Infrared (IR) Thermography (also known as an "infrared thermal scan" or "thermal imaging") is a useful tool to help find anomalies that may otherwise remain hidden in walls, floors and ceilings. Infrared energy is heat energy. Since all objects on Earth are above absolute zero (-273° C), they emit heat energy to varying degrees, even ice cubes! A properly trained infrared thermographer can interpret an infrared image and determine if a roof or plumbing leak exists, if there is missing wall or ceiling insulation, if an electrical component is reaching critical temperature levels, or if no major issues exist at all. The purpose of most thermography work, as performed by home inspectors, relates to looking for anomalies within a building. An anomaly is a situation that is otherwise not to be expected under normal conditions.
Matthew Steger, inspector/owner of WIN Home Inspection has been trained and certified by the Infrared Training Center (ITC) to perform Infrared Thermography; he is a Certified Level 1 Infrared Thermographer. Examples with photos of just some of the issues that we have found by using infrared technology are shown below under "Some Infrared Thermography Applications".
Heat is energy and is continually moving to an object or surface with less heat. Once two nearby objects are at the exact same temperature, there will be no further heat transfer between these two objects. Also, there is no such thing as 'cold'. Cold is just a relative term meaning a lower amount of heat energy compared to a warmer object. For infrared technology to work properly, objects must be at different temperatures. If you were to walk into a room where everything was the same temperature, IR technology wouldn't be of much use since the infrared camera would essentially just see one temperature (all items with the same amount of heat). Luckily, in homes and other buildings there are various components such as walls, ceilings, plumbing, electrical wiring, heating/cooling equipment, and insulation. Each of these systems and components relate with heat energy in some way and how well these systems deal with heat energy is where infrared technology comes in.
Moisture within a building can damage building components and can lead to rot and/or mold. Quick moisture detection is key to minimizing potential damage and repair costs. An infrared thermography camera can see the heat transfer characteristics common with water and helps show what is wet or damp and what is dry. Keep in mind, IR cameras don't see water, per se, but they see the evaporative cooling related to the water.
Thermography is defined as obtaining and analyzing thermal information using a non-contact thermal imaging device. An infrared camera does not measure temperature. Instead, it measures heat energy. Infrared technology doesn't see through walls and isn't X-ray vision nor is it night vision, but instead allows the user to examine the heat transfer characteristics of the objects around us. Thermal imaging can work in complete visual darkness since the visual light spectrum (what we can see with our eyes) and infrared spectrum are at different wavelengths (approx. 0.4 to 0.75 micrometers for visual energy vs. 1 to 1000 micrometers for infrared energy). The type of infrared thermography cameras that most thermographers use measure IR energy in the 8~12 micrometer "long-wave" wavelength range.
Using an infrared camera, warmer objects are typically lighter in color (red, orange, yellow, or white). Cooler objects are typically darker in color (blue, purple, or black). To an untrained eye, a bunch of odd patterns, shapes, and colors on the infrared camera's screen can easily be confusing or totally misdiagnosed. Issues such as cold air entry may look similar to missing insulation or the issue may be completed missed. To the properly trained infrared thermographer, however, these anomolies can be properly identified. When the infrared camera indicates evidence of a potential leak, for example, the issue should be confirmed with a moisture meter assuming the area in question is safely and physically accessible.
If properly done, a thermal image can also be "thermally tuned" to highlight the issue(s) of concern within the image and to maximize thermal contrast in the image or to 'filter' out heat transfer above or below a set temperature.
An infrared thermography scan entails going room to room in the building and analyzing the walls, floors, ceilings, heating/cooling registers, etc. of each area. The first thing that needs to be done is that the building to be scanned needs to be prepared well prior to the scan beginning. Furniture, book cases, and wall coverings (mirrors, paintings, etc.) should ideally be removed away from the walls. For a thermal scan to work properly, the bare walls should be visible to the camera as much as possible. A painting on a wall or a sofa or bookcase against the wall prevents the wall from being seen both visually and using the infrared camera. Also, heating or cooling equipment should be running at least 4 hours (12 hours is even better) before the scan is performed to help allow for a good temperature difference between interior and exterior.
By thermally conditioning the building prior to the scan, a good temperature difference (at least 12° F, but 18° F is even better) should exist between the building's interior and exterior. Remember, as noted above, for heat to transfer, there needs to be a difference in temperature between objects. This should provide ideal conditions to find heat transfer, and, as you know, infrared thermography is all about heat transfer. If a building's interior temperature is nearly the same as the exterior temperature, little heat transfer will occur, and there will be little to nothing be seen (and found) using the IR camera.
The hotter and cooler that two nearby objects are, the faster heat energy will transfer from the hotter to the cooler object. Also, certain materials have a higher thermal capacitance. Thermal capacitance is a measurement of how well an object or material retains heat. Water has a higher thermal capacitance than air. This is why water holds warmth longer than nearby air does. Understanding thermal capacitance is yet another example of why it is critical that a professional infrared thermographer be properly trained.
Missing insulation in various walls and ceilings.
This photo shows a very poorly insulated wall/cathedral ceiling junction. Every bedroom in this home showed the same phenomenon. Without doing an IR scan, this issue would have gone unnoticed until the homeowner wondered why the home was so cold in the winter and kept cranking up their furnace.
This attic access location lacks any insulation. The cold attic winter air can easily reach living space. Attic entrances (pushup panels, pulldown ladders, and doors) are common locations for heat gain/loss and lead to higher heating/cooling costs and less lower interior comfort. Most attic accesses (panels or doors) lack any insulation.
Recently, while inspecting a home, I found a roof leak alongside a dormer that would have totally been missed without performing an IR scan. Sometimes there are no stains visible, yet, on the interior ceilings or walls providing an indication of a leak. Moisture readings (100% saturation) of the areas confirmed active leaks. My client was very happy that he elected to have me perform the IR scan in addition to his home inspection and caught these 'hidden' roof leaks.
The above photos show a dining room ceiling. The first shows what was visible to the eye. The 2nd shows the hidden roof leak that I found when scanning the ceiling with my IR camera. The roof was leaking alongside a dormer above this area which would have gone unnoticed until, at some point, a stain would finally appear. The ceiling area was confirmed to be saturated using a moisture meter.
The above IR image illustrates the heat energy given off of by energized wiring (infrared vs. visual). This is a normal occurrence when wiring is energized (powered). A properly trained infrared thermographer will be able to decipher what is considered normal versus what may be considered excessive heating of wiring.
Note - WIN Home Inspection also offers Mold Testing. So, by having an Infrared Thermography scan and Mold Testing performed, we can better help determine if your new home has potential issues with water infiltration that have or could possibly lead to mold.
Learn more about Infrared Thermography here.
Matthew Steger, owner/inspector of WIN Home Inspection, is an ASHI Certified Inspector (ACI), a Certified Level 1 Infrared Thermographer, an electrical engineer, a PA Dept. of Ag. licensed pesticide applicator/WDI inspector, and a PA DEP licensed radon tester. He is fully PA Act 114 compliant. He can be reached at: 717-361-9467 or firstname.lastname@example.org. WIN Home Inspection has provided a wide array of home inspection services in the Lancaster, PA area since 2002.