Air Conditioners are not Vacuum Cleaners

A dirty subject full of myths & misconceptions...

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Now that I have your attention I would like to remind you to check the air filters. At least after reading this.

While you change the filters I would like to point out to you the importance of them and why they should be changed frequently.

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Purpose

The main reason we change air filters in our comfort systems is to keep the ducts and the evaporator coils clean of debris. It also, but not mainly, helps clean the air we breathe. Think of it as wearing a mask.

Filters should be placed in easy to reach locations, but depending on the year it was originally installed, or functionality of the comfort system itself, it varies to where they are found. They will always be placed before the evaporator coils in a properly operating system.

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Functionality

All filters aren't the same but all brands are. (other then the price) Multiple sizes, ratings and thickness all serve their reasons.

It's good to know your systems correct filter size. If you have a smaller filter installed in place of a properly sized filter, unfiltered air will bypass the filter and mix back into the air stream.

Ratings are measured by the MERV scale. (Minimum Efficency Reporting Value) Basically, the higher the rating, the better air filtration the filter has. It also is important to point out the higher the MERV rating is, the more often you will need to change them in heavily used conditions. They're also the higher priced filters. They will however, remove the smaller particles from the indoor air.

Filter thickness of 4"or more is normally used in multi-air return systems. Meaning, if your system has multiple air return vents, you either change small filters in every room by every 3 months or change one central whole home air filters by every 9-12 months. In short, the thicker the air filter is, the less often you will need to change them. Thin filters of 1" or less will need to be changed every month in comparison.

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The Misconceptions

#1 Dirty homes causes dirty filters.

Not really. We find that wherever there is human traffic, there will be dust stirred into the air stream. There is a reason for the whole isle of dust products at the grocery store. Dust happens. It is more common to see dirty ducts in comfort systems with poorly maintained filter replacement schedules. Professionally speaking however, years of heavy smoking inside or multiple pet homes without proper HVAC maintenance are the worst to keep the cleanest.

#2 Arrows don't matter.

Actually they kinda do. The reason the arrows point in one direction is because of the support system the manufacture designed for the filter. It only goes in one way for this reason. It is designed not to cave in once the air comes on. Although it does not damage the system with extended use if installed backwards, it will cause the filter to cave in and allow unfiltered air onto the airstream. Remember to point the arrow away from you when you install it.

#3 Removes odors.

Unfortunately, they do not. The comfort system is designed to circulate air inside an enclosed space. It cools the air by removing heat. That's it. What is left over once heat is removed? That's right. The more heat that is removed, the colder it becomes. It is the same air as it passed through the filter, but cleaner and cooler. Air returns are never placed near bathrooms, unless you live in a tiny home or loft. Note, charcoal filters are the best at odor control.

#4 It's permenant.

This is a more common 'than you would think' in reponse to my question during a service call "when is the last time you changed your air filters?" Okay, there is such a thing as a permenant filter, but its based on how often it's cleaned, not when it needs replaced. Most home owners that have an electronic air cleaner (Electric Self Cleaning Filters) know they have them and often know that the cells in them still need annual cleanings for proper operation. However, it does not mean your filters never need cleaned if they are washable, or replaced if they are disposable.

#5 It produces dust.

This is the most common misconception concerning comfort systems and air filters. Although, what produces dust is a whole different topic and deserves a scientific explanation, dust will still collect in your home without the comfort system on. It is a common battle in every home. With a properly sized filter, dust will be collected and prevented from being recycled through the duct work. Unfortunatly, It will not collect all the dust in your home. Dust will eventually settle below the airstream of the air conditioner and not being able to collect on the filters. This is why heavy foot traffic areas will cause more dust to enter the airstream and settle again, making it seem like its producing the dust. Your comfort system was designed to condition the air and keep the inner functions cleaned, not clean your home or business.

This is why your air conditioner is not a vacuum cleaner.

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