Out with the old in with the new, Get rid of your old air filters!
Changing your air filters will save you money in the long run. If an air filter becomes clogged it can potentially cause damage to your entire HVAC system. Regular maintenance will ensure the condition of your system stays in good shape. Also changing your filter allows for cleaner and all around healthier air. This is especially needed for children or those whom suffer from allergies.
Above is an example of a dirty/clogged air filter. Knowing when to change them out depends on a few things. For example, if there are pets in the home, what type of air filter that you have, and also the amount of people living in your home plays a part as well. Most of the time home owners will check them monthly just to be sure they are in good condition.