Air flow efficiency of an air conditioner filter is something that’s constantly changing. If it doesn’t, then you’re either not using a filter or your filter simply isn’t working. It will constantly change over any period of time. The efficiency changes because of one reason: it starts to get loaded down with particles (dust, pollen, mold spores, pet hair, your hair, bacteria, lint, and the list goes on) until basically all the openings that air was once flowing through become clogged. The end result is that you have better filtration but the negative impact of this is that the air flow through the filter is drastically reduced.

When a reduction in air flow occurs in your filtration system, it makes the air conditioning system actually work harder than it should have to, making the unit less energy efficient than it could be. It has to work harder because it has to pull more air through smaller openings to push through the system and into the rest of your home. This makes it harder for the system to keep your home cool.

Picture it like this; say your air filter is a marathon runner getting ready to start a big 26 mile marathon. When it first starts the race, it sets out on a nice even pace, very efficient, very fluid in form, working at the top of its game (this is when the air filter is first installed in your cooling system). Somewhere along the route it begins to break a sweat and starts to feel the burning in its legs around mile 5 (this is a few weeks into the filtration process and it’s started collecting all these disgusting little particles in its media making your cooling system work a little bit harder). Around mile 15 its arms begin to get tired from working trying to keep form and push it along a little further in the race (this would be around a month and that air flow is becoming even more constricted due to the amount of debris still piling up on its surface). Mile 20 becomes the breaking point. Do you stay the course and finish the race as its only six more miles and you’ve already ran 20, would be pointless to quit now. Your air filters saying the same thing. That little 1-inch filter has exhausted almost all air flow opportunities within it but it’s still working and the filtration is actually getting even better as there’s not a lot of places for the new stuff to flow through. But it’s definitely getting a lot less efficient and making that system use more resources and work harder to keep that cool air pushing through the system. You finally cross over the finish line and 26 miles of pure unadulterated exhaustion is over. Month 3 rolls around and your filter has finally thrown in the towel and your AC is on the brink of crying from all the work that “good” air filter has been making it do over the past 3 months.

The longer a filter sits in a system, the better filtration it will have, but the less air flow and reduced energy efficiency it will provide.

Now think of it in these terms, that’s only a 1-inch pleated air filter that’s manufacturer rated for 3 months (most need to be changed sooner but are not because it says every 3 months). What if you could increase your air flow by 40% and increase the life of the filter by 4 times up to 12 months. That air conditioning system would work less, be more energy efficient and receive much more air flow.

If your HVAC ductwork is dirty, you can be in line for a whole host load of problems. The main way, or really the only way, to keep your ductwork in proper order is to do adequate filter maintenance. If your filter is not functioning properly, you could get dirt, dust , pet hair, grime and whole bunch of different allergens sucked right up into your ductwork. The problems come, and especially if you live in an area that is already humid, when that humidity falls to a point where condensation can gather. You’ve heard all your local weathermen talk about that dewpoint. That’s when growth can occur and before long you’ll have bacteria and mold sprouting all over the place.

And if it’s a residential or commercial, typically more prevalent in the commercial environment, if it has had some form of acoustic lining or acoustical duct liner installed, you could really be in a world of hurt. These do nothing more than try to drown out the background noise coming from an HVAC system. Some of these will also add an extra layer of thermal insulation to your ductwork.

This is why you should be taking the appropriate measures to change out your air conditioner filters regularly and frequently. As an added little tidbit, if your filter ever gets wet due to the condensation gathering or falling on it from the ductwork, it should be changed immediately. This could lead to growth starting to actually occur on the filter as well and particles being distributed through your ductwork.

Another major factor, especially if you use those cheap air filters you get in a three-pack off the store shelf for $5.00, is that if these are left in the system to long, they are not strong enough to handle the air flow and will eventually collapse at the sides. In essence, the air filter gets sucked in. This lets the air bypass the filter media in the return air grill and flow straight through the ductwork back into the coils of the cooling system without any hindrance whatsoever. This could cause some serious damage not only in your ductwork but also to your air conditioning system and air quality in your home.

You should find every way available to make the job as easy as possible to change your air conditioning filter. One helpful little tip to guide you along the way is get some labels and permanent markers or sharpie’s. When you change out the filter, write on the label the type, size and date you changed the filter. Then stick this in a visible area on the return air grill so you can see it and as you pass by you’ll be able to visibly see the last time you changed the filter. And if you change filters, note the pressure drop to your ac system. Some people actually write this info on the filter but that tends to be a little useless as you won’t be able to see it.

