When Should I Change My Furnace's Air Filter?

February 26, 2015

Sometimes we’re asked what is the number one thing that Gaithersburg area homeowner's can do to protect their air conditioning and heating system between their scheduled PLUS Maintenance Tune-ups? The answer is simple this; remember to change the heating and air conditioning air filter. Replacing furnace and return air filters is crucial to the ideal operation of your HVAC system, as well as your home's air quality. Research suggests that indoor air pollution is one of the top five environmental health risks? You probably don’t consider it as you sit and watch TV, but this is the air you breathe day and night. Changing the air filters is not a tough thing to do for most Gaithersburg homeowners, but there are usually two challenges to actually completing this job:

  1. Knowing just how often to replace your furnace or air conditioner filter.
  2. Changing them when you’re suppose to.

When To Change Your Air Filters

Most filters have a timeline printed on the box or plastic. It may instruct "Lasts up to 3 months" or "Change filter every 90 days". Look around at the store and you'll notice that some are meant to only last a month, while other manufacturers (like Honeywell) have produced media air cleaners with filters meant to be exchanged once every 6-12 months. The standard seems to be once every three months for most higher quality filters, but we have a rule of thumb that we recommend our customers to go by. If they're dirty, change them! A dirty air filter can exacerbate or cause damage to pricey equipment, like your compressor, so it's best to change it out more often than neglect it. If you want to follow the manufacturer's recommended limit, we suggest marking the date on the filter when you swap it out, and programming a reminder for yourself in your phone or on a calendar. Also be aware that your filter manufacturer sometimes has a different recommendation from your HVAC system manufacturer.

Determining how often to change your air filters can depend on several factors:

  • The type of air filter you are using
  • The collective air quality of your Gaithersburg area home
  • Pets – Cats, dogs, birds, etc.
  • Number of occupants in the house
  • General air pollution in the Gaithersburg area or construction taking place nearby

For the common 1"-3" air filters, the manufacturer specs basically say to change them every 30-60 days, which is really a great rule of thumb. Still, general guidelines are not applicable to all. If you put up with light to moderate allergies, you might require an upgraded air filter or change them even more often than OEM specifications. On the other hand, if you're in a less populated area, own a less occupied home (like a vacation home) or an area with few automobiles and trucks, replacing your air filters each year may be quite sufficient. Why do we call out our beloved pets? They have a tendency to shed, which can clog your air filter quick. Obviously, the air filter is just doing its job by trapping pet hair and dander, but exceptionally dirty filters can cause diminished HVAC performance.

In summary:

  • Seldom used home or single occupant homes without pets or allergies: Change 6-12 months
  • Common suburban home without pets: Change every 90 days
  • Got a cat or dog: Change every 60 days
  • More than one pet or have allergies: Change every 30-45 days

How To Remember To Change Air Filters

Here’s an easy way to stay on top of this; sign up for the Service Experts Email Club. When you do, you can elect to receive (or not) great email coupons and newsletters with a lot of tips and discounts on AC repairs and tune-ups. But wait… there’s more, your email subscription preferences let’s you set a reminder to change your Gaithersburg area home's air filter every 30, 60, 90, 120 or 365 days, or any date you find most convenient.

How to replace your return air filter

Most of you know how to replace the air filter in their unit, but some houses have an extra filter in the return ductwork. Whether you have one or not is dependent on which HVAC system you have. Your unit is designed to handle a certain amount of pressure in your home sweet home, and the more filters you have the fiercer the blower motor works, which can shorten the life expectancy of your system if it isn't designed for it. Learning whether you have a return filter and replacing it is simple:

  1. Find your return air vents.
  2. Some covers have screws and some have tabs. Unscrew or pull tabs to pull off the wall.
  3. Look for a filter. If one is inside, pull it out and note the size.
  4. Verify the filter type is the one recommended by the manufacturer.
  5. If filter is dirty, replace with the manufacturer's recommended filter of the same size and type.
Crazy as it may seem, filters can greatly alter your home's airflow, which is why we recommend referring to the manufacturer. A higher quality HEPA filter that is designed to catch tinier particles will restrict airflow more than a cheaper filter. With restricted airflow comes greater pressure on your system, so you need to verify that your HVAC system was made to handle it. Otherwise, you may experience lowered heating and cooling efficiency in your home, and unit parts may wear out much faster than normal.

 

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