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Infrared Thermal Imaging What's it Really Good For?

By
Home Inspector with JRV Home Inspection Services, LLC HOI 394

I have noticed quite a bit of blogging relating to using infrared thermal imaging cameras for home inspections. Some of these blogs are nothing more than an ad for how the home inspection company is ahead of the technological curve. But what really is the the truth about using thermal imaging as a home inspection tool.

The first and most important thing to understand about infrared cameras is they do not see through objects. That's x-ray folks. Infrared is thermal or temperature readings of the surface of an object. Now infrared cameras are extremely temperature sensitive. Because of this sensitivity they can display pictures in temperature gradients. The image may appear to have a great degree, no pun intended, of temperature differential, when in fact there is little temperature range.

 Notice the the image to the right. The temperature range is about 11 degrees. What are you looking at in this picture?

Missing wall insulation. The dark areas in the center of this infrared thermal image show clearly where the insulation company failed to fill the stud bay. The bays on the immediate left and right are only partially filled. Look closely at the right hand wall and the ceiling. Can you see the stud lines?

Now this is a great example of a good use of infrared thermal imaging. Heat and energy loss. Makes sense right, temperature sensitive camera-heat and cooling deficiencies.

What it is not really great for is a general inspection tool or a mold locater. Why? Because there must be ideal infrared conditions present to find problems such as a water incursion. Simply taking the camera out at the time of the home inspection and scanning the home will not necessarily reveal anything.

Which brings up another important aspect of the thermographers job, to know when and how to use the camera in order to locate an existing problem. Most infrared building diagnostic companies use spray racks to systematically wet the building in order to find a leak. They use the infrared camera along with a moisture meter to track back to the water source.

If your lucky during the day of the home inspection or very recently it has rained. Now you have a very good chance of locating a leak or source of a moisture problem. Of course rain is not the only source of water leaks in a building. A plumbing leak is just as common. The thing with a leaky pipe is a good home inspector will likely find it during the course of his inspection.

Having rain during the home inspection when using infrared is not the only needed thermal condition. Temperature differential is also very important. Lets say the inside of the home is 70 degrees and out side it is 58. The inside has been 70 for several hours. This is what I call a temperature equilibrium. The surfaces in the home have been at the same temperature for many hours with the outside temperature relatively close to the inside. Because of this the walls will appear to the infrared camera with very little detail.

As you can see infrared thermal imaging is far from an exact science. It is crucial that the person operating the camera is trained in the use of the camera, thermal dynamic principles, and interpreting infrared images. Owning an infrared camera and offering infrared as an ancillary home inspection service does not assure a skilled operator.

I use infrared primarily as an energy auditing and heat and cooling loss tool in CT where I perform home inspections. I have found infrared to be a fantastic device in this application. I have almost never used it to locate water leaks and when I have was disappointed in the results.

Okay, so what is infrared thermal imaging really good for? Everything I discussed here and much more. So long as it used within the parameters of its' limitations by a skilled operator.

James Quarello
JRV Home Inspection Services, LLC

To find out more about our high tech energy services click on the links below:

Learn more about our Infrared Thermal Imaging & Diagnostics services.Learn more about our energy audits, the Home Energy Tune uP®.

Posted by

James Quarello
Connecticut Home Inspector
Former SNEC-ASHI President
JRV Home Inspection Services, LLC

 ASHI Certified Inspector

To find out more about our other high tech services we offer in Connecticut click on the links below:

Learn more about our Infrared Thermal Imaging & Diagnostics services.

Serving the Connecticut Counties of Fairfield, Hartford, Middlesex, New Haven, Southern Litchfield and Western New London.

Comments (85)

Jimmy Breazeale
Sherlock Home Inspections - Coldwater, MS
Why, by George, John, I believe you did!
Jul 28, 2007 03:42 PM
John McKenna
InfraredClass.com - Dallas, TX
I am always amazed at how much personal agenda goes into a persons comments sometimes. If they could step back and take a breath, they could see the simplicity of what is being said. This debate is a perfect example.  This is why it has been one of the strongest revelations I have seen in life, is that pride can make the most intelligent person look stupid.  Bad attitude makes it hard to receive instruction, more than any other single factor.  It bleeds over into everything, and most cannot see it's power over their mind. IMHO. Your mileage may vary.
Jul 30, 2007 05:15 PM
James Quarello
JRV Home Inspection Services, LLC - Wallingford, CT
Connecticut Home Inspector

John,

That's a very interesting statement coming from you. I am always amazed at how much personal agenda goes into a persons comments sometimes. Well ain't that the truth!

If you were to read the original blog again, I think you are correct concerning a  personal agenda. My purpose was simply an attempt to educate people on infrared. Why? Because I see to many unskilled people are using it. How do I know? Because I see the erroneous information here on AR and other places on the web. I fortunately have a camera and training which allows me, most often, to know hype when I see it.

