When the temperature dips below 0 degrees, as it did last night and early this morning when my weather station indicated a frosty -15 degrees, I often find myself reaching for my Black & Decker thermal leak detector. It uses infrared sensors to measure surface temperatures. Press the button, aim and the LCD display provides the temperature at the target spot, plus projects a blue light for problem areas.
It's much cheaper than paying a consultant to do an energy audit of your house and -- if you're like me -- you will be surprised at the unexpected spots where trouble lurks. Last night, I found a spot inside a closet (with poor insulation between it and the mudroom) that was a whopper! Didn't take long to fix that source of heat loss.