Central Heating

[fourteen85]

If I reduce or turn off ,say, half the radiators in the house ,does the boiler work any less and does it cost any less in electricity to run 50% of the rads? just intrigued as the water still passes through the radiator to get to the next one

[murraymints]

If you turn off valve on radiator then it will be bypassed and remain cold....boiler will still operate at full power but as it has a shorter circuit to complete water will stay hotter for longer so you will save as it will not fire up so often.....I think....builder will correct me if I'm wrong !

[murraymints]

Similarly if you reduce individual controls...Will not fire up as often....but builder is expert, he'll be along later so keep checking....

[fourteen85]

Thanks for that , all sounds sensible

[bhg481]

Murraymints is dead right. Your radiators are in parallel with each other, just like the light bulbs in your house. If you turn off a light it saves power; if you turn off a radiator it saves power. Unless you have an electric boiler it won't save any electricity because the electric bits of your current boiler are just for the controls. It WILL save you gas/oil as you won't be using as much to heat the water.

[fourteen85]

BHG will it not use electricity for a pump to send the water around the system?

[bhg481]

Fourteen - yes, but the amount used for that (and the controls) is trivial compared with the fuel used for heating the water - we're probably talking pence per year compared with £100s a year for fuel.

[murraymints]

14 ..as above you save on whatever fuel is heating water.....power for pump and firing is minimal....

[fourteen85]

Ok , thanks for your replies

[Old_Jim]

The boiler heats the water to a set temperature. If the water were to stay at that temperature, the boiler would stay off. The boiler fires up when the water cools down. The more radiators you have on, the faster the water cools and the more time the boiler has to stay on to keep it up to temperature.

It's actually more complicated than that. The amount of energy that the boiler has to put into the system is the amount actually lost by the building. If you had perfect insulation, the heating would warm the house up to the required temperature and never come on again. However, heat is lost through the roof, walls and floor. The greater the temperature difference between inside and outside the house, the more energy escapes. Having all the house hot means that more energy is lost through leakage to the outside world. Having only part of the house hot means less energy is lost and you use less.

You mention electricity. Do you have an electric powered boiler? If the boiler works with oil or gas, electricity is only used for the pump and ignition. The longer the pump is running, the more electricity you use, but that depends on the use cycle of the boiler and pump.

[The Builder]

Nothing much to add to all the good replies.

Simply, one 22mm pipe leaves the boiler (the "Flow"), runs around the house and back to the boiler (the "Return").

All the rads are individually branched off this circuit. Any rad can be separately turned off. The fewer the rads, the fewer the heat losses, so you save money.

Your roomstat controls the pump. When the pump is switched on it takes very little power. Not worth considering.

To save even more, since only a few rads are on, you could turn your heating control thermostat down on the boiler. It's usually set at around 75%, but with reduced losses you may even be able to set this lower. Perhaps no lower than 50% though, as efficiency would be greatly affected.

[fourteen85]

Thank you all once again

[BRIGHT SPARK]

It will only save you money if the rads you turn off are in isolated rooms with the doors closed.Otherwise the rest of the system will work harder to heat the isolated rooms.