the 10-12 range would be best.
4. HEPA air filters – To qualify as HEPA (or high efficiency particulate arrestance), a filter must capture at least 99.97% of particulate matter 0.3 microns in diameter. HEPA filters are used in hospital and surgical rooms or other places where clean, particulate-free air is essential. They have the highest filter capacity of all, but require a lot of maintenance since dirty HEPA filters significantly reduce airflow and can cause HVAC system problems if not kept clean.
5. Activated carbon air filters – Activated carbon is charcoal treated to cause millions of pores to form, increasing surface area. Usually carbon filters are added to another type, such as media air filters, because of their ability to remove odors from smoke, chemicals, gases, and other odor-causing substances around the house. They are not recommended in combination with HEPA filters because HEPAs already reduce airflow.
6. Fiberglass panel air filters – Very inexpensive and (unfortunately) commonly used, “blue” fiberglass filters basically capture about as much dust as chicken wire and leave particles of crap blowing around your HVAC system, in your lungs, and in all your equipment too. It’s best to avoid these if at all possible.
The bottom line? If allergies are a major concern, air filters are probably just one step you need to take to improve air quality in your home, but for the highest quality, go with electrostatic filters, and get the permanent ones like the Boair 5-stage if you can afford it. If you just want a simple, decent quality disposable air filter, I’d go with the pleated filters from 3M’s Filtrete with electrostatic treatment. They range from $7-30 each depending on size and quality, and need to be replaced every 3 months or so.
Filtrete Filters Via Amazon [What’s This?]
Filtrete Filters Street Pricing [Google Products]
Guide To HVAC Filters [Furnace Filter Care]
EPA Guide to Air Cleaners In The Home
Article: Understanding Minimum Efficiency Reporting Value (MERV)