It is to decide between two possibilities for heating of rooms during the absence in the building:
- heating constantly to 20 °C (68 °F) or
- heating 1 hour before coming home with 25 °C (77 °F) with the same effect that the room temperature is 20 °C (68 °F) at 5 p.m.
The following conditions has the example:
No people are at home 9 hours in the time between 8 a.m. and 5 p.m.
The outside temperature is 0 °C (32 °F).
The normal inside temperature shall be 22 °C (72 °F).
The building has a medium insulation, so that the room temperature decrease from 22 °C (72 °F) to 18 °C (65 °F) after 4 hours.
Which method of heating is the best to achieve low energy costs?
Best Answer
The engineering theory is that a greater differential in temperature causes a faster loss of energy, so maintaining a constant temperature is more costly.
This theory was proven by tests of Twin Homes by The Canadian Centre for Housing Technology. Several papers have been written about studies at these homes, here is a rather thorough one https://www.healthyheating.com/downloads/Thermostats/nrcc48361.pdf