Changing Your A/C Filter
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Changing Your A/C Filter

by TimJones on January 28, 2010

DSCN3947Changing an air conditioner (A/C) filter usually does not require much technical skill.  Whether horizontal, vertical, or in a ceiling, changing the filter generally consists of unscrewing a couple screws (usually with nice big knobs on them, so you don’t even need a tool), taking out the old filter, putting in the new one and reattaching the panel with the two screws.

So, where do things get complicated?  Well, a couple areas can generate some consternation for the average homeowner.

  1. How often do I change my air filter? — Ah, the age-old debate roars on.  Traditionally, the standard was every 30 days.  Now, with high-efficiency, better quality air filters, you theoretically can go 3 months, 6 months, sometimes more, depending on the type of filter you have with your system.  Ultimately, though the longer you keep a filter in place, the more dirt it holds, and the harder your system has to work to pull the air through the filter, the more dirt that may pass through to the system and your house, etc.  The harder your system works, the more energy it uses and the quicker the mechanical system breaks down.  Additionally, although slight, your unit will use more energy if it’s not efficiently pulling air through that filter.  Many will disagree, but I believe in the old 30 day rule.  For the few bucks that it costs for a good A/C filter, just change it every 30 days.  Keep your system clean and working efficiently.
  2. I need to get that really “high-efficiency, no allergens will ever enter my house” filter. – Again, that filter may trap 99.9% of all allergens known to mankind, BUT – Did you see the big but over there? — but, this also makes your system work harder.  See note above on your system working harder.  I hate allergens and dust mites and all that as much as the next guy.  I’ve had my mornings waking up with a stuffed nose from the dust in the air, too.  I also believe there’s a happy medium to the filter issue.  Get a decent filter, but don’t go overboard and buy the end-all, be-all filter that doesn’t allow enough air to flow to your system.
  3. Filters are designed with a flow direction. Many people don’t notice that big arrow with the words “Air Flow” written next to it on an A/C filter.  Yes, these things are designed for air to flow through them in a specific direction.  Take notice and install it so air flows correctly.

As for changing the filter, here are some more detailed steps for how to change your A/C filter.

  1. Locate the filter. It will always be located on or very close to the “inside unit.”  This part of the air conditioning system is also known as the air handler.  Sometimes, the filter is placed behind a return grill (a louvered, metal grating that occurs near the air handler).  This is most often seen in apartments or smaller homes where the air handler is in a closet and the filter is integrated with the return grill in the door or ceiling.
  2. Remove the panel: Sometimes this is a grill, sometimes it’s just a small panel (like in the video) — every system will be different and newer systems will be labeled.
  3. Remove the old filter: Take out the old air filter and throw it away.  You won’t be needing it, anymore.
  4. Insert the new air filter: Slide or place the new filter in the old filter’s location.  Remember, as I mentioned above, you need to make sure it’s inserted in the proper direction.  The air flow should follow the arrow on the filter.
  5. Close the panel back up: Re-install that panel that you removed in step 2.

Now, you’re all done for 30 days!

Related posts:

  1. Air Filter Problems

{ 8 comments… read them below or add one }

ltbeyer March 11, 2010 at 8:36 pm

So glad you posted this video…I asked my fiance about changing our air filter, and he told me he never has! (He's lived in the condo since August.) I found the air filter last night and it's DISGUSTING. It's now on the honey-do list (along with probably watching your how-to video)!

Tim_Jones March 11, 2010 at 9:27 pm

Hey Lauren,

Yes, he definitely needs to hang out here, a bit. :) Never changed the air filter? 7 months? Lucky his AC still works, especially if it has any age on it.

This is one of the most often overlooked and can be one of the most expensive areas of home maintenance.

Monica MacLeod May 19, 2010 at 9:06 am

Good day. I've been using the Dupont Filtrete filters for about five years and since we run a landscaping business and track alot of dirt in with us at the end of the day, I change out our filters about every three weeks. Within the past couple of years though, I've noticed that the metal mesh within the filter makes a flexing noise similar to water dropping for the first couple seconds after the condenser shuts off. It doesn't make the noise when first installed and also when the a/c is not run for long periods of time, like during the middle of the day. Definitely nothing is leaking and even a Trane representative verified that the noise is made by the filter. Could you recommend a good filter that either doesn't have the metal mesh or one that is sufficient in thickness that it doesn't flex enough to allow this noise to occur? Thank you for your time and help.

Tim_Jones May 24, 2010 at 1:40 pm

Hi Monica,

This required a slightly longer answer, so I made it into a blog post. Here's the link:

RandR92 August 27, 2010 at 1:23 pm

I just moved into a house and noticed that my indoor filters (2) in my ceiling make an annoying suction sound when my A/C kicks on. I replaced the filters and the noise lessened, but it is still annoying!! I have the proper size filter. What can I do?

deepyahuja December 10, 2010 at 2:52 am

these are praiseworthy steps superb thoughts on changing filters benefits. i am completely impressed by your views. it should be cared by people same in home ac filters replacement. due to health purpose it is beneficial.

Don Manning June 23, 2012 at 1:30 pm

Is it better to have a filter on the return vent or at the air handler? I wuould think at the return it would keep the ducts clean but the Carrier unit has it at the air handler.

Katherine July 9, 2012 at 4:42 pm

WOW..I bought my townhouse in 12/2009 and no one told me about the filters needing to replaced every 3 months. I haven’t changed it since I have lived in the place. How do you know what size to get to replace without taking it out first? My A/C unit is hard to get to, in attic and I don’t have a ladder. Looks like I’ll need help. quick!

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