gas usage doubled to 24,000kwh

[Susan H]

Hi i wonder if anybody can help with my query, the only gas appliance i have is a ideal Mexico super cf455 boiler, historically my gas usage was 12kwatts a year it is now double that figure at around 24,000 kwh, the boiler is only on for very short amounts of time as in not left on all day/night, i have left it off for 24 hours and checked the meter, no gas was used. the boiler seems to be using 1.7 units which i calculate as 53 kwh in one hour of run time. i have spoken the the engineer who services the boiler and he said the unit would not burn double the the amount of gas and thinks it might be the gas meter, any help would be much appreciated. there is no gas cooking.
thanks

 

[Last Plumber]

Where have you got your figures from?
The first is in Kw the second in Kwh. We need to clear up what you're saying first of all so we are all in the same units.

The 1.7 units:
Is that meters cubed? If it is then it doesn't add up to 54 Kwh.

If you can clarify those things, we can help more.

 

[Susan H]

Where have you got your figures from?
The first is in Kw the second in Kwh. We need to clear up what you're saying first of all so we are all in the same units.

The 1.7 units:
Is that meters cubed? If it is then it doesn't add up to 54 Kwh.

If you can clarify those things, we can help more.

hi,
thanks for reply.
a 45 minutes example from day before
reading before on 4228.664 M3
reading after 4229.941 M3
gas boiler only on . no cooking.
thanks

 

[Last Plumber]

hi,
thanks for reply.
a 45 minutes example from day before
reading before on 4228.664 M3
reading after 4229.941 M3
gas boiler only on . no cooking.
thanks

If we use that and calculate the Kwh, it is 19.298. That's using the correction factor/calorific value and so on that I use currently.

I thought you only had the one gas appliance?

 

[Last Plumber]

If that was from cold by the way, it looks to be using the amount I would expect too.

 

[Basher]

I believe the boiler has a max output of 16kW and its efficiency is said to be 78% so I agree it could consume 19kW in an hour flat out

 

[Chuck]

hi,
thanks for reply.
a 45 minutes example from day before
reading before on 4228.664 M3
reading after 4229.941 M3
gas boiler only on . no cooking.
thanks

So you are using 1.28 m^3 in 45 minutes, which is 1.7m^3 per hour. That's about 19.3kWhr per hour.

If you have the boiler on at that rate for five hours a day for the four cold months of the year you'd use 11,740 kW hr.

This year has been a bit colder (in terms of degree days) than last year so your consumption may well be up by, say, 20% or so because of the weather this season.

Where did the '24,000 kwh' figure come from?

 

[Susan H]

If we use that and calculate the Kwh, it is 19.298. That's using the correction factor/calorific value and so on that I use currently.

I thought you only had the one gas appliance?

sorry, yes only that gas appliance. Electric oven and hob.
does that usage sound alot for 45 mins for that boiler?

I had used following reading 4229.941 -4228.664 = 1.277 for 45 mins
or 1.7 units per hour
1.7 units x 2.8 x 1.02264 x39.1 /3.6 = 52.86 kwh
calcs from Octopus energy

thanks

 

[Susan H]

So you are using 1.28 m^3 in 45 minutes, which is 1.7m^3 per hour. That's about 19.3kWhr per hour.

If you have the boiler on at that rate for five hours a day for the four cold months of the year you'd use 11,740 kW hr.

This year has been a bit colder (in terms of degree days) than last year so your consumption may well be up by, say, 20% or so because of the weather this season.

Where did the '24,000 kwh' figure come from?

 

[Basher]

sorry, yes only that gas appliance. Electric oven and hob.
does that usage sound alot for 45 mins for that boiler?

I had used following reading 4229.941 -4228.664 = 1.277 for 45 mins
or 1.7 units per hour
1.7 units x 2.8 x 1.02264 x39.1 /3.6 = 52.86 kwh
calcs from Octopus energy

thanks

I think that calculation is for an imperial meter, but you have a metric meter. it should come out at 19kWh ish according to an online calculator I used!

 

[Susan H]

i had always worked around 12,000.
24,000 is the figures on my bills consumed.
i have spent ages going through them and adding up in a spreadsheet.
it went wrong in 2020 when they put in a weird estimate which suggested I would use 85,000 kwh per year!
so the "estimate" has been wrong ever since so difficult to gauge plus increased unit rates
however, i have now been through my "actual use" and it is adding up to over 24,000KWH.

 

[Susan H]

i had always worked around 12,000.
24,000 is the figures on my bills consumed.
i have spent ages going through them and adding up in a spreadsheet.
it went wrong in 2020 when they put in a weird estimate which suggested I would use 85,000 kwh per year!
so the "estimate" has been wrong ever since so difficult to gauge plus increased unit rates
however, i have now been through my "actual use" and it is adding up to over 24,000KWH.

hi
what is the digital meter calculation please.

 

[Chuck]

1.7 units x 2.8 x 1.02264 x39.1 /3.6 = 52.86 kwh

The factor '2.8' should not be in there. Maybe your boiler was running for 2.8 hours on the day in question? i.e. 52.86kWhr is the average usage over one day?

 

[Last Plumber]

sorry, yes only that gas appliance. Electric oven and hob.
does that usage sound alot for 45 mins for that boiler?

I had used following reading 4229.941 -4228.664 = 1.277 for 45 mins
or 1.7 units per hour
1.7 units x 2.8 x 1.02264 x39.1 /3.6 = 52.86 kwh
calcs from Octopus energy

thanks

I don't know what that 2.8 figure is for?

If you are converting from an imperial meter which measures cubic feet, then the conversion is not 2.8, it would be
0.0283168 (0.028 for short/ease).

 

[Last Plumber]

I think you have maybe written the calculation down incorrectly?

 

[Last Plumber]

So it used 0.52Kwh?
Agree?

 

[Last Plumber]

Maybe they have taken a reading thinking it was meters when in fact it is feet?

 

[Last Plumber]

There are 35.31 Cu feet in a Cu Meter

 

[Susan H]

hi
what is the digital meter calculation please.

someone may have hit the nail on the head!

bill says for 39 days
consumption 149.6 units (100s of ft3)

then there is the calculation 149.6 x 2.83 x 1.02264 x39.1 = 4701.2
4701.2 kwh used

but if my meter is digital (reading for example 04229.941m3)
does this mean they are converting a m3 reading which is already in m3 ? do you think?

 

[Chuck]

does this mean they are converting a m3 reading which is already in m3 ? do you think?

That explanation fits the information you have given us.

 

[Susan H]

That explanation fits the information you have given us.

thanks all
this has been really helpful