Changing an air conditioner filter is a thankless job and nobody really wants to do it.

Add to that the location of your return air grill. If your return air grill is located in a not so desirable spot that tends to be a little hard to access, you can bet that you will be less likely to do the proper maintenance on it and will more than likely suffer from poorer air quality in your home and air ducts. Also, if the grill actually bolts to the wall or ceiling instead of using a quick-release type system that’s hinged, you’re likely to fall into the same category.

Above all, when changing an air conditioner filter, make sure you get the right size. Shop around and check out all the different performance ratings and specifications to see that you won’t suffer an issue of pressure drop throughout your system by installing an inadequate air filtration filter. You will be surprised at what you find but keep in mind that greater resistance will mean less air flow that could negatively impact not only your energy efficiency and monetary savings but the actual unit itself.

One great product we have found is the SmartFilter by ConversionAire. This filter takes all of these things into consideration. In fact it was designed by someone in the air filtration business in a hospital bed where he had nothing better to do than think of all the things wrong with the filtration industry today and put that thought into creating one of the best HVAC filters on the market.

I’d like to take a minute or two to discuss 1-inch pleated HVAC Air filters as they are some of the most common air filters on the market today. Not only are they so readily available at almost all your local home improvement stores, Targets, Wal-Marts, etc., they are also some of the most ineffective types of HVAC air filters that you could buy over the counter. Stores of this nature have a lot that they have to deal with and shelf space is a major concern. So of course, they are only going to supply you with some of the least cost (to them) inhibitive air filters and quite frankly, only a select few that “fit” their shelving plan. Yeah, sure there cheap, can usually pick up a 3-pack for under $40 depending on brand and quality, but what good is it really doing you, it’s not catching the amount of dust particles, mold or pollen that it should be and can actually make your air conditioner system work harder and longer than it should. Not only that, in a short period of time you’ll be right back dropping another $40 on some replacements.

But, if you absolutely must stick with these type of filters then you should know a few things. 1-inch pleated HVAC air filters need to be changed regularly, like clock-work. Their typical lifespan is only about 1 month, you might get 2 out of them but I wouldn’t push it. Sometimes depending on how dusty it is in your home or due to other environmental issues like air quality or the type and brand of filter, you might even need to change them more frequently than monthly. This could be especially true if you are the type of person who likes to keep the windows open to feel the cool gentle breeze of outside air flowing through your home. Or you might just be a dog or cat lover, these pets can wreak havoc on an air filter and definitely shorten the life of any filter causing much more frequent change routines. And if you don’t change them in a timely fashion, you could end up costing yourself a lot more money than you ever thought you had saved.

What could happen if I don’t change the air filter?

Well, there’s quite a few things that could occur if you don’t change your home air filter and the end result is typically one or two things. Not changing them could affect your health conditions and it could end up costing you quite a bit of money in some costly repairs. As I’ve said before, not maintaining and changing your air filter could lead to some very poor indoor air quality which could lead to other health issues. But let’s talk about the part that tends to hit home the most. It could actually cost you money you could be saving, which everyone knows we sure need in this economy. It definitely makes your air conditioner much less efficient than it could be. Those dirty air filters do nothing more than restrict the air flow going through your air conditioning system. This, in turn, makes your air conditioner work much harder and longer than it should and could lead to parts or the entire system wearing out and breaking down much earlier than expected. This does nothing more than lead to costly repairs, and as everyone knows, comforts not cheap.

If you want to prolong the life, reliability and efficiency of your air conditioner as well as increase your households comfort level, you’ve got to regularly replace those air conditioner filters.

How to change the air conditioner filter

• First, find out where the filter is housed in your home and get the correct 1-inch pleated filter size simply by looking on the side of it.
• Buy a replacement pleated air filter in that same size.
• Keep a record or tracking system in place so that you can do proper maintenance on these kinds of filters. Some people actually just write down the date on the cardboard frame of the replacement air filter before installation.
• Remove the old 1-inch pleated air filter from the intake area. (Don’t remove it until you have a replacement air filter to put in it’s place as leaving this area open can lead to additional dust particles entering into the coils of your air conditioning system)
• Put the replacement filter in its place. Be sure to note that some of these filters have specific directions as to which side the air should flow thru to keep the frame stable. There’s another little tidbit as to the problems with the air filtrations industry. Why should it matter which side the air flows through? You certainly don’t have this problem with the SmartFilter nor the changing regimen.
• Dispose of the old filter properly.

And that’s it. That’s really all there is to it. I know, it’s not rocket science by any measure but it will sure go a long way in keeping your health and your air conditioning systems health in order.