The measurement is carried out quite fast. I can not really give an opinion on the accuracy geigneter lack comparative measurements; the measurements are however plausible and therefore allow at least an initial evaluation - which usually also sufficient for household use. So I have the impression that the masonry colder in a corner of my apartment is than the rest, can objectify with this device.
A few caveats should be noted: Reflective surfaces are poorly suited, and translucent surfaces will not be "screened", but it is actually measured the surface.
The device should not be exposed to too rapid changes in temperature. Otherwise you can take the device but now in operation.
Can I recommend.