The pictures below will show the advantages of Spray Foam Insulation. These pictures were taken with an infrared camera. Pay attention to the temperature scale to the right of the picture. You will notice that the lighter the color, the hotter the temperature. These pictures were taken at night with an ambient (outside) temperature of 30 deg. F. Both pictures were taken on the same night, just minutes apart. As you can see, the hottest temperatures are coming from under the eaves, tops of the windows and upstairs wall of this house. You will notice that the temperature scale I mentioned shows that the white areas are at or above 50.1 deg. F. This means that this house is continuously loosing 20.1 deg. F of heat. This house is insulated with traditional fiberglass insulation.
This house is insulated with Spray Foam Insulation and as you can see, it is not loosing any heat through the eaves, windows or walls. You should also notice the temperature scale to the right of the picture. The hottest point on this picture is 37.8 degrees and it is coming from the front porch light. But, this home owner elected not to spray the crawl space with foam insulation and the next picture will show the results.
Even though you will notice that the temperature scale is lower for the heat loss on this house, at a mere 6.8 deg. F, there is still heat loss. After seeing this picture, the homeowner decided to spend the money to insulate his crawl space. This house should now be very efficient. The white area over the front door is from the porch light being turned on.