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Section 5: A Cleaner Home with a Clean Air Filter
A clean air filter not only benefits your HVAC system and your health but also keeps your home cleaner. When dust and other particles are trapped in the filter, they don't circulate through your HVAC system and settle on surfaces in your home.
A filter with a MERV rating of between 1-6 can remove particles anywhere between 0.3 to 10 microns with an effectiveness of 20%. It can remove small particles such as dust mites, spray paint dust, carpet fibers, and pollen.
If you are looking for a filter that can efficiently capture large particles, then MERV 13 is a good option. If you are looking for a filter that can efficiently capture smaller particles, then HEPA may be a better option.
In most cases, a MERV 11 air filter isn't too high for residential use. Generally speaking, anything under a MERV 13 air filter should provide very efficient air purification in a home without impacting airflow.
The MERV 11 air filter is the wrong choice for people who do not own pets and do not have any breathing trouble; this is because it can lead to restricted airflow. Air filters with higher ratings can also have negative effects on HVAC components.
High-MERV filters increase the static pressure of your system, and if the ductwork is already marginal, this can cause the airflow to drop to a level where the temperature exceeds the furnace's limit.
HEPA Air Filters
A HEPA filter is a type of pleated mechanical air filter and is extremely efficient and effective. According to the Environmental Protection Agency can theoretically remove 99.97% of dust, pollen, mold, bacteria, and any airborne particles with a size of 0.3 microns.
The primary drawback of high MERV filters is that the pressure drop across them is too high, which can lead to reduced airflow and increased energy consumption in HVAC systems. This resistance may strain mechanical components over time, potentially causing failure.
The abbreviation stands for Minimum Effective Reporting Value. In other words, it's a measurement showing how small the holes are in the filter. The higher the MERV number, the smaller the holes, and the less that can pass through. Ultimately, this is what makes MERV 14 filters not a good choice for home use.
There are thousands of portable air purifiers that can help, but the best room air filter for dust is a HEPA filter. Unlike home air filters for an HVAC system, highly efficient HEPA air filters work very well in a standalone air purifier. A HEPA air filter traps 99.97% of particles in the air.
You may not need a MERV 11 filter or higher unless you have specific air quality issues or allergies. For the average household, a MERV 8 air filter can be good enough. You'll want to think about factors like how often you want to change your filters and what type of material do you want filtered out of your air.
Suitable for Most Homes: MERV 8 filters are effective at capturing larger particles like dust, pollen, and pet dander. For many homes, especially those without specific indoor air quality concerns, MERV 8 filters strike a good balance between filtration and airflow.
You need an air purifier with a HEPA filter. HEPA filters capture 99.97% of dust, pollen, mould, and traffic pollution particles.
If you notice a lot of dust in your house, it's likely due to a combination of factors affecting air quality and ventilation. Dust particles from outside can enter through open windows or doors, while indoor sources like pet dander, dead skin cells, and fibers from textiles contribute to the buildup.
Part of the reason that HEPA filters are so rarely used in HVAC systems is that they are extremely restrictive in terms of airflow. This means that the system needs to be extremely powerful and use additional fans in order to properly draw air through the HEPA filter and circulate it throughout the room or building.
MERV 8 filters capture basic particles like dust, pollen, and pet dander and are adequate for most households. Higher ratings, such as MERV 11 to 13, offer enhanced filtration, capturing smaller particles like mold spores and smoke, which is beneficial for those with allergies.
It's also difficult for many existing HVAC (Heating, Ventilation, and Air Conditioning) systems to adopt a MERV 13 due to the increased load on the fan from the finer filter media, which can actually cause more harm than good as well as reducing airflow if your system isn't designed to handle that type of filter.
Designed with exclusive Filtrete™ 3-in-1 technology, including a high MPR 1500 and MERV 12 rating, your AC filter will help pull and capture countless microparticles – such as pet dander, smoke, bacteria and up to 54% of virus airborne particles (1) – while letting cleaner air flow through.
Pleated filters can restrict airflow slightly more than non-pleated ones, but they balance filtration and airflow. Choosing the right MERV rating (between 8 and 13) ensures your system gets proper airflow while still effectively filtering the air.
One of the main disadvantages of air purifiers with HEPA filters is the need to replace these filters regularly to maintain their effectiveness. A HEPA filter should be changed every 6 to 12 months, depending on its use and the environment in which it is used.
Filters within a MERV rating of 17-20 are almost never necessary in a residential home. A MERV rating of 13-16 is considered hospital level air quality, so it is unlikely your home needs any more than that.
The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) suggests purchasing a filter with a MERV rating of 6 or greater for your home.
In some cases, using an air filter that is too restrictive for your system may cause low air flow problems as well. MERV 13 is the highest MERV value safe for residential furnaces; the higher ratings are used primarily in commercial units.