Author Topic: Thermal imaging diy?  (Read 1417 times)

middo

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Thermal imaging diy?
« on: October 28, 2021, 09:41:21 PM »
Hi Everyone,

I was looking at trying some thermal imaging at home to try to eliminate a few of the more problematic heat loss/gain issues we have at home in our old house.  I came across a thing that plugs into a smart phone, and turns it into a thermal camera.  The cost is around $200 Australian (say $150 US) which is a bit pricey as I don't know how much I will use it.  However, I can see that I could easily save that in lessening our winter heating and summer cooling costs.

The gadget is a FLIR ONE like the one in this link: https://www.amazon.com/FLIR-ONE-Thermal-Imager-Android/dp/B00W5PRY52

Has anyone used anything like this with their smart phone?  Or bought a thermal camera themselves and got much use out of it?  Any feedback would be really useful.

jeromedawg

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Re: Thermal imaging diy?
« Reply #1 on: October 28, 2021, 09:47:29 PM »
Hi Everyone,

I was looking at trying some thermal imaging at home to try to eliminate a few of the more problematic heat loss/gain issues we have at home in our old house.  I came across a thing that plugs into a smart phone, and turns it into a thermal camera.  The cost is around $200 Australian (say $150 US) which is a bit pricey as I don't know how much I will use it.  However, I can see that I could easily save that in lessening our winter heating and summer cooling costs.

The gadget is a FLIR ONE like the one in this link: https://www.amazon.com/FLIR-ONE-Thermal-Imager-Android/dp/B00W5PRY52

Has anyone used anything like this with their smart phone?  Or bought a thermal camera themselves and got much use out of it?  Any feedback would be really useful.

LOL! I just got one of these to try out and play around with. So far I'm not super impressed. It's a cool gadget and maybe useful for located beams and studs but whatever you're looking for needs to have a significant heat signature. If everything in your house registers close to the same temps as the things behind the walls, it's not going to be of much use IMO. I've been trying to figure out how to use it to 'map' the source of a wet wall in our home and it's not that helpful. I think it's probably more helpful with identifying potential live leaks, which I don't think is the case with whatever is causing the wet wall. It is interesting to use albeit a bit awkward.

DoingMe

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Re: Thermal imaging diy?
« Reply #2 on: October 29, 2021, 08:28:42 AM »
A number of years ago, we rented a Flir thermal imaging camera from our local big box home improvement store to try to locate areas of heat loss as well as making sure things like the circuit breakers were not overheating, etc.

We did find many areas that needed caulking and the like.  We also found whole bays in the walls that the original builder neglected to insulate or were insulated improperly.  It was well worth the expense.

jeromedawg

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Re: Thermal imaging diy?
« Reply #3 on: October 29, 2021, 12:26:44 PM »
A number of years ago, we rented a Flir thermal imaging camera from our local big box home improvement store to try to locate areas of heat loss as well as making sure things like the circuit breakers were not overheating, etc.

We did find many areas that needed caulking and the like.  We also found whole bays in the walls that the original builder neglected to insulate or were insulated improperly.  It was well worth the expense.

I'm guessing the trigger grip ones may offer better quality imaging/output than the entry level FLIR One. It would be interesting to try one of those out... the FLIR ONE is neat because I can definitely see the studs/beams but only if I point the camera higher up. When I try to find them near the windows or below windows, they won't show up for me - I'm wondering if it's because of the uniformity in surface temps though that's causing problems.

Askel

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Re: Thermal imaging diy?
« Reply #4 on: October 29, 2021, 01:02:59 PM »
I've spent way too much time screwing around with a FLIR Lepton in grad school.  (https://www.flir.com/products/lepton/

You have to be careful with cameras of this quality, as often what you use to view the results will dynamically recalibrate the display, so "blue" pixels might mean completely different temperatures when pointed at two different things. 

Second, the physical parameters of these camera can dramatically impact the results based on what you are looking at and how close you are to it.  Put simply, a pixel represents the average temperature of what it was pointed at. Up close, that pixel might be a couple centimeters in size, from far away, it may be taking the average temp over a couple of feet. 

They end up being a fun toy, but for home use- I find one of those cheap laser thermal infrared thermometers a lot more useful. 

That doesn't stop me from wanting to put one of the spot thermal infrared sensors and a cheap laser range finder together on a couple of servos and let it work it's way around the room and build a 3d image colored by temperature. :) 

jeromedawg

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Re: Thermal imaging diy?
« Reply #5 on: October 29, 2021, 01:13:26 PM »
I've spent way too much time screwing around with a FLIR Lepton in grad school.  (https://www.flir.com/products/lepton/

You have to be careful with cameras of this quality, as often what you use to view the results will dynamically recalibrate the display, so "blue" pixels might mean completely different temperatures when pointed at two different things. 

