Rachael wrote:
I talked to my 'boiler man' about this and he advised that with modern boilers it is indeed much more fuel efficient to get the house up to a comfortable temperature and then leave the thermostat alone. Don't turn it down to turn off the heating. Let it tickle the boiler up and down. Because (of course) it takes less energy to maintain the temperature required than to bring it up to temperature from maybe ten degrees lower.
So my thermostat goes from 20 degrees first thing in the morning to 18 degrees all day, back up to 20 in the evening and no lower than 15 over night. My gas consumption has gone down.
I would question the logic of maintaining the thermostat at 15 , or leaving the boiler on at all overnight.
At nighttime the outside temperature will fall, in wintertime most likely significantly more then the 3 degrees difference between your daytime & night time target temperature for the house. Therefore the temperature gradient between the internal and external temps will be greater, meaning that the heat loss will be larger , meaning your boiler has to work harder (use more gas ) to replace the lost heat, all the while, presumably, the occupants of the house are being kept warm by bedclothes. It's true the boiler will have to work harder when its turn on in the morning, but it is unlikely to be the same amount of energy as leaving it on for eight hours a night, even at 15. IMO.
Of course, if you have a super insulated home then the above is less critical as the heat losses will be vastly reduced.
