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Efficiency Ratings for Furnace Filters

Furnace filters

The air quality in your home is not just important to you, but also to the overall health of your family. With pollutants spread all over the environment nowadays, checking the efficiency of your air filter is critical in determining whether it is up to the task or it is letting in unwanted particles in your indoor space. the quality of your filter also affects the operational efficiency of your furnace. Not all air filters are the same and for this reason, some homeowners find it difficult to determine their efficiency.

When looking to enhance your filter efficiency, there are specific ratings that you must look at. Some of these include:

Minimum Efficiency Reporting Value

This is abbreviated as MERV and refers to an industry standard used in evaluating the efficiency of air filters. The MERV scale ranges from 1 to 16 with 1 being the lowest rated filter while 16 the highest. That said, MERV should not be taken as the sole deciding factor when purchasing a new filter. There are others to be considered as well.

Pressure Drop

This metric or filter rating tells you something about how your furnace filter will impact the air flow of your system. Air filters that have higher pressure drops make your system work harder so as to force air through them. The result of this is increased energy expenditure which as a consequence raises the needle on your energy bills. When looking for filters, pick those with low pressure drop rating so as to maximize the air flow.


This is simply a measure of how well your air filter performs in blocking harmful particles and allergens such as pollen, dust, and mold. More efficient air filters capture the particles even the smaller ones which means they won’t circulate in your home. On the other hand, inefficient filters will let in the smaller particles which in turn gets blown away and circulated inside your home. This may lead to health-related problems and the aggravation of asthma.

Initial Efficiency

This rating shows the performance of a filter when it is new. Even though this is indicated in some filters, it doesn’t give you much insight because your filter won’t be new forever. As a matter of fact, it will only be new for a shorter duration. However, it gives you a measure of what you are getting in exchange for your money.

Sustained Efficiency

This is a better measure of the performance of furnace filters compared to initial efficiency. It tells you how well your filter will maintain its efficiency for the duration of its life. Of course, this efficiency is affected by its maintenance and the magnitude of particles flying around in the place of its installation.

Even with the efficiencies and ratings discussed above, air filters need replacement at least once in a span of 1 to 3 months. Failure to do so will make their efficiency drop to the detriment of you and your family. Furnace filters can be easily obtained and replaced, but if you cannot do either or both, get a professional to help you.