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Replacing the air filter is the most important part of maintaining your HVAC system and ensuring it continues heating and cooling effectively. If your furnace or AC runs daily, you never want to go for more than three months without replacing the filter. In the much hotter or colder times of the year when your HVAC system runs for more hours a day, you’re better off replacing the filter every month or two. You’ll also want to replace the filter more frequently if you live in a drier, dustier climate. This is also the case if you have indoor pets since all of the dust or pet hair and dander will cause the filter to clog up more quickly.
It’s also important that you choose the right filter for your HVAC system and your home. Air filters primarily serve to keep dust and airborne debris from clogging up or damaging your HVAC system. They can also have an impact on the air quality in your home. In this article, we’ll explain air filter ratings, what to look for when choosing an air filter and everything else you need to know.
Air Filter Ratings Explained
The efficiency of an air filter is determined by what percentage of airborne particles it can trap or filter out. Lower-rated filters are efficient at filtering out a majority of larger airborne particles like dust, lint and hair. But most smaller particles will easily pass through them and not get filtered out of the air. This is what sets higher-rated filters apart, as they are much more efficient at trapping extremely small particles.
Most manufacturers use the MERV (Minimum Efficiency Reporting Value) scale to rate how efficient their air filters are. MERV ratings are determined by measuring the percentage of various-sized particles that the filter can effectively trap.
The MERV scale technically goes from 1 to 20, with MERV 1 being the least efficient and MERV 20 being the most efficient. Almost all standard filters designed to be used in residential heating and cooling systems range between MERV 6 and MERV 12 or 13. Any filter that is rated at MERV 16 or above is considered a true HEPA filter.
Some manufacturers and retailers like 3M and The Home Depot instead have their own proprietary rating scales. However, most also label all of their residential air filters as “Good,” “Better” and “Best.” In this case, “Good” usually corresponds to around MERV 8, “Better” is typically around MERV 10 and “Best” is around MERV 12 or 13.
When choosing a standard filter for your home’s HVAC system, it is important that you never go with anything under MERV 7 or 8 or above MERV 12 or 13. The reason is that higher-efficiency filters are far more restrictive in terms of how much air can flow through them. If the filter is too efficient, it will make your heating and air conditioning much less effective and cause your energy bills to greatly increase.
Using too efficient of a filter will also force the HVAC blower to work much harder. This can lead to it suffering more issues like overheating or wearing out much more quickly. If you choose a less efficient filter, it will lead to lots more dust and debris getting drawn inside your HVAC system. This can potentially decrease its performance or damage its components.
How To Know Which Air Filter Is the Best Choice
The choice of which air filter you want to use in your HVAC system largely depends on how concerned you are about the air quality in your home. It also depends on how much you’re willing to spend. If your main concern is keeping dust out so that your HVAC system works effectively without as many issues, you’re fine to go with a cheaper, less efficient filter.
If anyone in your home suffers from allergies or a respiratory illness like asthma or COPD, you’ll definitely want to opt for a higher-efficiency MERV 10 to 12 filter instead. While filters with a higher MERV rating cost more, they will be far more effective at removing allergens and irritants like pollen, pet dander, dust mites, and spores.
Another thing to consider is whether you want to use a disposable filter or a washable, reusable filter. Disposable filters are more convenient and cost less upfront, but will have a higher long-term cost. Washable filters, on the other hand, will typically cost at least $50 to $100 or more upfront, but will usually last for five years or so. Consider that you should always replace or wash your air filter every one to three months. This means that you could go through 20 to 60 disposable filters in the same time as you would one washable filter. However, a washable filter will require more work since you’ll need to frequently clean, rinse and dry it instead of just pulling an old disposable filter out and replacing it.
HVAC Air Filters vs. Whole-Home Filtration Systems
If you suffer from allergies or asthma or are more concerned about the indoor air quality in your home, you do have another option to install. This is using a media filter, electronic air cleaner or whole-home air filtration system. Most media filters and electronic air cleaners range from MERV 13 to 15. Many whole-home filtration systems utilize HEPA filters that can capture more than 99% of all airborne particles, pollutants and contaminants.
A media filter is typically installed in place of a traditional air filter and is basically just a thicker, more efficient physical filter. This means that you’ll need to make sure that your HVAC blower is powerful enough to draw sufficient air through it to keep your HVAC system working effectively.
With an electronic air cleaner, you don’t have to worry about any issues with it restricting the airflow in your HVAC system. This is because these units don’t use physical filters or barriers to trap particles and, instead, work by giving the particles an electric charge. This type of unit produces an electromagnetic field that charges any airborne particles as they enter it. At the opposite end of the unit where the air flows out are special plates that are oppositely charged. Just like a magnet, the charged particles stick to the oppositely charged plates so that they’re removed from the air as it passes through the unit. Electronic air cleaners are typically much more efficient than media filters since they will trap even microscopic particles, gases and exhaust fumes that would otherwise pass through a physical filter.
Whole-home HEPA filtration systems always have to be installed in a bypass duct that is attached to the main supply or return air duct. This type of system uses an internal fan that pulls some of the air out of the duct and through the filter. This is important for preventing the filter from restricting how much air can flow through the system.
Contact the Professionals
If you have any questions about the air filter in your home or need any heating, cooling or indoor air quality service in the Sacramento area, Atticman Heating and Air Conditioning, Insulation is here to help. We specialize in the full range of HVAC services and can help if you need any repair, maintenance or installation services. We are also there if you are looking to upgrade your home with a filtration system or other indoor air quality unit. For more information or to schedule a service call or consultation, contact us today.
