Conduct—or hire someone to conduct—an infrared scan to measure thermal leaks in the building envelope to verify existing insulation levels in a building. These tests, also called thermographic scans, can be performed by energy auditors or other qualified technicians and offer a nonintrusive way to check insulation.
An infrared scanner can reveal if walls, or parts of them, lack sufficient insulation by measuring the surface temperature of the wall. Areas that lack sufficient insulation show up with different temperatures than areas with proper insulation because they conduct heat differently. Infrared scans will also reveal points in the building envelope where air is leaking through.
If insulation levels are found to be inadequate, an insulation contractor should be consulted to determine the best course of action for fixing the problem. Refer to the Purchasing Advisor topic “Building Shell: Insulation” for more on choosing insulation.
In some cases, minimum insulation levels will be dictated by local building codes. For areas without such stipulations, consider complying with the building envelope requirements in the latest version of ASHRAE (the American Society of Heating, Refrigerating, and Air-Conditioning Engineers) Standard 90.1, “Energy Standard for Buildings Except Low-Rise Residential Buildings.” This standard outlines minimum insulation levels based on climate zone. Installing higher levels of insulation may be cost-effective depending on the amount of the building's internal heat gains, its size, the construction of its envelope (including such things as the amount of glass it has), and the climate. However, to determine the cost-effectiveness of additional insulation would require conducting a building energy simulation.