Gas - Is this right?

Max68

Frightening if it is.  Managed to keep the heating generally off recently and whilst not having a smart meter for the last year I have been taking manual readings each day to keep a bit of a record.  Got in tonight and it was very chilly at 16c so decided to put the heating on to bring it up to 17c.  I've got an Imperial Meter so took a reading before I put the heating on and it showed 6474 (white numbers) 68 (red numbers).  A mere half an hour later it had got up to 17c so turned it off and looked at the meter again and it had turned to 6474  95.  Now not sure what you call the red numbers, although obviously I know as soon as it hits 00 the white reading will turn to 6475, but an increase of 28 for a mere half an hour, is that right?  Would I be better off leaving the stat at say 17c rather than letting it get too cold and then blasting it as obviously the boiler is working harder I assume if you do it that way?  Never really looked at it before but that meter doesn't half go round quick when it's on, frightening.

jbuchanangb

Imperial gas meters read in cubic feet. The reading you give to the supplier is from the white numbers, that is hundreds of cubic feet. So in half an hour your reading has gone from 6474 to 6474, for meter reading purposes, you used no gas. Half an hour is not representative of anything. The shortest period that makes any sense is 24 hours. You should set the thermostat at a temperature that you are comfortable with. You are charged for gas in kWH which is derived from your hundreds of cubic feet by a complicated formula, shown on your gas bill. 100 cubic feet is about 32kWh.

Astria

Cold pipework and cold house typically means the boiler will be working at near maximum and so using a lot of gas.

Once everything is upto temperature, the amount of gas used is a lot less unless you have a 30 year old boiler which doesn't modulate and is a simple gas on/off.

Most people will say that there's no point heating an empty house, as a hotter house loses temperature quicker and so you are wasting money.

When you say imperial, do you mean the units are measured in m3 ? should say next to the numbers.

[Deleted User]

Max68 said:

I've got an Imperial Meter so took a reading before I put the heating on and it showed 6474 (white numbers) 68 (red numbers).  A mere half an hour later it had got up to 17c so turned it off and looked at the meter again and it had turned to 6474  95.  Now not sure what you call the red numbers, although obviously I know as soon as it hits 00 the white reading will turn to 6475, but an increase of 28 for a mere half an hour, is that right?  

The red numbers are "after the decimal point" (not actually, but it'll do).  That's 0.28 meter units.  Or 9kWh (ish).

Given that your boiler is probably at least 20kW - using 9kWh in the first half an hour that it's turned on seems sensible, doesn't it?

And no, the second decimal place of a meter going around fast when something big is turned on shouldn't be particularly frightening.  It's like only watching the 1p dial on a petrol pump.

[Deleted User]

Hi,

here's a wee gadget for you to CONVERT.

Rodders53

Imperial meter = white numbers are hundreds of cubic feet  647400 cubic feet the 647500 when it flips over.  So the red numbers are 10s of cu ft and cu ft.

You therefore used 28 cu ft in 30 minutes...  as 100 cu ft  of gas is approx 32 kWh of energy we can state you have used 28 x 0.32 kWh = 9 kWh (at circa 10p / kWh)?   Which likely means your boiler is 18kW output.

Any boiler will work hardest initially to heat up a cold system and get all the circulating water up to the set temperature.  Once that happens it will cycle on/off to maintain the temperature (and modern boilers can 'modulate' the heating flames to be smaller = lower heat out and less gas needed).

Your use was under £1 for that half hour 'blast', but the warm radiators and pipework would continue to give off heat into the rooms until the water cooled down again.

Does your electric meter have a spinny disc - those were really scary if you put on the electric oven and grill together !!!

Max68

Thanks all.  Thankfully the electricity meter is a digital one.  My boiler is a 22-year-old Potterton Suprima.  I'm doing things by the mobile thermostat box at the moment as the heating on/off/auto button on the Danfoss box in the airing cupboard doesn't work anymore and can't afford a new one, so managed to get it to stay "on" and use the thermostat to adjust.  So in a nutshell I would be better off leaving the thermostat at say 17c rather than leaving it low then turning it back up when needed?

ariarnia

it depends what you mean by better off.

what matters is when you need the heat.

if you are out of the house every day from 8 until 6 then thats' a long time when you are heating (and paying to heat) an empty house. probably more than it would cost for an hour of the boiler running full pelt to heat the house back to temp.

in that case a lot of people might turn the thermostat down to 15 when they go out or go to bed so its not 'cold' when there up and about but the temp will drop. 

but if your only out of the house for an hour or 2 then the temp of the house wont drop much so it wont cost much to keep the thermostat on (it might not cost any/much more than turning it down low because the boiler might not come on in that time anyway).

so in that case only you can decide if the time it takes for the house to warm up when you get in is worth the cost of keeping it warm for you. 

[Deleted User]

Hi,

Rodders53 said:

Imperial meter = white numbers are hundreds of cubic feet  647400 cubic feet the 647500 when it flips over.  So the red numbers are 10s of cu ft and cu ft.

You therefore used 28 cu ft in 30 minutes...  as 100 cu ft  of gas is approx 32 kWh of energy we can state you have used 28 x 0.32 kWh = 9 kWh (at circa 10p / kWh)?   Which likely means your boiler is 18kW output.

Any boiler will work hardest initially to heat up a cold system and get all the circulating water up to the set temperature.  Once that happens it will cycle on/off to maintain the temperature (and modern boilers can 'modulate' the heating flames to be smaller = lower heat out and less gas needed).

Your use was under £1 for that half hour 'blast', but the warm radiators and pipework would continue to give off heat into the rooms until the water cooled down again.

Does your electric meter have a spinny disc - those were really scary if you put on the electric oven and grill together !!!

I would've expressed it differently,

The white numbers are thousands/hundreds/tens/ones, the red numbers are one tenth and one hundredth.

So, 6474.95 minus 6474.68 = 0000.27 of a cubic foot,

then, 0000.27 x 32kWH = 8.64 kWh at, say 10p = 86.4p.

Comes to much the same though.

It won't continue at that rate as once house is heated up will be much less.

[Deleted User]

frugalmacdugal said:

Hi,

Rodders53 said:

Imperial meter = white numbers are hundreds of cubic feet  647400 cubic feet the 647500 when it flips over.  So the red numbers are 10s of cu ft and cu ft.

You therefore used 28 cu ft in 30 minutes...  as 100 cu ft  of gas is approx 32 kWh of energy we can state you have used 28 x 0.32 kWh = 9 kWh (at circa 10p / kWh)?   Which likely means your boiler is 18kW output.

Any boiler will work hardest initially to heat up a cold system and get all the circulating water up to the set temperature.  Once that happens it will cycle on/off to maintain the temperature (and modern boilers can 'modulate' the heating flames to be smaller = lower heat out and less gas needed).

Your use was under £1 for that half hour 'blast', but the warm radiators and pipework would continue to give off heat into the rooms until the water cooled down again.

Does your electric meter have a spinny disc - those were really scary if you put on the electric oven and grill together !!!

I would've expressed it differently,

The white numbers are thousands/hundreds/tens/ones, the red numbers are one tenth and one hundredth.

So, 6474.95 minus 6474.68 = 0000.27 of a cubic foot.

One tenth and one hundredth of a hundred cubic feet.

So 0.27 of a hundred cubic feet.

[Deleted User]

Hi,

no, it's 0.27 of 1 cubic foot, 1.27 is 1 cubic foot + 0.27 of a cubic foot.

£1.27 is £1.00 + 0.27p.