What Do Home Inspectors Need to Know About Thermal Imaging?

November 9, 2020 | 
thermal imaging

Are you considering investing in thermal imaging equipment for your home inspection business?

If you are, you’re not alone. Infrared imaging technology can be an invaluable asset to a home inspector’s toolbag, as it is a noninvasive way to identify many of the major issues commonly found in homes.

In this post, we’ll take a closer look at what thermal imaging is, some common misconceptions about the technology, do’s and don’ts for home inspectors using infrared imaging, and a few tips for homeowners preparing for a thermal imaging inspection.

What is thermal imaging?

Heat gives off infrared light, which is on the part of the electromagnetic spectrum that isn’t visible to the naked eye. A thermal (or infrared) imaging device translates thermal energy — that is, heat — into visible light. 

Thermal cameras take pictures of heat in the same way that your smartphone or camera takes pictures of visible light. Since thermal cameras ignore the visible light portion of the spectrum, their results aren’t hindered by solid obstacles like walls, roof beams, or bulky furniture. 

 The relative results appear on photos as colors:

  • Purple for cool temperatures
  • Red for medium temperatures
  • Yellow for hot temperatures

As a home inspector, this means you can use thermal imaging to analyze a property for any issues that would result in heat discrepancies on surfaces.

How Thermal Imaging Can Help Your Home Inspection

Although not every successful home inspector chooses to invest in infrared imaging equipment,  there are quite a few reasons you might consider adding thermal imaging to your list of services. 

Using a thermal imaging scan can help you detect small anomalies related to heat, whether they be too hot or too cold, such as:

  • Plumbing leaks or clogs — Using infrared imaging, you might be able to spot the location or a clog or leak before the homeowner or plumber knocks holes in walls to find it.
  • Water damage — The thermal imaging scan should reveal a temperature difference between wet and dry areas in a home’s walls, ceilings, and floors. This is because moisture adds thermal mass to an area, causing it to hold onto heat longer than its drier surroundings.
  • Hidden roof leaks — Thermal imaging cameras can create a detailed image of the roof, indicating the areas where moisture is trapped. This is a sign of the source of a leak or where there may be compromised insulation. These infrared images can quickly narrow the search for roof leaks without having to damage or puncture the roof.
  • Electrical issues — An infrared scan can locate hotspots indicating overloaded circuits, old circuit breakers, electrical faults, and overheated electrical equipment.
  • Missing or damaged insulation — Since insulation’s role is to insulate heat in the home, a thermal scan should show any spots where the material is missing or no longer doing its job.
  • Flue leaks  In the US, 10,000 carbon-monoxide-related injuries occur every year, and the most common cause is damaged or malfunctioning chimneys and flues. A thermal inspection on an operating heat system can identify leaks and backdrafts that might lead to carbon monoxide poisoning.
  • Pest infestations  Significant, active infestations of termites, rodents, and other pests produce visible heat that a thermal imaging device should capture.
  • Energy loss — A thermal imaging scan will detect and pinpoint losses of energy caused by a leaking air conditioning or heating system, structural defects, or broken window seals.

Types of thermographic tools

If you’re considering getting into thermal imaging for your home inspection business, it helps to understand the variety and scope of tools available. While there are a few tools out there that capture thermal radiation, not all are up to the task of an in-depth, detailed home inspection.

  • Spot radiometer (point radiometer): This is the simplest tool of the bunch. It’s directional, meaning it measures radiation as you point it at an area. It is mostly used for evaluating tools and equipment.
  • Thermal line scanner: This tool shows radiant temperatures along a line. The scan is then superimposed over a picture of the area. It is often used for commercial procedures where temperatures need to be homogeneous across an area.
  • Thermal imaging camera: This tool is the most accurate option; it produces a two-dimensional thermal image of an area. In a home energy audit, a thermal imaging camera is the only tool sensitive enough to detect heat loss.

What thermal imaging is NOT

You’ll notice that the above section didn’t mention that thermal imaging allows you to “see through walls.” That’s because even though thermal imaging technology feels like something out of a futuristic sci-fi movie, it’s important to remember that thermal imaging is not the same as x-ray vision. It’s a visual, surface-level inspection that simply translates heat into the visible spectrum. 

That isn’t to say thermal imaging won’t help you get an idea of unseen issues; however, the only issues that will show up are ones that relate to heat discrepancies. And the inspector is still the one who needs to interpret the data in front of him or her.

A thermal imaging device is also not a moisture meter. A thermal imaging camera will detect the heat from excess moisture in an area, but a thorough inspector will confirm those results using a non-penetrating moisture meter. Thermal imaging is a great way to narrow the search, but you’ll need to follow up on those results with more specific tools.

It’s also important to keep in mind that a thermal imaging scan doesn’t differentiate between normal heat variations and abnormal ones. 

For example, many roof elements might appear on the scan as abnormalities — and to an untrained eye, they might indicate water damage. But HVAC equipment and reflecting roofing materials also give off heat. As a home inspector, you’ll need to determine where these elements are and be sure to interpret your thermal imaging results properly.  

A thermal imaging scan isn’t a catch-all and shouldn’t be treated as such. However, when used properly, infrared technology can be a time-saving and invaluable addition to a home inspector’s bag of tools.

Dos and don’ts for home inspectors using thermal imaging

You may be drawn to thermal imaging because this high-tech service can help set you apart from the competition in your area. It’s true that many customers are impressed by a home inspector’s ability to use infrared imaging, and some real estate agents only refer their clients to inspectors who offer thermal imaging services.

If you choose to start implementing thermal imaging in your home inspections, keep these tips in mind to make this service work well for you:

  • DO explain the abilities and limitations of the technology to your clients. Many are under the impression that infrared technology is as good as seeing through walls, so it’s important to make them aware of how thermal imaging really works.
  • DO provide follow-up inspections after repairs are done (for an additional fee).
  • DO provide the data and photos found with infrared cameras in your home inspection report – including a “normal” photo side by side with an infrared photo of the same area to help your client know what they’re looking at.
  • DO interpret the data you find. Your clients need to know if something is a critical issue, or just something to be aware of going forward.
  • DON’T use overly-technical language during your inspection that confuses or alarms your clients. Keep things simple.
  • DON’T offer to make repairs; it’s against InterNACHI’s code of ethics because it is a conflict of interest.

How homeowners can prepare for a thermal imaging inspection

If you’re a homeowner ordering a pre-listing inspection or are preparing for a home inspector to enter your home, you may want to take action to prepare for as accurate a thermal imaging inspection as possible.

Keep in mind that the most accurate thermal inspections take place during large temperature differences between indoors and outdoors. In the U.S., therefore, they generally take place in winter in northern states and summer in southern states. If possible, schedule your inspection during the time of year that contrasts your climate with your indoor temperature.

Be sure to set your air conditioning or heat to a difference of 20 degrees Fahrenheit (14 degrees Celsius), if possible.

Then, focus on making it easier for the inspector to access the structural components of the home. Even though an infrared camera isn’t bothered by furniture or physical objects, your inspector may still need to get close to walls to get a good image — so it’s a good idea to move furniture away from exterior walls and remove curtains and drapes from the windows.

Thermal imaging isn’t a magic solution, but it’s still a valuable tool

While society still hasn’t developed a handheld device that sees through walls, thermal imaging can still bring a great deal of value to your home inspection services. Infrared technology is a noninvasive way to pinpoint issues that relate to heat discrepancies, like leaks, plumbing issues, and electrical malfunctions.

Offering thermal imaging can be a useful way to make your home inspection business stand out from the competition and provide added value to your clients — plus, it makes your inspection reports look that much more impressive. What’s not to like?

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