There are many types of filter and variables. But here is the basic rule to start with.
- Flat panel 1″ thick. Change every 30 days. So 12 times a year.
- Pleated 1″ thick. Change every 90 days. So 4 times a year.
- Specialty air filters such as SpaceGard, AprilAire, Air Bear or Cub, Honeywell, General. These filters are 3″ to 5″ thick and should be changed once a year.
Variables that shorten a filters life
- Above normal household traffic
- If you have 1 of these variables check you filter at 1/2 it normal life and see how it looks. If you see build up and or darkened media, replace it. If not not check it again at 2/3 life.
- If you have 2 of these change it at half its normal life.
- If you have 3 of these, check it after 1/3 its life. If you see build up and or darkened media, replace it.
- Make notes (and leave them with your furnace papers) on filter conditions and filter change frequencies to help you next time.
Reasons to stay on top of this
- Dirty filters waste energy heating or cooling you home
- Dirty filters put a strain on your furnace or air conditioner, increasing furnace repair bills
- Dirty filters shorten the life of your furnace or air conditioner
- Always use a good filter
- Always remember to change your filter
- Remember changing a filter is a lot cheaper than not changing a filter, think furnace repair bills