Heating and cooling systems move heat around, which makes them a natural fit for thermal imaging. A camera can show problems you would otherwise find only by cutting into ducts or taking apart equipment.
What to check
- Supply and return registers. Compare temperatures across rooms to find ones that are not getting enough conditioned air.
- Ducts. Hot or cold streaks along exposed ductwork and joints can point to leaks and missing insulation.
- Coils and heat exchangers. Uneven patterns on a coil can suggest blockage or poor airflow.
- Refrigerant lines. Unexpected temperature changes along a line can hint at a restriction.
- Motors, bearings and electrical connections. Running hotter than normal is an early warning sign.
- Radiant heating. Floor and wall loops show clearly, so you can trace layouts and spot cold sections.
Temperature split
A common check is the difference between air entering and leaving a cooling coil. Many references cite a split of roughly 15 to 20°F, but the right figure depends on the system and conditions, so follow the manufacturer's specification. A thermal camera shows surface temperatures, so use a proper probe thermometer for airflow readings.
Tips
- Let the system run long enough to stabilize before scanning.
- Take a thermal image and a visible photo of every finding.
- Do not scan through glass or shiny panels. Reflections give false readings.
The right tool
A camera with a wide enough temperature range and 256×192 resolution suits most HVAC work. A handheld is convenient in a van or on a roof, but a phone attachment works too. Compare them in handheld vs phone cameras, and see our buyer's guide.