Honey and I got up this morning to find our furnace not working and our house a freezing 55 degrees (it was below zero outside). At 5am he cycled the furnace off and then on again before leaving for work. Nothing happened. At 8am I repeated the process. The fan came on, pushed out cold air and then turned off. Still freezing. Honey called the repair guys. I called into work for the morning in order to sit around and wait for the repair guys.
Repair guy showed up and examined the furnace. About 15 minutes into his visit, and just before he busted out his screwdriver, I just happened to mention the air filter and how it hadn’t been changed in months. So he opened the door, pulled out the air filter and found it overflowing with dust, dirt, “allergens” and the shedded hair of three cats and a dog.

DUHHHHHHHHHHH!

So it cost us $40 to pay some guy to change our air filter (which we already had!).

Again, I say DUHHHHHHHHH!