Air Seal Assessment
Pressure Boundary Investigation
In order for insulation to be most effective, it should be installed with no gaps, voids or compressions. Insulation performance is significantly reduced when subjected to wind and air intrusion. As a result, a thorough investigation of all the possible thermal bypasses around the envelope of the building must be a part of a good energy assessment so they can be properly addressed. A determination should be made as to whether or not there is a proper air barrier in-line with the insulation that is installed. The air barrier should be contiguous and continuous over the entire thermal boundary and it should be perfectly aligned with the insulation.
Check Out How to Target a Thermal Bypass with Blocking and Sealing
Example 1 - Open Top Plates
Top Plate Air Gaps - Most Attics Have this Problem
With open holes and cracks and crevices around drywall, wrongly drilled holes that were never filled in and other bypasses associated with the top plates, warm and cold air take advantage of those gaps and go in and out of them wreaking havoc on your comfort and your energy bills. One way to check this is to have a thermal image taken on a cold or hot day. Easier and less expensive is to take a trip up to the attic and take a look.
Interior Upstairs Hallway Location of Top Plates
Example 2 - Recessed Lights
The Issue-Recessed Lights are Gateways to the Attic
Older and less expensive recessed light fixtures (inserted in photo for closer look) have slots and holes for the heat generated by the lightbulb to escape so that it lessens any fire hazard. The problem is that when recessed lights are in any way connected to the attic as seen here, it creates a gateway or connection to the attic. Although the attic is covered by the roof, it is outside of the home.
Building Performance Institute
BGE Approved Energy Contractor
Learn More - Energy Audit Basics