One of the most common sources of drafts and cold air in a home is a leaking attic entry hatch. They are often out of sight and out of mind but can lead to a lot of chilly nights and increased heating costs.
As with any drafty situation, the first thing to look for is a source of air leakage. When air can move from one area to another it takes heat with it. This is a good thing for hot air blowing out of a heating duct register but not ideal when that same heated air is moving in to the attic or outdoors.
From the thermal images and with visual inspection of this attic hatch it appears that the weatherstripping is inadequate. There is pretty good insulation over the center of the hatch but there is obvious air movement around the perimeter. Warm air from the house is leaking in to the attic which increases heating costs and decreases comfort in the home.
One of the cool tools that I use during inspections is a FLIR Thermal Imaging camera. This allows me to take measurements of temperature differentials of various surfaces and objects during an inspection. Useful for finding areas of air leakage and hidden insulation problems.
I took a picture of my sleeping dog Magoo this morning to show what the camera is capable of doing. The image on the left is the regular digital camera image while the picture on the left is a blended thermal image. Relative cool areas are darker, warmer areas are brighter. Magoo is working hard at sleeping and is significantly warmer than the floor he is laying on.
Thermal imaging works best when there is a large temperature differential between the inside and outside of the house. The images above show a front door from the inside on a cold morning. You can see a big temperature drop at the bottom of the sidelight window on the left and the bottom of the door. Looks like there is some air leakage on the bottom of the door - the weather stripping likely needs to be replaced.
Brian Jovag, owner of Jovag Home Inspection.