Air filters are an essential component of any central HVAC system. The main purpose of the air filter is to keep dust and debris from getting drawn into the system. Some filters also help with indoor air quality by filtering out pollens and other allergens and airborne contaminants. Using the right type of filter is important for protecting your HVAC system and ensuring it can work effectively. When choosing which type of filter to use, the first thing you’ll need to decide is whether to use a reusable filter or a disposable filter. In this article, we’ll compare the two and also tell you everything else you need to know about choosing the right filter.
Understanding Air Filter Ratings
In truth, both reusable/washable air filters and disposable filters can work equally as well. There is really no difference between the two in terms of how they work or how effective they can be. The only time there would ever be a difference is if you were comparing a washable and a disposable filter that each had different efficiency ratings.
The majority of air filters on the market are rated in terms of efficiency or effectiveness using the Minimum Efficiency Reporting Value or MERV scale. The least efficient filters available have a rating of MERV 1, and these are generally only ever for things like window and portable air conditioners. The scale technically goes all the way up to MERV 20, but anything from MERV 16 and above is classified as a HEPA filter. These high MERV filters are generally only used for very specific applications like air purifiers and whole-home air filtration systems as well as in environments like labs and operating rooms that must be completely sterile.
For the standard air filter in a residential HVAC system, you’re usually limited to something in between MERV 6 and MERV 12 or 13. Anything under MERV 6 won’t be efficient enough to prevent dust and debris from getting sucked into the main part of the system, i.e. the furnace and the air handler where the blower and AC evaporator coil are located.
While you may think it is always best to use the most efficient filter with the highest MERV rating that’s available, this isn’t always the case. Higher efficiency filters are basically much denser, which allows them to trap many more particles and particles of a much smaller size. The issue is that the increased density also makes it much more difficult for air to flow through the filter. If you use a more efficient filter than your HVAC system can handle, it will greatly restrict the air flowing into the system. This results in it heating and cooling much more slowly and less effectively, leading to your home being less comfortable and your energy bills being higher. Using a filter that is too efficient will also increase the chances of your AC often freezing up. Even worse, restricted airflow will usually end up shortening the lifespan of the HVAC system.
Larger homes generally have more powerful HVAC systems that may be able to work just fine with a MERV 12 or 13 filter. For a smaller HVAC system, you may not be able to use anything above a MERV 8 or 10 filter without it creating the issues we just discussed. As such, it’s always a good idea to check with the HVAC technician when having your heating or AC maintained to make sure that you’re not using a more efficient filter than your system can handle.
Pros and Cons of Reusable and Disposable Air Filters
The fact that a reusable filter and a disposable filter with the same MERV rating can work equally as well means the choice ultimately comes down to a matter of price vs. convenience. A reusable filter will always cost you more upfront but less overall. Reusable filters typically cost anywhere from 40 to 160 CAD depending on the brand and how efficient they are. Disposable filters, on the other hand, usually cost around 10-25 CAD each. Considering that you should usually replace the filter in your HVAC system at least every three months, this means you’d likely end up spending a minimum of 40 to 80 CAD per year for disposable filters. Most reusable filters will last for at least five to 10 years or potentially even longer. That means you’ll end up spending far less in the long run if you opt for a reusable filter. You can save some money by buying a bulk pack of disposable filters, but they will still cost you more overall.
The main issue with using a reusable filter is that you need to make sure to take the time to fully clean it. If not, it will quickly clog up and create the same issues as using a filter that is far too efficient for your HVAC system. You also need to make sure that you let the filter fully dry before you put it back in place. If not, you run the risk of mold and mildew quickly starting to grow on it. This will not only make the air blowing out of your vents smell moldy and musty, but it also decreases the air quality in your home since your HVAC system will then circulate mold spores everywhere.
Another issue with reusable filters is you’ll want to leave your heating or air conditioning shut off while you’re washing the filter and waiting for it to dry. Running the system without a filter in place for even a short time is a bad idea since it will result in lots of dust and debris getting drawn inside. This is why if you do opt for a reusable filter, we’d definitely recommend buying two of them. That way you’ll always have a spare clean filter on hand so that you can just pop it in whenever the time comes to wash the first one. The alternatives are to risk running the system without a filter or shut the system off for 30 minutes at the very least and have your house start getting too hot or too cold.
The Importance of Regularly Washing or Replacing the Filter
Three months is the recommended interval for washing or replacing an HVAC air filter. However, there may often be times when the filter will need to be washed or replaced after just six to eight weeks. If you wait too long, the filter will always start to clog up and gradually decrease how much air can get drawn into the furnace or air handler. This will again lead to issues with decreased comfort, higher energy costs and increased wear and tear on your HVAC system.
The fact that how often you need to wash or replace your air filter can vary is why you should try to get in the habit of checking it at least once a month. This way, you can see when it is starting to get dirty and don’t risk continuing to run your HVAC system with a clogged filter.
There are also a few circumstances where you’ll almost always be better off replacing the filter more frequently. One is if you have pets in the home since pet hair can quickly clog a filter. Similarly, you may need to wash or replace the filter more often if you live in a dry climate due to the increased amount of dust in the air. The last situation is if you use a higher MERV filter. This is because the more efficient a filter is, the more particles it will trap and the quicker it will clog up.
If you have any questions about which type of air filter is best for your HVAC system, the technicians at Western Pacific Heating, Cooling & Airflow can advise you to ensure you’re using the right filter. We also offer the full range of residential and commercial heating, cooling and indoor air quality services for customers throughout the Vancouver area.
For more information or to schedule a service appointment, contact us today for AC maintenance.
