What does an infrared camera do?
If you are thinking of using or requesting infrared for a home inspection, the first thing you need to understand is that infrared cameras are just fancy thermometers; they translate surface temperatures of objects into colors thereby creating an image comprised of temperature differentials. That is all they are. Fancy thermometers.
How can this fancy thermometer be used on a home inspection?
The benefits and limitations for infrared cameras on home inspections can be confusing, so let’s look at an example of how an infrared camera could be used on a building inspection to see if this brings some clarity.
If you took a thermal camera and pointed it at a hot surface, say, an exterior wall of a building that is being heated by a hot summer sun, do you know what your image would look like? A mostly yellow and red blob of heat. This is because everything is hot. There would be almost no temperature differential so the whole image would be a wash of heat. Do you suppose this image would help you see behind this wall or find a latent moisture problem? No!
Now let’s go back to that same wall at the end of this hot summer day. When the sun goes off the wall and the building starts to cool, it is possible that the camera could reveal a latent moisture problem. If parts of the wall were wet, these parts would cool more quickly due to evaporation. This would create a thermal anomaly or a change in temperature which could be “seen” by a thermal imaging camera and could lead you to a possible hidden moisture problem. In this case, the image taken from a cooling, partly wet wall assembly could be very useful.
Now let’s look at this same wall and assume that it does have a moisture problem when it is raining in the winter, but your home inspection is done in the summer, when it has not rained for over a month. You take your image of this dry wall assembly cooling off at the end of the day: what will this image look like? Well…. Hard to know.
- If the moisture problem has caused rot in the wall, it could create a thermal anomaly as the damaged wood heats or cools differently than the sound wood.
- If this were a newer moisture problem that had not yet caused damage to the wood, you may not get an image that is very helpful. You could even be misled into believing the wall had no moisture problems when in fact, it does.
- There are other wild cards at play. What is the exterior wall made of: brick, stucco, wood, synthetic stucco? These different siding materials would present different thermal challenges and could limit the usefulness of this tool.
So, is this expensive piece of equipment really going to see behind walls and insure a home buyer they have no latent or concealed moisture problem? No. If you are lucky, and conditions are right, you might be able to get a useful image that leads you to a latent or concealed moisture problems, but it is far from a guarantee. The variability of environmental conditions at the time of inspection make it difficult to offer comprehensive thermal imaging inspection as part of a home inspection, however, a quality thermal camera can still be a very useful tool on a home inspection.
Practical uses for infrared on a home inspection
I use my infrared camera for five primary functions during my home inspections. The first two are services for which I charge an additional fee because these procedures add significant time to my home inspection. The last three are included in my home inspections as the camera is employed as any other tool, as another way of looking at a building. This list below will help you better understand the types of questions you may be able to answer about your prospective building using a thermal imaging camera in the midst of a complete home inspection.
5 Primary ways to use infrared camers in a home inspection
- Insulation verification and heat loss or air leakage
- A complete interior scan for thermal anomalies
- Checking radiant floor heating systems
- Shooting ceilings below 2nd floor plumbing to look for signs of hidden leaks
- Spot checking areas I am concerned about due to other visible red flags, I think especially of vaulted ceilings.
Infrared camera use: details
Insulation verification. If a well-insulated wall or ceiling assembly and a tight-house is important to your client, you may want to recommend this additional service. It is important to understand that most old homes are not well insulated and leak a lot of air. Retrofitting wall insulation is complicated and likely not very cost-effective depending on the region. As such, most home buyers do not want to pay for this additional service during a home inspection. This type of inspection is generally done as part of an energy audit.
A complete thermal camera inspection is well-suited to newer homes and especially new construction where the builder could repair a poorly insulated wall or ceiling assembly prior to close. It is also a great diagnostic if the buyer is hoping to retrofit the house for energy efficiency.
Checking radiant floor heating systems can be difficult to inspect, especially on hot summer days when ambient temperatures are similar to the temperatures on a heated floor. The thermal camera can help you see if the in-floor heating system is operating correctly. I use mine all the time on home inspections and it is very helpful.
Scanning. Using a thermal camera to scan the ceiling below plumbing is a nice way to check for hidden plumbing leaks in the ceiling; I routinely perform this inspection after running all plumbing.
Spot checking. Sometimes I find areas in a house that I am concerned are having moisture problems or insulation problems or even over-heating problems such as over-heating wire in the electric panel. The thermal camera can help a home inspector add more information to a given red flag.
I hope this article helps you understand how thermal cameras can both help and mislead your home inspection; and I hope you get a sense of the types of questions you can answer during a home inspection using thermal imaging. Remember that thermal cameras can be an effective tool but they have significant limitations.
Dylan Chalk is the owner of Seattle-based Orca Inspection Services LLC – www.orcainspect.com. He is the founder of ScribeWare inspection report software offering innovative and simple report-writing solutions – www.getscribeware.com. He is also the author of The Confident House Hunter – a book to teach home buyers how to look at and understand houses: Cedar Fort Press Due out August 2016 – www.dylanchalk.com