In many houses and apartments, furnace filters serve several important purposes.  They are usually found in the central heating or furnace system, and are a clothe or paper filter.  All of the air that goes into the furnace to be heated must pass through this filter and some or all of the hair, dust and anything else that may be present are taken out by the filter.  You can search online in order to buy replacement furnace filters at a variety of online stores or find them at many home improvement and hard ware stores. 

The furnace filter is present for several reasons.  First, the filter helps keep dust, dirt and stuff that can burn out of your furnace.  This can help the furnace last longer, and may prevent a fire in your house.  The filter can also do a good job of removing dust from the air as it is circulated through the furnace, around your house, and then back through the furnace.  Without a filter in place, you would probably see much more dust in the air and settling onto all of your possessions.  In addition to being unsightly, this dust can also cause allergic reactions and make you sick in your own house!  If you have any pets, the filter can also remove animal dander which is another huge cause of allergies. 

It's critical to remember to change the filter in your furnace every couple of years.  In many cases, you must take the filter out, throw it away, and replace it with a new one. In other cases, you may be able to wash the dust out of the filter, let it dry and then put it back.  A filter that is full of dust may leave dust in the air, or may be putting a lot of strain on your furnace since it needs to work so much harder to pull air through the clogged filter.  When you throw away the filter, don't fall into the trap of forgetting to replace it with a new filter:  If your house is full of dust a few months later, this is probably the reason!

It's important to buy a filter that is the right size since air going around the filter may still have dust and other bad contents in it.  You can also find different kinds of filters.  A cheap filter may only remove larger pieces of dust and might leave some finer dust in the air.  Better quality filters may cost a bit more, but will do a better job of removing even the tiniest bits of dust from the air.  Some filters are especially meant for allergy suffers and can help make sure that breathing in your home is as pleasant as possible.  Some filters can help remove particular particles such as cigarette smoke from the air.  Others may be specially designed to remove pet hair and dander from the air in your house.

Furnace filters are an important component in making sure that you home is clean and not full of dust.  You can buy them online or find them for sale in your local stores.