Air leakage in forced air duct systems is now recognized as a major source of energy waste in both new and existing houses. Studies indicate ductwork air leakage can account for as much as 25% of total house energy loss and can prevent heating and cooling systems from operating properly, resulting in uneven heating and cooling of rooms.
Air leakage into wall cavities and ceilings, because of poorly sealed or installed ductwork register boots, ranks at the top of the list, due to the volume of air which leaks during operation of the heating and cooling systems. These leaks can heat or cool entire wall cavities and is the largest contributor to condensation. Most if not all of these register boots are un-insulated or sealed at the drywall/boot junction.
This photo show extensive air leakage between ceiling and insulation in the attic space in this one year old home.
Air leaks can also cause condensation resulting in mold/mildew growth.
Condensation may be identified through basic visual inspection if it has lead to obvious defects, such as staining or mold growth. However, by the time visible evidence has presented itself, significant damage may have already been done. In many cases, condensation may have been developing for awhile before obvious signs become apparent.
By employing thermal imaging and a moisture meter, inspectors can locate condensation issues before they become large problems and lead to serious damage. While an infrared camera does not specifically detect moisture itself, it does detect differences in temperature. When a material becomes wet and saturated with water, its temperature will be cooler than the surrounding areas because water takes longer to warm up than, wood or drywall. In order to verify what the IR camera is seeing, I use a moisture meter to verify the present of moisture.
The left photo shows possible mold/mildew growth at the ceiling/wall junction in garage. The right photo shows ductwork air leakage (bright colors, center of photo). The infrared scan was performed with the HVAC system in the heating mode. Since the garage is not a conditioned space (heated or cooled), condensation forms where air leakage is present, allowing mold/mildew to grow.
Photo shows mold growth due to ductwork air leakage and excessive condensation.
No matter whether your home is one year old or fifty years old, you can benefit from an infrared scan of your home’s ductwork.
Rich Roshak is a Level II Certified Thermographer, Licensed building inspector and Licensed Home inspector and has been serving home and building owners in New Jersey for 17 years