You know a lot of good information was exchanged on this thread. I took away some new knowledge. I certainly hope you did too, John.

Jul 30, 2007 11:16 PM
John McKenna
InfraredClass.com - Dallas, TX

Yup, good info did indeed surface to the top.  It took a while for some folks to arrive at the simple truth, but it finally got through.  Go back and read how much effort was made to oppose my posts, but it was finally seen in the end that I was stating the simple truth.  That is what I am talking about.  Use a moisture meter to verify an IR image.  Why was that so hard to understand, for so long?

 BTW...


U.S. Department Of Energy Now Recommends A Thermographic
Scan Be Done Before Purchasing A House, Even On New Homes
 

http://www.eere.energy.gov/consumer/your_home/energy_audits/index.cfm/mytopic=11200 

What is thermal Imaging good for?  Home Inspections.

Have a nice day.

From: John McKenna

Certified Building Science Thermographer (#33493) 

Aug 06, 2007 08:03 AM
James Quarello
JRV Home Inspection Services, LLC - Wallingford, CT
Connecticut Home Inspector

John,

Using moisture meters to verify infrared images was not what the subject of this blog or was the focus of the discussions on this thread. It was your entire focus, not mine or others here that added useful and insight information on infrared.

My point was and still is that an infrared camera has limitations as was pointed out in my original blog and through out the thread. Those limitations must be considered and incorporated into the thermographers inspection.

As far as the DOE you should read that advice a little closer. Their recommendation is for ENERGY loss, not as part of general home inspection. This is the heading and introductory paragraph.

Thermographic Inspections

Energy auditors may use thermography-or infrared scanning-to detect thermal defects and air leakage in building envelopes.

Where does it say home inspectors? You are the second person on AR to take this information out of context and try and twist it to your advantage.

As far as your cerification, it's not a level 1 thermographer. It is a certification by FLIR, not an industry certification. Similar to all those cerifications for mold testing. They are not industry certs, just something a lab puts together to make you look qualified to sample for mold. More or less meaningless.

Aug 06, 2007 09:36 AM
John McKenna
InfraredClass.com - Dallas, TX

My comments about IR scans being verified by a moisture meter were come against and then finally agreed to.  Some said I was doing it wrong, but it was then proven correct. Of coarse there has been more than one point made in the discussion.  I am making an observation about this point.

As far as the  thermal imaging being recommended by the DOE it states the following:

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 audit, 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.


It states that IR scans are used by energy auditors and IN ADDITION you should have a scan done  before purchasing a HOUSE.  It also mentions the IR scan can detect moisture and insulation problems.  These are all verifying that an IR scan is useful in a home inspection.  To say moisture and insulation problems have nothing in common with a home inspection is to deny reality.  Please don't twist things,  but rather read the entire article. Read the word "ADDITION", which means beyond just an energy inspection, get a thermal scan before you buy a house.  

To say a thermal imaging camera cannot be used effectively in a home inspection is just ridiculous.  Inspectors are using them by the hundreds every day in north America, and having great results. If my competitors do not want to use an IR camera, that's OK with me.  I'll take their business.

When I went to the my building science training, as well as many others of those who went at other times, it was testified to by the level I, level II and level III thermographers at the classes.... that the BUILDING SCIENCE TRAINING did more to prepare them for home inspections than all the other training they had up to that point.  I'm just telling what I have seen and heard.

Even if you have Level I, to Level III training, if you do not test, document and report according to prescribed and legally approved scientific methods, your report is not accepted as being approved by those set of industry standards.

The reason all of that does not matter is because we, as home inspectors, are not trying to prove anything, except the conditions present at our inspection.  We are not giving exhaustive invasive instructions and bid proposals or stress and load analysis. We as home inspectors need only to document the wet spot and it does not matter if we document the reflectivity of the surface, or the emissivity of the materials, or the temperature loss through radiation or evaporation, or record the delta T factor and the cameras calibartion settings, or bla, bla, bla,... So much of the scientific standards associated with thermography are not needed to document that there is indeed a "moist area in the ceiling".  We are simply using the IR camera to help locate and document a condtion that is reported to the client.  Lets be real.

To say the  training is useless, shows a bias toward your own agenda that fly's in the face of logic.  To say training is meaningless is illogical.  To get Level I training and then to think that your report automatically has more credibility is not true, because the home inspector does not meet, nor is he required to meet scientific industry standards in their methods and reporting 99% of the time.

If a building science thermographer and a level 1 thermographer report the presence of a wet spot, it is still just a wet spot, even if it goes to court. The skill of the operator and the witness of a moisture meter, and invasive verification will establish the facts, not your credentials.

