I think generally 17 degrees is too cold in the winter. Just now, for me, it's about right. The man who built our house has several times gone around checking our thermostats to make sure they are not above 16 degrees
as apparently this will dry out the house and cause cracks. I actually don't give a flying feck about cracks - I care about keeping my children and me warm. So when it gets colder outside, the thermostat will go up.
To me, 16 degrees is the temperature in my car when I have the air con on in blazing weather. It is not warm enough to heat a house when it is cold outside.
I grew up in a house where ice used to form on my glass of water by my bedside, so damned if I am going to suffer being cold now. I humour the builder and go round switching the thermostats to his required temperature prior to his visits. Just so I don't get him telling me to just put another jumper on when it is -7 outside (as he did last winter).