One thing you should always consider is the best way and time to change the air filter of your central heating and air conditioning system unit. Even though you may have air filters that claim they last for a few months, do not believe that all the time and do not trust it! I feel it is better to be safe than sorry when it comes to changing the air filters of your central heating and air conditioning system unit. So I always make it a point to change the air filter of my central heating and air conditioning system unit once a month. To me and others this guarantees the fact that your air filter will not be overused and you will in no way be at risk of clogging the ductwork or overworking your central heating and air conditioning system to the point of it breaking down. If your central heating and air conditioning system was to break down because of this, it would have been a several hundred dollar repair bill you could have avoided by simply just changing the air filter of your central heating and air conditioning system unit once a month to be on the safe side of things. I started doing this a few years ago after my heating and cooling unit broke down as a result of not changing the air filter enough. This monthly change was suggested by my local heating and air conditioning specialist from the local heating and cooling company here in my local area that I use for all of my heating and air conditioning needs. It was a really great idea!