Working out Central Heating running cost

dan~_2

Hello, I think I’m going a bit mad trying to work this out.

I do not have a smart meter but I’m interested to see how much it actually costs to run the boiler per hour.

I went to our meter and wrote down the reading, had the boiler on for 2 hours then re-read the meter

1st value 22644.769
2nd value (2hours later) 22646.212

So I have used 2 units and went onto this site https://businessenergy.com/business-gas/gas-bill-calculator

For Metric meter, I typed in 2 (as the number of units used), changed the calorific value to 39.5 (on BG bill) then for units I pay 4.1p per kWh for gas, so I entered 4.1 (not sure if that’s correct?) press calculator and it works out as £0.92.

I think it’s me being stingy thinking it costs an earth to run the heating but £0.92 divided by 2 = £0.46p per hour to run.

That seems way to cheap in my opinion to heat a 4 bed detached house per hour.

Are my calculations correct? Admittedly the house has stuck round 14.5oC all day and only set to 18oC, though when it’s proper winter and the house is at 10oC getting to 18oC takes ages due to the hallway only having a downstairs radiator.

If my calculations are correct when the house gets silly cold I’ll be re-doing another check on that website.

Thanks

Robin9

2 hours will not give you a good picture. The boiler will probably be running flat out - only when it gets to its target temp will it cycle.

Run the heating as you normally would and read the meters weekly.

Don't forget Standing charges and VAT

PS 4.1p is high.

dan~_2

Hello, I didn’t count in standing charge and it’s not a lot and I have to pay it regardless but I did forget about VAT but that’s only going to be small at 5%.

The 4.1p is what we’re locked into with BG until 2021 so nothing I can do about that, when I was looking at the big 6 they were all basically the same, but that’s my fault.

On that website where it says unit rate, I guess I put on 4.1 as my rate?

If it’s correct then I’m very happy, I always thought it costed more to run it which is why I’ve been so stingy with having it on

molerat

1 metric meter unit is approx 11.2 kWh as a rough and quick calculator.

dan~_2

molerat wrote: »

1 metric meter unit is approx 11.2 kWh as a rough and quick calculator.

Would that be in my case of 2 hours be 22.4 x 0.04?

Gerry1

I went to our meter and wrote down the reading, had the boiler on for 2 hours then re-read the meter

That's ridiculously short period to use as the basis for any meaningful calculations. The boiler could have been off for much of that time; its duty cycle will depend on the difference between the outside and inside temperatures and may well have been significantly less than 100%.

1st value 22644.769
2nd value (2hours later) 22646.212

So I have used 2 units

By rounding up you've introduced an error of 38%.

pay 4.1p per kWh for gas

You're paying far too much ! Do the sums and you'll find it's probably worth switching and paying the exit fee.

dan~_2

Gerry1 wrote: »

That's ridiculously short period to use as the basis for any meaningful calculations. The boiler could have been off for much of that time; its duty cycle will depend on the difference between the outside and inside temperatures and may well have been significantly less than 100%.

By rounding up you've introduced an error of 38%.

You're paying far too much ! Do the sums and you'll find it's probably worth switching and paying the exit fee.

Hi, in regards to rounding up, I’ve just added them together and got 2.98, so I re-entered that and works out at £0.69 per hour.

When the temperatures drop I’ll be doing the calculations again and for a longer period roughly 4 hours as that’s what it’s normally on for in the really cold months, perhaps longer if I find it’s much cheaper than I thought

I just had a look at some other energy companies and they seem to be around the 3.4-3.9p per kWh so not massively different. I do live in the south where everything is more expensive

Gerry1

dan~ wrote: »

I just had a look at some other energy companies and they seem to be around the 3.4-3.9p per kWh

If your consumption is 17000kWh p.a. and you reduce the unit cost from 4.1p/kWh to 3.4p (+VAT) the annual saving is £125! That's likely to be greater than the exit fee.

I'm in the South East and paying 2.72475p/kWh inc VAT.

Robin9

You can get a BG tariff "Energy and Boiler Cover Green Oct 2020v2
for under 3p

Talldave

I read the meters weekly and my Excel spreadsheet works out the weekly kWh (I just update the calorific value from the bill each month). The weekly figures show the seasonal variations clearly. The calculation to get from m3 to kWh should be on your bill.

It's pointless trying to work out an hourly cost, because it will vary massively depending on whether it's the first hour since the heating came on, or it's just ticking over having reached the target temp or whether some TRVs have shut down, etc etc.

Up to 3 months ago I spent a year in a single glazed cottage burning through 55,000 kWh of gas - every fraction of a penny counts then! I suspect you are more in the 20,000 to 30,000 range, but still no reason to stay on an overpriced tarrif.

[Deleted User]

Hi,

dan~ wrote: »

1st value 22644.769
2nd value (2hours later) 22646.212

So I have used 2 units and went onto this site

dan~ wrote: »

Hi, in regards to rounding up, I’ve just added them together and got 2.98, so I re-entered that and works out at £0.69 per hour.

It gets even better if you subtract value 1 from value 2 = 1.443, so (1.443 x 11.2 x 4.1)/2 = 33.13p.