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How often should I change my air filter?

Filter replacement frequency varies from house to house and from place to place. 1” and 2” Clear the Air Furnace filters are designed to last up to 90 days before needing replacement.  Our larger sized filters such as the 4”, 5” or 6” should be replaced every 6 months. If you have pets, or if you live in a location that has more dust, pollen or similar air particles, you may need to change your filter more frequently. We recommend checking your filter monthly.
How do MERV ratings stack up against the 3M rating system?
Some filter manufacturers such as 3M use their own rating system, which is not approved as an industry standard. What do filter rating scores indicate?  The filter performance rating system can be used to compare one filter to another and describes a filter's ability to remove particles from the air.
The Filtrete Advanced Allergen , Filtrete™ Ultra Allergen , Filtrete Micro Allergen , and Filtrete Dust & Pollen are rated as MERV 12, MERV 11, MERV 11 and, MERV 8, respectively. 3M highlights the portion of the ASHRAE 52.2 test that focuses on sub-micron particles with its own performance rating. The filters above receive 1500 , 1250 , 1000 and 600 ratings, respectively.
Use the chart below to help you choose the correct filter to replace 3M Filtrete filters and save up to 66%.  Or download the full size performance and comparison chart here.


Why should I change my air filter?

After the recommended 3 or 6 months (depending on your filter size) the air filter becomes so dirty that it is no longer effective. In fact, it actually becomes harmful to your HVAC systems and your indoor air quality levels.
  1. A dirty furnace filter restricts the air flowinto your HVAC system which will ultimately cause system failure.
  2. A dirty furnace filter makes your system fan motor work harder. When this happens you will begin to consume more energy.
  3. A dirty furnace filter reduces the air quality in your home. Poor home air quality can aggravate allergies and asthma.
  4. A dirty furnace filter makes your heating system, air-conditioning system, and your ducts get dirty faster. This can lead to costly cleaning expenses or to a need to replace your units sooner than you expected.
  5. A dirty furnace filter increases your carbon footprint. Changing your filter reduces the amount of energy your home consumes. It’s an easy and inexpensive way to be environmentally responsible.


What kind of filter should I use?
You should use an air filter that offers the highest level of efficiency without damaging your HVAC system. Air filter efficiency is the measure of how well the filter does its job of filtering air before it enters the air handler. An air filter “cleans” the air by serving as a physical barrier to particles hanging in the air.  To measure the efficacy of a filter we use a MERV rating system.
What is a MERV rating?
The HVAC, (Heating, Ventilating and Air Conditioning) industry uses ASHRAE 52.2 testing, which assigns a Minimum Efficiency Reporting Value (MERV). A larger MERV number means better filtration. This is an industry standard rating system that allows you to compare filters made by different manufacturers. A MERV rating is a numerical value ranging from 1 (lowest efficiency) to 16 (highest efficiency) and tells the consumer how well the filter captures and holds dirt and dust of a specified size range.
What are my air filter dimensions?
Most standard filters print the dimensions on the filter frame. You can use those filter dimensions to select the appropriate size replacement filter. Unfortunately, some filters are not marked. In this case you will need to measure the dimensions of your existing filter.  Be aware that many filters may have actual dimensions that are not exact whole numbers—for example 17½” x 23¾” x 1”. If this is the case, you should round the fractional dimensions up to the nearest whole number. In the example, this would require a filter with nominal dimensions of 18” x 24” x 1”.
Why should I use a high efficiency air filter instead of the less expensive fiberglass filter?
Fiberglass filters need to be changed every 30 days effectively costing you more money.
A more efficient filter is more effective at removing particles from the air as it enters your HVAC system. Conversely, a less efficient filter allows more dirt and dust into your system. This dust and dirt will either land somewhere in the system or circulate back into the house. Dust and dirt on critical parts of your HVAC system will increase your fuel consumption and increase repair and maintenance bills. Dust and dirt circulated back into your home is just plain unhealthy.

Will I save money using a more efficient filter?
Very likely. This really depends on where you live and how you use your system. Experts have estimated that the average cost reduction derived from using a high efficiency filter is approximately 10%. This cost savings includes the reduction in fuel consumed by your HVAC system, and reduced repair and maintenance costs.
Will I have cleaner air in my home by using a more efficient air filter?
Absolutely. A more efficient air filter is designed to do a better job of cleaning the air as it enters your HVAC system. Clean air into the system means clean air is circulated back into your home.