Second, the physical parameters of these camera can dramatically impact the results based on what you are looking at and how close you are to it.  Put simply, a pixel represents the average temperature of what it was pointed at. Up close, that pixel might be a couple centimeters in size, from far away, it may be taking the average temp over a couple of feet. 

They end up being a fun toy, but for home use- I find one of those cheap laser thermal infrared thermometers a lot more useful. 

That doesn't stop me from wanting to put one of the spot thermal infrared sensors and a cheap laser range finder together on a couple of servos and let it work it's way around the room and build a 3d image colored by temperature. :)

Are there specific FLIR models or other brand thermal imaging cameras that you do recommend?

Askel

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Re: Thermal imaging diy?
« Reply #6 on: October 29, 2021, 01:32:01 PM »
Unfortunately, no good recommendations.  My experience goes pretty much from low cost developer models (that I assume are the basis for most consumer models, but can't be certain) to really high end FLIRs that I specifically did not want to know the price tag of when they were attached to a drone I was piloting. :D 

But try one of those $25 laser thermometers first.  They're surprisingly useful and have been really helpful in pinpointing places I need to work on insulation in our house. 

Plus I can completely nerd out on how well our wood stove is drafting with it by taking chimney temperature measurements. 

jeromedawg

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Re: Thermal imaging diy?
« Reply #7 on: October 29, 2021, 01:59:50 PM »
Unfortunately, no good recommendations.  My experience goes pretty much from low cost developer models (that I assume are the basis for most consumer models, but can't be certain) to really high end FLIRs that I specifically did not want to know the price tag of when they were attached to a drone I was piloting. :D 

But try one of those $25 laser thermometers first.  They're surprisingly useful and have been really helpful in pinpointing places I need to work on insulation in our house. 

Plus I can completely nerd out on how well our wood stove is drafting with it by taking chimney temperature measurements.

Heh, I do have one of those laser thermometers. I also purchased a moisture meter too. I really need to try to pinpoint areas of the wet wall condition to help better understand what is happening on the outside wall to specifically cause this.

Jon Bon

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Re: Thermal imaging diy?
« Reply #8 on: October 29, 2021, 02:02:50 PM »
Laser thermometer for the win.

I have used it bunches of times to find hot/cold spots. Costs like 15 bucks.

jeromedawg

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Re: Thermal imaging diy?
« Reply #9 on: October 29, 2021, 03:00:25 PM »
Laser thermometer for the win.

I have used it bunches of times to find hot/cold spots. Costs like 15 bucks.


In terms of looking for the cold/hot spots what degree or point degree of difference are you really looking at particularly when it comes to drywall? Is a 1 degree or even .5 degree drop in difference commonly indicative?

BudgetSlasher

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Re: Thermal imaging diy?
« Reply #10 on: October 30, 2021, 09:23:53 AM »
I have an older version of the FLIR ONE. As has already been mentioned if everything is the same temperature you will have no result.

The software does adjust for this by changing the color scale so when temperatures are close together the difference between blue and white can be only a couple degrees, whereas if you are looking at something hot like a heating duct or a wood stove there is a large difference between colors (that also washes out smaller differences). In a house I find this annoying as the scale can differ from one room to another (heck I have had rooms where a empty wall, a view with the waste heat from a GFCI, and a laptop in frame all have different scales). This means to compare things that are not in the frame together you need a numerical value, luckily there is a crosshair in the center with a temperature readout.

If you live somewhere with a sizeable temperature difference between inside and outside they can be handy. I've found where outside air leaks in (during our heating season it shows as a dark blast pattern) where  inside air is leaking out (during heating season it shows as a red to white blast pattern) stud bays where insulation was missing (during heating season dark colors inside and red to white outside)
 finding the location of our septic tank (during the winter the ground is warmer there) and I've used it to find a heat duct that was floored over (showed a hot spot on the floor). I've also used it because I have it for little things or things I could do otherwise like tracing heating duct routing in the walls the hot spots and spotting deer in the yard at night.

If I were you and I knew or strongly suspected that my house had air sealing or insulation shortfalls that I could correct ... some corrections mean opening walls ... I would try to rent one first, but if I couldn't rent I would buy. Just remember for best results you should use it on colder or hotter days.

One last thought, outside use is best to be done at night. The sun beating down on materials, even in the winter, can add heat and wash out meaningful results.

gooki

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Re: Thermal imaging diy?
« Reply #11 on: October 30, 2021, 11:34:09 PM »
I purchased a mid tier reconditioned FLIR thermal camera a few years back. Did what I needed to do with it and then sold it on for what I paid for it.

middo

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Re: Thermal imaging diy?
« Reply #12 on: October 31, 2021, 01:38:13 AM »
Thanks for all the information everyone.  I now have a bit more to think about.  Temperature gradients are not normally huge here, as we don't have snow, and few days above 35 Celsius.

