So now that we got the filter change out of the way, we can talk about the various filtering options. The majority of homes we have in San Jose South Bay Area are fitted to use a standard 1" filter. They can be found in either the return filter grille or inside the furnace. The 1" filter also comes in a variety of flavors. There are flat filters that need to be changed on a monthly basis. They offer the minimum protection you need but they have the least air resistance. The pleated filter offers a bit higher effectiveness because of its higher surface area per square foot. Filter manufacturer also makes electro-statically charged version of the pleated filter that does a more effective job of holding the dust particles. Most of the sizes for 1" filters can be found at home improvement stores like Home Depot or Lowes.
If members of your family have allergy problems, you may want to consider some higher end filtration options. There are two main types, passive and active. Both require professional integration into your existing system. They are best installed when you are changing out your furnace or AC system. We will talk about them next time.