Is a high efficiency filter really worth it?
The filter in your home’s comfort system performs many functions. The filter was initially added to a heating and cooling system to stop a portion of the dust and dander from accumulating on the parts of the system to avoid system failure. The very first comfort system to use filters was forced air furnaces. In 1919, Alice Parker of Morristown, New Jersey invented the forced air furnace that provided central heating. It didn’t take the maintenance personnel long to figure out that dust and contaminants from the air were collecting on the internal parts of the system and that cleaning had to be performed very frequently. In 1920, the air conditioner was added to the home’s comfort system and the dust and contaminants would collect on the indoor evaporator causing the system to freeze up. As a result of this a filter was added to the air intake of the furnace to reduce the larges pieces of indoor air contaminants to allow the air conditioner to continue to operate without very frequent cleaning of the evaporator. So the disposable filters you typically find at the home improvement store are designed to protect your heating and cooling system.
In 1967, the oil embargo began which severely limited oil imports to the United States. The US quickly realized that reliance on energy exports was dangerous to the United States and the building codes were changed to create a more energy efficient home. As a result the “thermal envelope” of homes and buildings were required to be tighter and insulation was required. In the 1970’s it was discovered that the indoor air of homes and businesses were becoming dirtier than the outdoor air due to the lack of air exchange with outdoor air from the resulting thermal envelope sealing.
The US department of Energy (DOE) developed a “top secret” air filtration system to protect soldiers from radioactive particles on the battlefield. In the 1960’s the DOE coined this top-secret filter as a High Efficiency Particulate Air or HEPA filter. In the 1970s, this technology was no longer top secret and HEPA filters became popular in the United States to filter the contaminants out of the indoor air.
As technological advances were made in air filtration, more effective filters were developed such as electronic air cleaners, which ionize the incoming air with a small negative electric charge. The solids in the air that were ionized then cling to a metal wire that has a positive charge placed on it. These new advances plus advances in the effectiveness of the HEPA filtration have created air filters that have the ability to remove 99.97% of indoor air particles. These filters clean the indoor air so effectively they remove contaminants down to 0.3 microns in size. In comparison a human hair is 70 microns wide. These new filters have the ability to remove dust, mold spores, pollen and even bacteria.
To answer the original question – Is a high efficiency filter really worth it? – depends on your goals for a filter. If your goal is just to protect the heating and air conditioning equipment, then your standard disposable filter will work just fine. If your goal is to clean your home’s contaminated dirty indoor air, then the only way to accomplish this is through a high efficiency filter. How do you know if your homes air is dirty? The answer is simple, if you don’t have a high efficiency whole house filter, then your home’s air is very dirty. In fact, recent studies have shown indoor air is typically much more contaminated than outdoor air and can be making you sick.