How do I check for insulation voids using a thermal camera in New Brunswick? | Insulation IQ?

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New Brunswick Insulation · Accepted Answer

Thermal imaging is one of the most powerful diagnostic tools available for assessing insulation performance, and New Brunswick's climate actually makes it an especially effective technique. The large temperature difference between indoors and outdoors during a NB winter creates strong thermal contrast that makes insulation voids easy to identify — provided the inspection is done under the right conditions and interpreted correctly.

How thermal imaging works for insulation inspection is straightforward in principle. An infrared camera does not see through walls. What it captures is the surface temperature of materials — the temperature of drywall, plaster, sheathing, or concrete as seen from the camera's position. When insulation is missing from a wall cavity, the drywall surface in that cavity cools down faster and to a lower temperature than the drywall over an insulated cavity beside it. On a cold New Brunswick day with the furnace running, an insulation void shows up on a thermal image as a distinctly cooler zone — blue or purple on the standard colour scale — against the warmer background of the insulated wall surface.

The most important condition for accurate thermal imaging is a sufficient delta-T (temperature difference) between inside and outside. Professional guidelines recommend a minimum of 10°C difference, but New Brunswick's climate regularly provides 20–30°C or more during January and February, which makes mid-winter the optimal time for this work in Moncton, Fredericton, Saint John, or anywhere else in the province. An inspection done on a mild autumn day with a 5°C difference will miss many voids that would be clearly visible in January.

Blower door depressurization greatly enhances the effectiveness of thermal imaging. By using a fan mounted in a door or window to depressurize the home to approximately 50 pascals below outside air pressure, the inspector forces outside air to move through any leakage paths at an accelerated rate. This dramatically amplifies the thermal signature of both air leakage and insulation voids, making small gaps visible that would be imperceptible under natural conditions. Every professional energy audit in New Brunswick that uses thermal imaging should be done in conjunction with a blower door test for this reason.

If you are doing a preliminary self-assessment with a consumer-grade thermal camera (cameras now attach to smartphones for $200–$400, or can be rented from some tool rental shops), follow these practical steps. First, condition the house: run the heating system normally for several hours before inspection so the interior temperature differential has stabilized. Aim to inspect on a day when outdoor temperatures are below -10°C. Walk along each exterior wall, scan from floor to ceiling, and look for patches that are visibly cooler than the surrounding wall surface. Pay particular attention to corners, areas around windows and doors, the band between the first and second floor, and anywhere pipes or wires penetrate from outside.

What you are likely to find in a typical older NB home includes: cold patches at the base of walls where rim joist insulation is missing or has fallen out, cool vertical bands corresponding to individual stud cavities where batts were never installed or have sagged, cold spots around electrical outlets and switch boxes on exterior walls (these are penetrations through the air barrier), and broad cold zones in attic access hatches that were never insulated. In attached garages, the wall and ceiling separating the garage from the living space is frequently under-insulated and will show up clearly.

Interpreting the images correctly requires some caution. Thermal bridges — areas where structural framing (studs, headers, joists) conducts heat more rapidly than the insulated cavities — appear cooler on thermal images even when insulation is correctly installed. Studs visible as regular vertical cool lines in a wall are normal and expected. What you are looking for is irregular cool patches, large cold zones, or areas where the pattern suggests an entire bay is uninsulated rather than just a stud.

For attic inspections, thermal imaging is best done from inside the attic looking down at the attic floor, or from the living space below looking up at the ceiling. Missing or thin insulation at the attic floor level — the most critical insulation location in a Climate Zone 6 home — shows up as warm patches in the ceiling seen from the attic in winter, as heat from below radiates through the thin spots. The NB Building Code requires effective R-31 or better in attic assemblies for new construction; many existing NB homes have R-12 to R-20, and thermal imaging can show which areas are worst.

For a formal audit that qualifies for the Canada Greener Homes Grant (up to $5,600 for insulation and air sealing) or NB Power's Home Energy Efficiency rebates, the thermal imaging must be conducted by a certified EnerGuide auditor. Audit fees in New

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