How often to change filters on Heating Furnace and Air Conditioning systems

“How often should we change our filters on the heating and air conditioning system?” The answer is not so simple.  Thing is every house and every situation is different.  Sometimes it must be changed every 2-3 weeks and sometimes one can go 4 months with out changing the filter once.

Here is how you can determine this for yourself.  This will require some testing and keeping track on your part though.  But let’s start from beginning, why does one need air filters.  First and foremost filters clean the air you breathe.  So a clean filter benefits your health greatly.  Second, a dirty filter gets clogged and become not as porous (that may not be the proper term, but I’ll stick with the term).  An HVAC system is designed to move a certain minimum amount of air per given period of time.  Perhaps for heating furnace that is not as critical as it is for air conditioning.  An air conditioning air handler coil contains refrigerant that boils at a very low temperature (r-22 -41.62°F and R410A  -55.3°F) So when it enters the coil it must be warmed up with a certain amount of airflow to prevent it from freezing.  By having a dirty/ clogged filter airflow is reduced, which gives it a “frozen coil” effect, which if unchecked can create severe problems.

So, that being said the best thing to do is keep the filters clean and changed as often as needed.  How often?  We’ll get to that in a sec.  Being to a lot of houses I can tell you that the situation is different per house.  Kids and pets tend to create dust.  Bigger houses will tend to have more dust.  How clean is the house?  How much foot traffic? and etc.

Now that you understand why here’s the how.  Check your system’s filter every week from new change.  Count how many weeks it took to get to lightly dirty. Do not wait until its opaque.  There are different types of filters.  The pleated ones will trap more and smaller dust particles, but will get clogged much quicker.  The cheaper “Brillo” looking ones are more forgiving but will let more dust through.  They will each get dirty at different rates. Remember that a consistent filter change will enhance the performance and prolong the life of your HVAC system.

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