There are two schools of thought when it comes to heating a home: have the central heating going on and off with a timer, or set the temperature for the house and keep the central heating on for constant and consistent warmth. Those with the latter opinion say that it is more efficient to have a level of warmth at all times rather than to let everything grow cold and have to reheat. With double glazing it is probably true that having your home set at a steady, consistent temperature will give you both a comfortable environment at all times and a level of efficiency due to the minimal heat loss. It’s important that you aren’t losing heat elsewhere, but modern double-glazing with its special exterior glass and the highly efficient gas used in the gap between the two glass panes confers excellent insulation. Whereas homes once lost a lot of heat through windows, now these are likely to be the big areas where heat loss is lowest.
You might use the timer to reduce the overall temperature setting over night, or when everyone is out, but allowing a house to lose heat and become chill is also likely to increase humidity levels and lead to an increase in condensation. A damp environment is harder to bring up to heat and takes more energy.
We always have our temperature setting at about 20’C, which we find comfortable and not too warm, and we leave it there, unless we go away, then we drop it to about 18’C, which would be a bit cool for comfortable living but nevertheless does not lead to the house growing chill.
Whether you keep your internal doors open or closed is another factor, affecting airflow and heat distribution. If you have a property with a south-facing aspect that benefits from solar gain on sunny cold days, it’s a good policy to encourage distribution of this free warmth by keeping doors open and allowing circulation.