There's a lot of money tied up in a home's heating and cooling system. Replacement costs can rise into the thousands of dollars, plus there are the heating and cooling bills to contend with. A well-maintained unit is one that will last a long time while doing so efficiently. When it comes to making sure maintenance is on track, the heating air conditioner filter is key.

In a typical home, a heating and air conditioner filter should be changed at least once a month. The need to change the filer may be higher if there is a lot of dust in the home or a particularly hairy animal. If you're unsure how often a filter needs to be changed, check it every few weeks.

The filter itself generally can be found over the air intake grill. This will be the large grill located either in a ceiling area or in a fairly inconspicuous wall. To change the filter, all that's required is a filter of like size. Open the grill by removing the screw and remove the old filter. Carefully place the new one in its place and close up and reseal the grill.

As you discard the old filter, this will generally serve as a very good lesson as to why it's so important to change a filter on a regular basis. On the new filter, you will notice a meshing system that's designed to let air flow freely into the heating and cooling system without taking dust and debris along with it. As the filter does its job, keeping debris out of the system, the meshing becomes blocked. If a total blockage is present, the cooling and heating system is not getting the proper amount of air required for it to run correctly. This translates into an inefficient running of the system, which means a greater heating and cooling expense for the home. It can also damage the system.

Also even with as well-designed as filters are, they still do allow some debris to get into the duct work. The more filthy the filter, the greater the chance for its failure. The dust and debris that makes it into the system will be returned to the air during the heating and cooling process along with bacteria and other undesirable agents.

To ensure a heating and cooling system runs properly, not only will regular changes of the filter be required, but also regular system maintenance. In general, a heating and cooling system should be inspected at least once every two years. Duct work will need to be fully cleaned about once every five to seven years and the coil and other components may require cleaning as well.

Changing the air filter, however, is the first step and one of the most important steps a person can take to ensure their heating and cooling system runs correctly and efficiently. Set a date each month to change the filter and also take advantage of the time to check batteries in smoke alarms. With a good eye toward maintenance, expensive heating and cooling systems should run at least their anticipated life span and perhaps even more.