On Feb 4, 9:17 pm, Dave Fawthrop
wrote:
Has anybody got any figures on the performance of Thermostatic Room Valves?
Settings 0 - 5 = ??? degrees C
open to closed = ??? degrees C
There must be a specification somewhere.

Danfoss RAS-C leaflet says;

frost * 8
I 12
II 16
III 20
IIII 24
I C

I don't think there is a standard.

You won't get precise control throughout the room because, even if the
TRV were operating perfectly, it would take some time for a change in
output to be measureable at all points in the room. It's cheap &
cheerful but good enough for most purposes. To get exact control of
room temperature, you'd need to circulate something like 10 AC/hr
through a convector heater.

Even then, people's perception of comfort involves both humidity &
radiant heat, as well as air temperature. E.G., the kids complain
they're cold in the morning despite room air temperature being 21,
'cos floors and walls are cold. Kids are warm in the evening at the
same air temperature 'cos floors & walls have heated up & so less heat
lost through radiation.