Lowering temperature of water circulating through radiators. Will it save money?

_Jem_

RelievedSheff said:

st999 said:

So if the property takes longer to heat up that means the boiler will be on longer so I would think you wouldn't save much money.

No not with a modern condensing boiler as the boiler won't be fired up using gas for the whole period.

With the boiler I had in a poor insulated home, it did cost more in electricity because the boiler was on.
Swings and roundabouts comes to mind. 

RelievedSheff

_Jem_ said:

RelievedSheff said:

st999 said:

So if the property takes longer to heat up that means the boiler will be on longer so I would think you wouldn't save much money.

No not with a modern condensing boiler as the boiler won't be fired up using gas for the whole period.

With the boiler I had in a poor insulated home, it did cost more in electricity because the boiler was on.
Swings and roundabouts comes to mind. 

Which is why I and several others have said that it varies from house to house and person to person.

st999

If I put 3 cupfuls of water in a pot on a gas ring at full setting it takes 5 minutes for the water to boil.
If I turn the gas down to minimum it never boils.

adonis

I don't know where the op lives but why do you have the heating on in July when it is hot unless I have missed something.

_Jem_

RelievedSheff said:

_Jem_ said:

RelievedSheff said:

st999 said:

So if the property takes longer to heat up that means the boiler will be on longer so I would think you wouldn't save much money.

No not with a modern condensing boiler as the boiler won't be fired up using gas for the whole period.

With the boiler I had in a poor insulated home, it did cost more in electricity because the boiler was on.
Swings and roundabouts comes to mind. 

Which is why I and several others have said that it varies from house to house and person to person.

And the serveral other would also be me as stated on a previous post I made👍

matelodave

st999 said:

If I put 3 cupfuls of water in a pot on a gas ring at full setting it takes 5 minutes for the water to boil.
If I turn the gas down to minimum it never boils.

Its the same with a hous - if the heat loss is greater than the heat input then you'll never get it warm enough so you need more heat that that which is being lost to get it hot but once it's at the temperature that you require then then you turn it down to balance the heat loss again. 

If you use your gas stove analogy you can turn the heat up to full blast and waste a lot of heat because it doesn't all get absorbed all at once, but once it's boiling you can either turn the heat down to let it simmer or turn it off and then give it another full blast five or ten minutes later to get it back up to temperature (and as a consequence lose a lot more heat around the edges). The ideal situation is as Cardew describes  - weather compensation - where the boiler temperature is adjusted to suit the anticipated heat loss. A lower temperature when its warmer and a higher one when it colder outside.

It really is a case doing you own measurements of energy consumed against varying flow temperatures and how long you are prepared to wait for the place to reheat taking into account the inside and out side temperatures as well. Intuitively it does seem like blasting the boiler for a couple of hours instead of letting it idle all day seem to be better. However as Cardew says - you use a lot less fuel driving at 50mph than you do at 80mph - you still get the to same destination and one will be quicker but the cost will vary significantly

Gerry1

matelodave said:

The ideal situation is as Cardew describes  - weather compensation - where the boiler temperature is adjusted to suit the anticipated heat loss. A lower temperature when its warmer and a higher one when it colder outside.

I'd have thought that the main function of weather compensation sensor was to start the boiler earlier in the morning when it's very cold so that the house reaches always the desired temperature at the correct time.  Relying only on a timer means that energy would be wasted on more temperate days because boiler would start earlier than needed.

st999

In the winter my heating is set to come on at 07:45 and I usually get up just after 08:00 and because the radiators are hot even though the temperature is not up to the set 21 deg C the house feels warm enough.
It takes about 45minutes to an hour before the boiler switches off.
Another thing about water temperature, I had my hot water set just hand hot, never needed to run cold water into the basin when doing the dishes and after a while my sink drain would smell and I had to pour bleach down it.
I raised the temperature to 50 deg and have never had to pour bleach down the drain since and according to my smart meter I am only using 2 kWs more gas a day.
Cheaper than the cost of the bleach I was pouring down the drain and I get a more powerful shower.

Cardew

Gerry1 said:

matelodave said:

The ideal situation is as Cardew describes  - weather compensation - where the boiler temperature is adjusted to suit the anticipated heat loss. A lower temperature when its warmer and a higher one when it colder outside.

I'd have thought that the main function of weather compensation sensor was to start the boiler earlier in the morning when it's very cold so that the house reaches always the desired temperature at the correct time.  Relying only on a timer means that energy would be wasted on more temperate days because boiler would start earlier than needed.

Not so!

The Central Heating timer determines when the boiler comes on. The weather compensation sensor has no effect on those times. i.e. it doesn't matter if it is 10C outside or minus 10C the boiler doesn't turn on until the CH timer 'allows'* the boiler to operate. Then if the outside temperature is 10C the water to radiators will at a much lower temperature than it would be if the outside temperature is minus 10C.

  * some people set their CH system so that if the room temperature drops below a certain level(e.g. 15C) then the boiler will switch on; but that is a function of the internal thermostat NOT the weather compensation sensor.

Talldave

If you use a programmable thermostat with optimum start, it adapts to the seasonal temperature by adjusting the start time based on recent cycles of the programme. Although I've not used one, I believe some are available with outside temperature sensors to improve the accuracy of the optimum start algorithm.