What size and type of filter do I need?
Filter sizes vary depending on the Brand and type of furnace that you have, however the most common sizes are 16x25x1 inch and 20x25x1 inch. Unless you have allergy concerns, we would probably recommend a standard filter because they are less restrictive. Most High Efficiency filters slow down airflow which can then increase your heating and cooling costs. Another good option, although a more expensive one, is an air filter with a low static pressure drop which normally costs between $700.00 and $3500.00.
It is important for all homeowners to remember that with any filter, they will only work when air is flowing through them! Regular maintenance of your furnace and replacement of the filter is important and if you purchase an expensive filter you should ensure that you run your fan continuously.