A standard 1″” throw-away furnace filter is between 5-10% particle efficient. This means that across the particle size spectrum, these filters will only trap about 5-10% of what passes through them. You can improve the efficiency of the filtration of your heating and/or cooling system by upgrading to either a media or electronic style filter. Their particle removal efficiencies are 60-65% and 90-95%, respectively and either is quite an improvement over standard 1″” filtration capabilities. By doing an upgrade like this, you will also cut down on maintenance costs on the system as dirty systems are the #1 cause for malfunction. This will also boost the efficiency of the system as the heat and cooling transfer coils will be able to operate with the least amount of resistance.