In my last video, I used a FLIR thermal imaging camera to observe the spread of heat on an aerated
concrete block. I was so impressed with this gadget that I felt it deserved a dedicated video.
So, today we’re going to compare this FLIR ONE Gen 3 camera that costs $200 on Amazon with this FLIR
ONE Pro camera that costs $375. Links to both are in the description below. They measure 2.7x1.3x0.6
inches. The Gen 3 camera weighs 34.5 g while the Pro camera weighs 36.5g.
I bought the ios versions, but you can find android versions of both products.
They connect to iPhones with an adjustable male lightning port that can be moved up or down to
account for the thickness of phone cases. The cameras run on a battery that lasts about 40
minutes and takes an hour to fully charge. Every package comes with a usb type c charging cable
and a padded carrying pouch. To use the FLIR thermal camera, plug it into your charging port
and tighten the dial. Install the FLIR ONE app on your phone and then open it. Hit the power button
at the bottom of the thermal camera and wait a few seconds for it to connect and calibrate.
Let’s first take a look at this GE natural gas water heater inside my home. Footage from the
cheaper Gen 3 camera is on the left and the more expensive Pro camera is on the right. The exhaust
vent through the ceiling glows bright yellow since it is hotter than the surrounding walls which are
bluish-purple. The pipes carrying the hot water and the combustion chamber at the bottom of the
water heater also glow bright yellow. These gadgets are pretty incredible. But,
we don’t want to just look at pretty pictures, we want to figure out how they work, right? So,
FLIR is an acronym for forward looking infrared camera. Teledyne Technologies, who owns FLIR,
sells devices for surveillance, border and maritime patrol, search and rescue, etc.
Regular daylight cameras and the human eye both capture visible light energy, 380-760 nm.
Visible light bounces off objects and hits a detector like a digital camera sensor,
a piece of film or our retina. These detectors turn light into an image. On the other hand,
thermal imaging cameras detect infrared energy or heat, 760 nm to 1 mm. All objects, whether cold
or hot, emit infrared energy. Detectors like the FLIR cameras turn this energy into images. Both
the Gen 3 and the Pro devices have 2 cameras - one for visible light and another for infrared.
The images are overlaid with MSX or Multi-spectral Dynamic Imaging Technology. This enhances thermal
images and makes them more recognizable. The Gen 3 camera can measure temperatures
from -20C to 120C or -4 to 248F. The Pro camera can measure -20C to 400C or -4F to 752F. That’s
3 times higher! For residential applications, the cheaper Gen3 camera should suffice. The Pro camera
is more useful for industrial applications, like measuring boilers, kilns or furnaces.
To see the change in temperature on the cameras,
I ran hot water down this sink for a couple of minutes. You can see the P trap and sink
rapidly change color from a cooler purple at 70F to bright yellow at over 80F.
Images on the Gen 3 camera are 80x60 pixels, while the Pro version is 160x120 pixels,
4 times better. Higher resolutions means that each image contains more information, and more accurate
measurements. These resolutions seem very low compared to monitors and phones which have 4k
resolution. The reason is that thermal detectors need to sense energy that has much larger
wavelengths than visible light, so each sensor element has to be significantly larger.
As a result, a thermal camera has a much lower resolution than visible light sensors.
I captured my uninsulated attic ladder with both cameras. As you can tell, footage on the
Gen 3 camera isn’t as sharp as the Pro camera which has 4 times the number of pixels.
Related to resolution is spectral range which is the range of wavelengths that the sensor in the
camera detects. Both cameras are long wave with a spectral range of 8-14 micrometers.
But their pixel size is different. The Gen 3 has a pixel size 17 um
while the Pro has a pixel size of 12um so it can fit more pixels in an image. I was curious to see
the heat loss through the ceiling in my dining room since it’s the hottest room in my house.
Insulation on the sloped portion is so poor, you can see the outline of each 2x4 wood stud.
The interior walls and ceilings didn’t have any hot patches though.
Thermal sensitivity or Noise Equivalent Temperature Difference (NETD) describes
the smallest temperature difference you can see
with the camera. The lower the number, the better the thermal sensitivity of the
infrared system. The Gen 3 camera has a thermal sensitivity of 150mK, while the Pro is 70 mK.
This was obvious when looking at a hot ceiling fan that’s next to a cold air vent. The color
gradient on the Gen 3 footage on the left isn’t as detailed as the Pro footage on the right.
If you use the thermal camera in front of a reflective surface like a mirror,
you will see objects in front of it, rather than measure the temperature of the mirror itself. This
is because of the emissivity of mirrors, which is a measure of how well an object radiates
heat. An emissivity value of 0 is a perfect mirror that reflects all heat. An emissivity value of 1
is a blackbody that perfectly absorbs all heat. Both cameras have a fixed focus of 15cm to
infinity, so they are always in focus. You do not need to manually adjust them.
However, they have a relatively slow refresh rate of 8.7 Hz, which can make the video
seem laggy and stuttering. This is a government and trade regulation,
it’s not something FLIR can control. I love that FLIR is making professional
technology available to the masses. These are going to be very useful during my home remodel
because it’s going to help me find trouble spots.
For example, I found this one weird hot spot on the ceiling of the master bedroom.
I just can’t figure out what it is. There are no roof penetrations, no vents or ceiling fans.
I’m going to have to get into the attic and crawl to that area to figure out what’s going on.
Another trouble spot is the attic fan which is controlled by these 2 switches. An incredible
amount of heat seeps through it. I might have to remove it and patch it up or add some removable
insulation. This is a 45 year old home, so I have to accept that it’s not properly sealed
and it’s going to have some issues. However, I can address easy fixes such as replacing attic fans,
attic ladders and the windows. Fortunately, the interior walls seem to be very well insulated.
There’s another thermal camera in between these 2, it’s called the FLIR ONE PRO LT and it costs $269
on Amazon. But it has a lower thermal sensitivity and lower resolution, so you might as well get
the Gen 3. I love the better resolution of the Pro and the temperature range in its live view.
Both the cheaper Gen 3 and the more expensive Pro are excellent devices,
so just buy what fits your budget. Let me know if I should do more product reviews,
and if there are any gadgets you are interested in. I’ll link my Patreon page in the description.
If you can support me, I’d really appreciate it. A big thank you to everyone already supporting me.
Don’t forget to hit the like button and subscribe to my channel. Thanks for watching. See ya.