What's Wrong with this Picture: Dusty Heater

ANSWER: Furnace Caked with Dust
It is extremely important to keep your furnace and furnace filters free of dust (as this label states). Dust can cause the unit to work less efficiently increasing your energy bills, but it can also recirculate into the air your family breathes and even cause a fire! Be sure to keep your unit clean and replace your filter monthly to avoid these issues. A big thanks to U.S. Inspect Inspector, Jerry Blodgett from our California team for sending us this picture.

Comments
Refirgerator Coils
This issue also applies to refrigerator coils, a very commonly overlooked item when it comes to house cleaning. Insurance companies will confirm this is a source of potential fires and is a safety hazard. If you haven't already, each time you do a home inspection, check out the underside of the refrigerator. I think you'll be surprised at how often the debris is several inches thick.