It was Friday, and we were working residential HVAC, checking air circulation violations. I'm Joe Blow, heating and cooling cop. My partner, Frank Nit-picky, and I were on our way to San Jose on a code blue. Needless cold rooms, not a pretty picture. "Open up, HVAC Police! Understand you've suddenly got chilly rooms, cold feet, shivers and shakes -- sound familiar, sir? Doesn't have to be that way. Sounds like you've got a blocked cold-air return somewhere in your house. Time for a thorough air circulation investigation. Forced air furnaces blow heat through ducts and once cooled, the air returns through vents to the furnace to be reheated and sent out again -- got the picture? But if air return vents are blocked, your heat is a no-go. Has any furniture been moved? Is a closed door preventing normal air flow? Bad circulation reduces comfort and wastes money. Find what's blocking your return and it's solved." That's the facts sir, have a nice day. And that's the On The House tip for today.