I have been working now 4 months in the field of air conditioning technology. (Mainly buildings and plant conditioners)
We have a Testo 830-T4 but is also very good very expensive. (Measuring range -30 ° C to + 400 ° C)
Now took me time interested whether for a simple IR thermometer is just as good, or whether there are differences.
For one thing is clear, the price one thing. This thermometer costs just scarce 30 (The Testo 170 cost)
On the other hand, of course, the Testo is significantly better protected against damage and shocks of any kind. The cladding is partly made of rubber and should sometimes survive a fall. When TFA Dostmann just only plastic. What personally but does not bother me. (At this price ...)
The hint that you should adapt the measuring equipment to the ambient temperature, is on two packages!
(It really is useful, eventually one would like as accurately as possible measurement results.)
We use the thermometer to the heat pipe to determine. This is very easy with contactless IR thermometers.
The big surprise:
We made about 40 comparative measurements in different installations. (Measuring ranges between -10 ° C and + 90 ° C)
The differences amounted to a maximum of 2 ° C. Usually, the differences were so at 0.5 ° C. I was very surprised indeed. Especially since that is so, that is not necessarily where it maintains a low cost product in hand.
Due to the accuracy and the fact that one here barely has approximately 1/6 of the cost compared to expensive Testo, I can definitely recommend this unit. Price-performance ratio is right here definitely.
How does the device holds in the longer term, I can not judge.
We will continue using it because it is absolutely good for our purposes.
Update December 2014:
And unfortunately, it's a cheap device.
The unit has significantly lost after a few months of accuracy.
On short distances (less than one meter) it holds true in borders and halfway displays reliable readings ...
Everything about it goes out, it is a guessing game. Deviations of more than 10 ° C DIFFERENCE are not uncommon.
Anyone who wants to use the device to measure over longer distances, should not buy here!