Do you know that having pets in the house will greatly reduce the longevity of your furnace filters? Pet hair and dander can “fill up” your filter much quicker than many realize. Pets can reduce the amount of time between furnace filter changes by quite a bit.
For filters 1″-2″ you need to replace the filter every two months.
For a 4″ filter, you need to replace the filter every four months.
For 5+” filters, you need to change them every six months.
These filter replacement timeliness are for households with one pet. If you have more pets, it might need to be even more frequent.
You can always check the filter. If it looks discolored or has a build-up of dust it should be replaced.
There are also special filters designed specifically for households with pets you can also consider but they do often cost more money.