Do you have your furnace air filter cleaned every few months? Did you even know that your furnace had an air filter until just now? It’s okay if you didn’t, because most people don’t. However, it’s very important that you have your air filter cleaned or replaced at least once for every three months you use it. Otherwise, you leave yourself open to one of the biggest problems a furnace can run into: short-cycling. Let’s take a look at how a clogged air filter can cause furnace short-cycling, and what that will do to your system.