"Ed Sirett" wrote
As with all these matters there is a mixture of personal preferences,
regulations, common practice and existing arrangements to be taken into
account.

Very often living rooms do have an additional source of heat (various
forms of display or real fires, say). Also the living room might be one
that is subject to a substantial solar gain. [Imagine -5C outside and a
totally cloudless sky with the sun nearly horizontal straight in through
the large patio window?]

I totally agree with Christian about the need to make sure that the area
governed by the thermostat is a bit slower than the rest of the house/zone
to warm up.

A big advantage is that the heating control in the hall is right to hand
whe you come in. (I think it's "Luddite" to still be using separate time
and temperature controls! Ferreting around in utility cupboard or under
kitchen units to switch the heating on.

Sometimes the wiring is already in place to the hallway.

My MIL, aged 90, has the thermostat in the living room and a display gas
fire, the rest of the house gets cold when the fire is in use (which she
likes to use).


Another thing to consider, apart from additional heating appliances and
solar gain, is other heating sources. Each warm body is reckoned to be 300W,
then you've got all the lighting in a lounge, not to mention TVs etc. All
these can conspire to make the lounge warmer and the rest of the house cold.


Steve S