Air filters are considered one of the most important parts of an HVAC system, and rightly so. They are the ones standing between the dirty unpurified air of the great outdoors and your fresh pure air indoors. So, we can just replace the air filters and cleaning the entire system is just a waste of resources, right? Nope. 

On average, an air filter only stops 70% to 85% of contaminants from entering your home or business. The poor air filter can only do so much to protect you from air contamination, and about 15-30% will eventually end up in your air circulation. The finer particles can and will be accumulating in the recirculated air.

Air Filter: Unknown Fact 1

Another aspect many people might overlook is the fact that there might already be contaminants within the HVAC system! The air filter might not even have the chance to filter out the contaminants from your air circulation. Air filters are only placed between the system and outside air; it is not present within the systems themselves.

Air Filter: Unknown Fact 2

Besides the contaminants being able to slip past the air filter, there is an applicable scientific principle that causes failure of the air filter: Bernoulli’s Principle. It states that a region of fast-flowing fluid exerts lower pressure on its surroundings than a region of slow-flowing fluid. Simply put, the faster the flow, the lower the pressure.

How does that tie in with air filters?

Good question. As we all know, ducts come in many shapes and sizes to fit every part of the system. They have to be connected, and sometimes these airtight connections may degrade over time. If we apply Bernoulli’s principle to large and small ducts, smaller diameter ducts will channel faster airflow. ^{(This is called the Venturi effect, but I’m not here to bore you further)} Small ducts will thus have lower pressure compared to the outside air. And as we all know, regions of higher pressure will flow to regions of lower pressure. Air is pulled from the outside air along with all the contaminants into the circulation from the unsealed connections. Without this pressure difference, air contaminants will not flow as quickly through the unsealed duct connections. In essence, your air filter is great at its job, but nothing is perfect. 

Conclusion

While changing out the air filter regularly is an important part of maintaining your HVAC system, it does not mean it does not require regular cleaning as well. The contaminants that have passed your air filter will be stuck in the crevices of the air circulation system. Worse still, growths like mould and moss might find a comfy home in the air ducts. Air filters are ineffective in removing contaminants that are already downstream. This is very dangerous for you and your loved ones. 

Here at DUCTMATES, we are committed to bringing you our duct cleaning services to ensure your HVAC system remains in tiptop condition. We believe that cleaning out the insides of your air ducts should be done regularly just like changing out your air filters. You can contact us now by calling us at 1300 238 287 or fill up the enquiry form for quotations.