British gas units/tarrif and Central heating controls.

roxy28

First question
I am on standard tarrif, do the cost of units always work out the same.
Example from last bill, 4 units used = cost £2.04.
That was 44.76 kwh x 4.560p
So working that out in my mind 8 units a day = £4.08p. If thats the wrong way it works please tell me.

Also which of the cental heating controls has the biggest increase in cost.
ie bumping up the boiler temp , upping the hall thermostat, or turning the radiator valves up to max setting.

Any help please.

Bluebirdman_of_Alcathays

Yes, since two tiered tariffs were abolished all units will cost the same. Energy bills now consist of one unit cost for every KWh of energy, and a standing charge of x p/day.

Why are you on standard tariff? It's never a supplier's cheapest.

Cardew

roxy28 wrote: »

Also which of the cental heating controls has the biggest increase in cost.
ie bumping up the boiler temp , upping the hall thermostat, or turning the radiator valves up to max setting.

Any help please.

No 'one size fits all' answer I am afraid.


1. If you have an old non-condensing boiler, the boiler temperature will make very little difference in efficiency - and hence cost.


With a condensing boiler, the lower the temperature is generally better as the boiler is more likely to stay in 'condensing mode.


2. However the air temperature in the various rooms in the house have the biggest effect on running costs. It really doesn't matter what combination of wall thermostat and radiator valve(TRV) you use. The higher the temperature the greater the cost.


N.B. If you have the hall thermostat too low, altering the TRV will have no effect.

roxy28

Cardew wrote: »

No 'one size fits all' answer I am afraid.


1. If you have an old non-condensing boiler, the boiler temperature will make very little difference in efficiency - and hence cost.


With a condensing boiler, the lower the temperature is generally better as the boiler is more likely to stay in 'condensing mode.


2. However the air temperature in the various rooms in the house have the biggest effect on running costs. It really doesn't matter what combination of wall thermostat and radiator valve(TRV) you use. The higher the temperature the greater the cost.


N.B. If you have the hall thermostat too low, altering the TRV will have no effect.

Ok thanks.
Its a combi boiler.
Boiler temp control is 30c min, 80c max , mine is 50 at the minute is that ok?

The house really does not get as warm as i would like, even though the rads get hot.

Rads are on 4 the range is 1 to 6 , and the hall thermostat is set 21c

roxy28

Bluebirdman_of_Alcathays wrote: »

Why are you on standard tariff? It's never a supplier's cheapest.

Right ok, i thought it was.

Cardew

roxy28 wrote: »

Ok thanks.
Its a combi boiler.
Boiler temp control is 30c min, 80c max , mine is 50 at the minute is that ok?

The house really does not get as warm as i would like, even though the rads get hot.

Rads are on 4 the range is 1 to 6 , and the hall thermostat is set 21c

Are there two temperature controls - one for the hot water to taps and the other for Hot water to radiators?


If the house is not really warm enough then turn up the boiler temperature to say 60C and see if that is sufficient. It will do no harm to even have it at 80C except the radiators will get hot enough to burn young children.


If that control also sets the HW for taps at 80C - then that is hot enough to scald badly - and you will get a very slow flow of water.


The TRV settings on the radiators usually correspond to a range of between 16C to 24C. However they will never reach the higher set temperatures unless the water in the radiators(combined with the size of the radiators) can dissipate sufficient heat.

roxy28

Cardew wrote: »

Are there two temperature controls - one for the hot water to taps and the other for Hot water to radiators?


If the house is not really warm enough then turn up the boiler temperature to say 60C and see if that is sufficient. It will do no harm to even have it at 80C except the radiators will get hot enough to burn young children.


If that control also sets the HW for taps at 80C - then that is hot enough to scald badly - and you will get a very slow flow of water.


The TRV settings on the radiators usually correspond to a range of between 16C to 24C. However they will never reach the higher set temperatures unless the water in the radiators(combined with the size of the radiators) can dissipate sufficient heat.

Yes 2 temperature controls, water to rads 50, and water to the taps is 50 at the minute (max 60 )

If i bump up water to the rads to max at 80 , will that increase costs quite a bit?

Cardew

roxy28 wrote: »

Yes 2 temperature controls, water to rads 50, and water to the taps is 50 at the minute (max 60 )

If i bump up water to the rads to max at 80 , will that increase costs quite a bit?

If you have an old non-condensing boiler then setting the water to 80C will not have a significant effect on costs.


With a modern condensing boiler it will probably be slightly more expensive - but difficult to measure.


However there is no point IMO having CH and the house not warm enough, because the boiler temperature is set too low. You need to increase the temp to say 60C and see how that works; if necessary increase it again.


I take it that the radiators have been bled and are not filled with sludge. They should be hot all over, slightly cooler at bottom.

roxy28

Cardew wrote: »

If you have an old non-condensing boiler then setting the water to 80C will not have a significant effect on costs.


With a modern condensing boiler it will probably be slightly more expensive - but difficult to measure.


However there is no point IMO having CH and the house not warm enough, because the boiler temperature is set too low. You need to increase the temp to say 60C and see how that works; if necessary increase it again.


I take it that the radiators have been bled and are not filled with sludge. They should be hot all over, slightly cooler at bottom.

Yes its a condensing boiler , the rads have been bled and hot all over, sometimes the rads do feel hotter at the top but not massive diffrence.

I know what you mean about no point if temps set too low , but am wary how high settings can mount up costs.

Thanks again.

Cardew

roxy28 wrote: »

I know what you mean about no point if temps set too low , but am wary how high settings can mount up costs.

Thanks again.

The problem is nobody can quantify just how much(if any) it will increase gas costs by increasing water temperature. It depends on getting, and keeping, the boiler in condensing mode and that varies with every house.


Set at 60C there is no reason to think that the boiler won't operate in condensing mode. You might ask why the boiler has the capability to operate at 80C if it was uneconomic.

roxy28

Cardew wrote: »

The problem is nobody can quantify just how much(if any) it will increase gas costs by increasing water temperature. It depends on getting, and keeping, the boiler in condensing mode and that varies with every house.


Set at 60C there is no reason to think that the boiler won't operate in condensing mode. You might ask why the boiler has the capability to operate at 80C if it was uneconomic.

I remember when they put this boiler in , it was summer just gone, so had to have a day off.
When they tested it out it was on for 2 hours , its only when they left that i found they used high settings.

The boiler temp was 80 , the rad valves were at max 6 , and the hall thermostat was set to max 30c.

That used 4 units in the 2 hours.