Some thermographers use their IR cameras exclusively to find moisture problems, because it works so well.  Others, as you have experienced, have had disappointing results finding moisture problems.  But that may not be the cameras fault.

Aug 06, 2007 05:19 PM
James Quarello
JRV Home Inspection Services, LLC - Wallingford, CT
Connecticut Home Inspector

John,

The DOE (Department of Energy) is not referring to home inspections. They are speaking of energy audits. Although you could take it mean an infrared scan be done as part of a home inspection. As you know? roof scans are difficult at best and must be done at specific times. Not something you are likely to do during a home inspection unless you plan to be there after sunset.

Also just to be clear I did not say training is meaningless. The certification is what I was referring to because it is specific to FLIR.

We as home inspectors are not trying to prove anything??? You have a unique talent for simplifying what  home inspectors do to fit your point.

One last thing, what this blog was concerning is that infrared has to be done when conditions are right to yield good information. A point you seem to avoid. I did an energy audit yesterday. Infrared is a part of that service, but the audit does not rely on the camera. The outside temperature was about 75 degrees. The inside temperature was about 75 degrees. What did I see with the camera? Not much and I have a B-2. I could just imagine what I would have not seen with a B-CAM.

That was and is the theme of this blog. The limitations of the camera and that it must be used at times that will maximize its' effectiveness. Some do not want to go there because it will take away the infrared camera mystique. Moisture meters and wet spots, if it was all only that simple.

Aug 06, 2007 11:38 PM
Scott Patterson, ACI
Trace Inspections, LLC - Spring Hill, TN
Home Inspector, Middle TN

OK, lets look at it from an economic standpoint.  A good IR cam will cost, what around $8,000 +.  If you use this as a tool during your normal home inspection, do you charge extra or just absorb the cost of the new tool?  I could see an extra fee of lets say $100 on a normal size home in addition to the inspection fee.  If the client want an IR scan of the home it is an additional fee of $xxx. 

So if you can get an extra $100 per inspection, you could see a return after a year of use.  I would not see every home buyer wanting one.  Heck, I have a hard enough time selling a radon test even when the EPA says that we have some of the highest readings in the country in my area. 

So what do folks charge to use an IR camera with a home inspection and stand alone without one?  Do you charge an hourly rate?  My hourly HI rate is $175 per hour, would it be the same for an IR cam?

I really would like to know as I might be adding one to my tool box soon.

Aug 07, 2007 03:09 AM
Anonymous
Will Decker

Some points:

1) I whole heartedly agree that HIs should get, at least, level 1 certification before they use IR in their inspections.  This is not only so that the know what they are doing, but so they have a certification (which, when you come right down to it, is nothing more than some group saying that you are qualified, whether you actually are or not) to protect themselves from liability.

2) I have been doing IR for over 2 years now.  I am certified and have a post graduate degree in Physics and learned this technology back when I was working that the University of Chicago.  I am very familiar with it (in fact, I have written a course which was recently licensed by the state for CE credit on IR for Home Inspection), but still run into problems every now and then.  Book learning AND experience are both key.  I use IR on EVERY inspection.

3) Every HI I have ever run into who disputes or downplays the validity of IR in home inspections is a guy who doesn't have one and wishes that they did and hates losing inspections to those that have one.  Not saying that is the case with everyone.  It is only my experience.

4) I have found moisture intrusion and leaks many times.  Most times thay are from pipes behind walls that a visual inspection would never have found.  Most times, the surface displays no signs of water.  Maybe it is our area (Chicagoland), but that has been my experience.  Bad window flashing is also a big one.  Always back it up with a mositure meter.

5) When another inspector warns me about increasing my liability by doing IR, or any of the other things I do that are above and beyond the pretty simple and easy SOP that we have here in Illinois, I ask him, "Why are you so concerned with my liability?".  Usually, it comes down to my having booked an inspection that they didn't.  If you do a better job and offer service above and beyond your competition, you will get more work and be able to charge more for it.  I am sorry if others choose not to raise their standards (and fees) but the success of their business is not my problem.

6) Yes, I market my services.  It's called advertising.  HIs do that, at least the ones who rely on inspections to pay their mortgage and college tuition for their kids and the like.  I also market myself to contractors, lawyers, water damage companies, plumbers and pretty much anyone that I can think of that needs thermal imaging.  Nothing to be ashamed of.  It's just business.

 Hope this helps;

 

Aug 07, 2007 06:31 AM
#74
Anonymous
Anonymous

James,

I agree... thermal imaging has limitations.  But there are tricks to the trade to overcome some of those limitations.  I have been able to find things with my Bcam, that those with more expensive IR cameras were not able to find.  

Will,

Very good post.

