How does a central heating work, relating to Efficiency

Will_C · Nov 8, 2012

Lately i have been doing some reading up on what is the best way to tun my central heating system but i have little understanding on how the boiler heats the water and how much gas it uses and does it vary the amount of gas it uses or is it just constant. I live in brand new house so believe it has a modern condenser boiler.

I used to use my heating in bursts say an hour or 2 at a time but i found out this is probably the worst thing to do. I now have it on constant with it just going off when it reaches the temperature on the thermostat when i am at home, so it now seems to come on less often for shorter periods of time once the house is up to temperature.

I recently read elsewhere that if all your radiators have TCV's which mine do except one in the hallway near the thermostat then you should use these to control the temperature not the main thermostat, but this would mean my boiler being on constant. Does the boiler vary the gas rate with water flow ?

Another question is i have some radiators turned off how does this save any energy, how does it use less gas by having some radiators off when the boiler is running regardless ?

Thanks for any replies just trying to get my head round it, too much time on my hands i guess !

Simon F · Nov 8, 2012

a modern boiler will regulate the amount of gas being used to give enough heat for the demand. so if all the radiators are cold the boiler will provide more gas than when they are up to temperature.
If a room is closed off and the radiator is turned off then the boiler does not need to supply heat to it, therefore saving energy. that's easy to understand if you think of a big house compared to a small one, which takes more money to keep warm the house with 4 radiators or the house with 24 radiators?? (off course there are other factors such as heat loss)
you should set the TRV'S to the temperature you require for each room, if it goes up to 5, then 3 will generally be around 21 centigrade.
the room stat in your hall should be set to your comfort level lets say 21 degrees, then when that temperature is reached at the stat the boiler will turn off.

Will_C · Nov 8, 2012

Thats pretty much what i do now, i live in a 3 storey house so the rooms at the top we don't use that often so have the radiators turned down low but not off and the rest at around level 3, main stat at 22.