You may not know it, but your air conditioner is one of the most important tools in the fight against indoor allergies. Between their talent for pulling excess humidity out of the air and their ability to help trap mold, pollen and dust particles, central air conditioners are a huge blessing for allergy sufferers everywhere. Below we look at the relatively easy steps to take for creating an allergy free air conditioning system

ac filter in wall return

Indoor Allergens and Air Conditioners

There aren’t many allergens that an air conditioner can’t control with a little help from you. No matter whether your allergies are seasonal or last most of the year, running your air conditioner will help keep irritants out of your home in many ways.

* Preventing Entry

When you run your air conditioner, unlike when running fans, you do so with the windows tightly sealed to keep as much cool air inside as possible. This behavior also keeps allergens out of the house. If your allergies are severe and aren’t restricted to certain seasons, you may benefit from running the air conditioning or the fan in your system even on cooler days. (For additional info, you may check this article >> Ten Facts about Indoor Air and Your Health.)

* Filtering the Air

Air conditioners work by sucking air out of your home through a filter, cooling it and recirculating it again and again. Filters can remove pollen, mold spores and dust from your air permanently, reducing the overall indoor allergen load. Provided you keep your windows shut most of the time, your air conditioner is your best bet for keeping your home as allergy free as possible.

* Decreasing Humidity

A neat side effect of air conditioning is dehumidification, the removal of moisture from the air. When your indoor air is cooled, its ability to hold on to tiny water molecules is reduced, causing it to drop moisture into a pan below your evaporator coil. This water is channeled away, permanently removing it from the air. The drier your air, the harder it is for allergen-producers like molds and insects to thrive.

overhead ac vent register

Keeping Air Conditioners Allergy-Friendly

Even the best of air conditioners needs a little help in the war on allergens. Regular care of certain parts of your system will ensure that your air conditioner can remove as many allergens and indoor pollutants as possible. Check these pieces and parts at least once a month:

* Filters

Check your filters monthly and replace them any time they appear clogged, even if they’ve been in place less than three months. Consider investing in an electrostatic filter — these permanent, washable filters carry an electrostatic charge that attracts dust and other allergens like a magnet.  You only need to pull them out every few weeks and give them a good spray to ensure they continue working well.

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If you’re not ready for an electrostatic filter, look into filters with a MERV rating of 8 or better; although disposable, these filters will trap up to 85 percent of pollen, mold spores and dust.  The higher the MERV rating, the more it can trap, up to a point. Too high of a MERV rating can actually interfere with proper air handler functioning by choking back the air supply.

* Ducts

Brand new ducts are a beautiful thing, but most people don’t live in new houses.  When you start to notice a lot of dust blowing out of your ducts, it may be a good idea to have them cleaned professionally. Otherwise, make a point to remove your registers and vacuum them out as deeply as you can at least once a month. Small filters can be fitted over the registers to catch dust that’s inside your system, but make sure to keep these clean for best results.

Ducts that seem to be constantly full of dust may have bigger problems than a little bit of trapped dirt. Check your ducts regularly for cracks, broken seals and rusted areas where dust may be sneaking into the system. A little duct tape, a new fitting or short section of duct can work wonders at stopping dust from entering your living space from your attic or crawlspace.

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* Condensation Line

Clogged condensation lines will increase indoor humidity, no matter how much you run your air conditioner — that’s how mold colonies get a foothold, so check yours at the same time you do your filter and ducts. Remove it from the system, pour a little water in and make sure it comes out the other end, rather than filling your line up.

You can treat your condensation line with a little vinegar or bleach water to kill black algae colonies that might be blocking proper flow. If you find yourself treating the line frequently, consider installing a removable cap near where it enters your furnace to simplify this chore.

insulated ac duct at air handler


Stefanie Miles writes for Precision AC, a leading HVAC, plumbing, and electrical company in Phoenix, Arizona. For more from us on Indoor Air Quality and HVAC systems in general, see our category, HVAC. Cheers. ~jb, Editor – BuildingMoxie.com.