I will keep researching.  Fortunately I am not impulsive and haven't bought the first thing I saw.

deborah

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Re: Thermal imaging diy?
« Reply #13 on: October 31, 2021, 03:42:40 AM »
Your local library may have one of the $15 ones for loan. My library has a home energy kit that includes a killawatt and this and a few other things as well as an instruction booklet and your own notebook for results. A few years ago we had a thread where we found that people from all over the world, including several Australian states, had stuff like this in their library, so itís possible that yours has stuff. The thread was about killawatts, not the thermal imaging gadget, but my library kit includes both, and yours may too. The first time I borrowed the kit, I had to wait for a while, and the weather was pretty average, so it wasnít much use, but then I borrowed it in the middle of summer and got great results. They had increased the number of kits and there was no waiting time.

lutorm

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Re: Thermal imaging diy?
« Reply #14 on: November 01, 2021, 01:51:34 PM »
Another thing to remember when using these infrared cameras is that the conversion from IR flux to temperature depends on the emissivity of the material, and the readout makes an assumption about what that is. Metal, for example, has lower emissivity and will appear "colder" than it really is.

Jon Bon

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Re: Thermal imaging diy?
« Reply #15 on: November 04, 2021, 12:18:06 PM »
Laser thermometer for the win.

I have used it bunches of times to find hot/cold spots. Costs like 15 bucks.


In terms of looking for the cold/hot spots what degree or point degree of difference are you really looking at particularly when it comes to drywall? Is a 1 degree or even .5 degree drop in difference commonly indicative?

It's much bigger than that.

So you might have 10 degrees difference from the floor to the ceiling. But when I was doing my sill plate. I had spots that were ~30-50 degrees, and the basement temp was ~60. So you are looking for a minimum 5-10 degree delta when moving the laser horizontally.

Helps to do on a very hot or very cold day.

Edit**

I also insulated my attic, the underside of the decking was close to 100, maybe higher on a hot July day. The ambient temp might have been 85. So even when its hot you can find the spots. Mine was more just finding the gaps in the insulation before I put up the drywall. When the studs are perfect 16 on center the insulation is great. However they often are not 16 on center and you have gaps that need filled.


« Last Edit: November 04, 2021, 12:20:48 PM by Jon Bon »

NaN

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Re: Thermal imaging diy?
« Reply #16 on: November 11, 2021, 06:29:55 AM »
Yes, you need a temperature gradient to create Q, which will highlight the leaks. That's just physics! Q=U*A*ΔT (even MMM had this formula in a blog post). The higher the ΔT the higher the abilities to resolve different U values when A is not changing.

I think the 'laser' thermometer has the same issue with spot size averaging. At least that is what mine from home depot says on it.


Present Muse

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Re: Thermal imaging diy?
« Reply #17 on: December 22, 2021, 09:36:52 PM »
I bought one of these back in late 2016 (the iPhone model).  It was pretty useful for us in finding missing insulation in our ceiling after a remodel.  I took a picture of the ceiling and the interior wall only.  The image showed dark spots in the ceiling where we had missing insulation.  We had a discussion with our contractor after we discovered this and he ended up putting in more insulation afterwards.  I wasn't super happy to discover this and we've since stopped working with that contractor, but that's a different story.

As others have mentioned, it's best to use this when the temperature differences are greater.  I don't recall the temperatures when I took the picture, but it was likely 30 degrees cooler outside than inside, which made it easier to see the missing insulation.  Another feature that I've found helpful - displaying a cross-hair like UI which shows the numeric temperature value.  I think this feature is similar to how the trigger grip ones work, but with this model you also get a heat map image.

I would buy it again.

BDWW

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Re: Thermal imaging diy?
« Reply #18 on: December 23, 2021, 01:55:04 PM »
My understanding is that the lower tier phone ones, and even the cheaper ($500+) consumer ones are generally not very useful.

My dad was a (just retired) maintenance foreman for a mining company. They use FLIRs all the time in their operation for identifying failing motor bearings, hot transformers, etc. He has attended several industry training sessions over the years, and was able to borrow one of his work cameras and bring it home for the weekend. Those units are $25k+ and are much higher resolution(IR sensor resolution) and precise (+- temp differential).  But even with them you need a fair amount of experience to be able to interpret what you're looking at. Things like tracing water leakage is pretty tricky.

You can use the cheaper units for basic insulation and air leakage, but the key is you need have as high a delta between the outside temp and inside temp as possible.  i.e. very cold winter or very hot summer, to be able to reliably see problem areas. Some of the most useful areas of application are the most tricky even then.  Windows(glass) block IR, and often they're a big source of air leakage. So it's hard to tell with a low resolution unit where/if there's a problem there.

I've been watching them for years, and I keep hoping the decent units come down to reasonable prices, but haven't found one that meets the right price to performance for my budget yet.