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Using thermal camera to find air leaks

Using thermal camera to find air leaks

Thermal imaging makes the otherwise invisible world of heat energy visible to your eyes.  Everything around you either emits or reflects heat energy. Teslong thermal cameras use color to show the relative temperature of objects in a picture called a thermograph. They are great tools because thermal imaging can see what your eyes can’t. You’ll see hot and cold spots where insulation is missing, identify where air is getting in or out of your house, and more. Keep reading to learn how to use a thermal camera to detect air leaks in home and how those leaks can be fixed.

What are thermal imaging cameras and how do they work?

While traditional visible-light cameras capture images of objects radiating light visible to the naked eye, an infrared camera captures infrared light, which the human eye cannot see. All objects radiate some form of heat energy, but some wavelengths within the electromagnetic spectrum are invisible, including infrared. Sensors in an infrared camera capture a particular range of invisible energy emission (700-1000 nm) and then express each heat value (or wavelength) through a set of corresponding colors. The resulting image is called a thermograph and is usually viewable on a LCD screen.

What are the best temperature differentials to look for?

When you are using an infrared camera to perform an energy audit on a house or other building it will work best when there is at least a 20 degree difference between the inside and outside of the building. This will work if it’s hot outside with the air conditioning on indoors or cold outside with a heater on indoors - both conditions provide adequate temperature contrast. 

Common culprits for thermal camera air leaks include doors, windows, exterior outlets, ducts, and connections to the outside such as cables or plumbing fixtures. Areas that might need additional insulation include attics, walls, floors, foundations, crawl spaces, and ducts. Older homes that have not been well maintained can usually benefit the most from air sealing and adding insulation. Air leaks and insulation gaps are also often created during renovations, when contractors are drilling holes or moving insulation around.

Easy projects to work on using your thermal camera

These easy projects use inexpensive equipment that can be found at your local hardware store. Many homeowners will feel comfortable performing these upgrades themselves.

  • Drafty Door: Use a thermal camera to detect air leaks, otherwise known as drafts. Drafts often occur under exterior doors. If you identify a draft or energy loss you can fix this by adding door sweeps to both regular and screen doors and check that existing door sweeps are in good condition. Use the thermal camera to verify the draft has been reduced or eliminated.
  • Leaky Windows: Even new windows can let air pass through around the edges. Add extra weather stripping along drafty spots, such as the underside of windows that open and close. If a window is drafty along the outside of the frame rather than along the window itself, caulk is needed rather than weather stripping.
  • Leaky Outlets: Exterior wall electrical outlets are often uninsulated. Block airflow by inserting socket sealers underneath outlet plate covers. For safety, you should always de-energize the circuits serving any outlets you will be working on.
  • Electronics on Standby: Here’s a good one to perform anytime you leave your house for a couple days or more. Many wall warts and other electronics can still use electricity when not being used. A thermal camera will show running electronics as brighter than their surroundings. Either unplug the device or install a smart power strip to stop electricity from flowing to unused devices.

Medium difficulty projects to work on using your thermal camera

Using a thermal camera for air leaks is a great way to ensure that your home is energy efficient and not wasting any energy and ultimately money. Medium difficulty projects use equipment that typically must be bought at a store or ordered online. Many homeowners will feel comfortable performing these upgrades themselves.

  • Drafty Fireplace: Fireplaces and wood burning stoves are classic areas for heat loss since chimneys need to exhaust smoke while fires are burning. During the summer months when your fireplace is not in use you can temporarily block air flow with a chimney balloon or fireplace plug.
  • Uninsulated Attic Door: Even well-insulated attics can be missing one key component – an insulated attic door. A variety of attic door covers are available depending on the size and type of your door.

Long term projects to work on using your thermal camera

Long-term projects are more difficult to DIY and are often performed by a contractor that specializes in energy auditing or insulation. Many HVAC contractors now use a thermal image camera to find air leaks because it gets the job done faster.  Many homeowners will not feel comfortable performing this type of renovation themselves.

  • Inadequate Insulation: Missing pockets of insulation inside of walls can be seen by infrared cameras. Sometimes insulation needs to be added everywhere – i.e. the R-value was simply too low – your contractor will know what your local building code requires. More commonly, insulation gets moved when installing ceiling fixtures such as recessed lighting – these insulation gaps can be quickly identified with a thermal camera and can be fixed by a qualified technician.
  • Uninsulated Foundation: Home foundations are often uninsulated, and as such it is common to find air leaks between the foundation and the bottom of the house. Consult with a contractor on the best way to fix this type of a problem.
  • Uninsulated Crawlspace: Many homes have crawl spaces under one area of the house where an addition has been added. Thermal cameras will show this as a thermal shadow on the floor that mimics the crawspace below it. These situations usually also require a contractor consultation to fix properly.
  • Leaky Duct: The ducts that provide conditioned air throughout your house can also be uninsulated and leaky. If your ductwork is exposed, you can insulate and seal it yourself, but ducts located under the floor will likely need to be worked on by a professional HVAC technician.


These easily fixable problems may be costing you an average of $200 to $400 per year according to the U.S. Department of Energy. Getting a thermal camera to quickly identify where energy leaks are happening as well as verify that any work done is actually stopping the leak and will quickly save you money. Teslong makes a range of thermal cameras that can be used for identifying air leaks, energy loss, and other thermal problems when you are performing a house inspection. Thermal cameras are also great for finding people or animals in the woods, quickly locating water leaks, checking for properly functioning plumbing, identifying overheating electrical components, and many other applications.


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