Aug 07, 2007 02:01 PM
#75
James Quarello
JRV Home Inspection Services, LLC - Wallingford, CT
Connecticut Home Inspector

Will,

I would absolutely agree there are tricks to help overcome the limitations. I know a few and do use them when doing scans. My point has been there are times, like my recent example, when you are going to run up against bad conditions. Now I could have pulled a very obvious trick out of the bag and helped myself with that scan. Unfortunately the homeowners were there and one was a disabled person. I did not have the luxury of time because of this obstacle. But it was all good, as I said my audit does not rely on the camera and I was able to provide my client with exactly what she needed.

Aug 08, 2007 12:38 AM
Scott Patterson, ACI
Trace Inspections, LLC - Spring Hill, TN
Home Inspector, Middle TN

OK, let me ask this more direct question!

 How long/how many jobs did it take to pay for your camera?  Or if this has not happened yet, what are you projecting?

Aug 08, 2007 01:52 AM
James Quarello
JRV Home Inspection Services, LLC - Wallingford, CT
Connecticut Home Inspector

Scott,

What my business and your business have in common is really very little other than we do home inspections and related services. So what you need to do is figure out what you can charge for your infrared service in your area and how you are going to market it. I would say that a one to two year return would be expected.

Aug 08, 2007 02:06 AM
John McKenna
InfraredClass.com - Dallas, TX

Free Online BCAM Thermal Imaging Course.

Check it out.
http://www.infraredtraining.com/courses/bcam_basics.asp

Aug 08, 2007 04:28 PM
Jimmy Breazeale
Sherlock Home Inspections - Coldwater, MS
Thanks, John!  Something for me to do Sunday afternoon.  That and Will's course will provide a good general prep.
Aug 08, 2007 06:56 PM
Gene Allen
Fathom Realty - Cary, NC
Realty Consultant for Cary Real Estate

I just saw this and had to comment.  I am a real estate agent and the buyers of my listing hired a HI who used a FLIR device.  He told me he could detect deficient electrical outlets and determine if the airflow from the HVAC ductwork was deficient.  I think from reading your comments he was overstepping a bit.  It was a neat device and I would probably want the HI on the buyers side to have one but only if he was trained properly and could interpet the data.  I used to work on FLIR was I was in the Navy but our planes used it to target things besides water leaks.

By the way, good debates.

Aug 15, 2007 12:34 PM
Jimmy Breazeale
Sherlock Home Inspections - Coldwater, MS
Gene, a knowledgeable inspector can sniff out moisture problems in most cases. IR can be and is a very useful tool, but as has been shown here it is often misused and/or misrepresented.  The FLIR cam and appropriate training represents an investment of 9-12K for the HI.  That isn't just spending cash for most of us.  The greatest advantage that I can see, in the context of a standard home inspection, is that IR has the potential to cut down on inspection time.  Do not hesitate to keep among your recommended group of inspectors those who are experienced, but do not have the IR cam.  I can personally guarantee you that the experienced inspector without a cam will produce a more reliable product than the inexperienced, not-so-well trained inspector with a cam every time.
Aug 15, 2007 05:45 PM
Mike Jewett
JaxHomeSpy, LLC - Jacksonville, FL

Thermal imaging used simply as an additional tool is great. I would always let clients know up front that it cannot see through walls and that I would only use it as an additional assurance. If I were to find something that looked off, I would inspect further and use my eyes, ears and other tools to find out the exact problem and disclose it.

On another note- thermal imaging is great for race horses.

Aug 16, 2007 10:53 AM
Mike Gillingham
Eastern Iowa Inspection Services LLC - Walker, IA

I would like to add one thing to the mix. When I do an IR scan of a house I make sure to explain to the client what I am doing and set their expectations accordingly. I believe this is a very important part of being an excellent home inspector. When expectations are set in advance everybody wins. HI, Realtor, Seller and most importantly the BUYER. If someone expects superman then they will be let down every time. If you explain the limitations of the inspection process as well as other technology you are using then expectations are set and they are grateful for what is found. Don't misunderstand; you are not going to poop on your services by explaining these things. You must articulate that they have come to the best guy around and even the best aren't superman.

Mike

Jun 01, 2009 02:21 AM
James Quarello
JRV Home Inspection Services, LLC - Wallingford, CT
Connecticut Home Inspector

Mike,

That is the general idea of this blog. The perceived or marketed expectations of thermal imaging compared to when and how it can be used effectively. You should be explaining to the client that using thermal imaging may not reveal any problems, even when they may be present, due to the limitations of  the equipment because of temperature, time of day, weather etc. Which is my problem with IR cameras used during home inspections. Often the inspection is done around someones schedule, not around ideal thermal imaging conditions.

Jun 01, 2009 11:52 PM