Thermography measures surface temperatures by using infrared video and still cameras. These tools see light that is in the heat spectrum. Images on the video or film record the temperature variations of the building's skin, ranging from white for warm regions to black for cooler areas. The resulting images help the auditor determine whether insulation is needed. They also serve as a quality control tool, to ensure that insulation has been installed correctly. For more on how infrared imaging works, check out our Energy Saver 101 infographic on home energy audits.
A thermographic inspection is either an interior or exterior survey. The energy auditor decides which method would give the best results under certain weather conditions. Interior scans are more common, because warm air escaping from a building does not always move through the walls in a straight line. Heat loss detected in one area of the outside wall might originate at some other location on the inside of the wall. Also, it is harder to detect temperature differences on the outside surface of the building during windy weather. Because of this difficulty, interior surveys are generally more accurate because they benefit from reduced air movement.
Thermographic scans are also commonly used with a blower door test running. The blower door helps exaggerate air leaking through defects in the building shell. Such air leaks appear as black streaks in the infrared camera's viewfinder.
Thermography uses specially designed infrared video or still cameras to make images (called thermograms) that show surface heat variations. This technology has a number of applications. Thermograms of electrical systems can detect abnormally hot electrical connections or components. Thermograms of mechanical systems can detect the heat created by excessive friction. Energy auditors use thermography as a tool to help detect heat losses and air leakage in building envelopes.
Infrared scanning allows energy auditors to check the effectiveness of insulation in a building's construction. The resulting thermograms help auditors determine whether a building needs insulation and where in the building it should go. Because wet insulation conducts heat faster than dry insulation, thermographic scans of roofs can often detect roof leaks.
In addition to using thermography during an energy assessment, you should have a scan done before purchasing a house; even new houses can have defects in their thermal envelopes. You may wish to include a clause in the contract requiring a thermographic scan of the house. A thermographic scan performed by a certified technician is usually accurate enough to use as documentation in court proceedings.
1) What is a home inspection and/or 'snagging'?
A home inspection/snagging is a professional consulting service that determines the present condition of the home’s major systems, based on a visual inspection of accessible features. 'Snagging' and home inspection refer to the same service, with the former being UK terminology and the latter used in North America. It focuses on the performance of the home, rather than cosmetic, code or design issues. Inspections are often performed during a real estate transaction but may be done anytime.
A home inspection is:
Absolutely. We encourage clients to attend. The inspection is a personalized course in home-ownership.
3) Do you tell us whether to buy the house?
No, we provide you with the knowledge to make an informed decision. We understand that the condition of the home is one of many critical pieces of the puzzle when buying a property.
4) How long does a home inspection take?
An average sized, straightforward home takes two hours plus or minus 30 minutes. Older, larger and more complex homes take longer.
The report writing process is typically about the same length of time as the inspection. Reports are sent to you the same day as the inspection.
Write something about yourself. No need to be fancy, just an overview.