Gas useage

[scotview]

Gas usage in the summer with the heating off will be much less than autumn/winter/spring. I go from about 5 a day in the coldest spells to about 0.1 per day over summer. (This is meter units, ie. cubic meters of gas.)

Me

Chart below shows the monthly change for our actual gas usage, heating, hob and hot water, it reduces drastically in the summer months. Up here we need the heating on significantly more than you guys in the South.

[DrFfybes]

Your figures do seem to support this, except it started in May and the heating went off in March, but I suppose that's just a lag in reading. I'm doing more regular readings (or was, pre the smart meter, now I just take them from the bill) due to the total mess Eon made of my electricity readings since 2018, for which they had to pay me £100 compensation (sorted out earlier this year) - I've been really cautious since to keep detailed logs.

I tend to take readings monthly as our gas meter still isn't talking to the supplier. Gas use changes quickly when the weather turns.

They are currently telling me that my direct debit needs to be £400 when I am £900 in credit. This is presumably because they've somehow decided my electricity predicted use (as noted on the bill) has doubled. [...]. I am not affected by the Oct price rise as I'm on a fix til March.

They are taking the P-roverbial.We were on a fix to July this year, but last Oct they decided we were going to use loads more than I'd predicted, and tried to hike the payments - they claimed to be using 5 years of address data and weather predictions, which meant they were using the previous occupants' figures. I pointed out I'd used actuals from the last 2 years and they relented.

FWIW our daily average (on a 30+ year old boiler) last year was 6 cubic metres/day in Oct (so 66kWh/day), up to 7 in Nov, 8 in Dec, and then 11-12/day until March when it hit 14, before reducing to 8 in April and plummeting to 2.5 units/day until mid May, when it dropped to about 0.7, (coinciding with the new boiler, which doesn't have a pilot light like the old one), so pretty much a 20-fold difference between the coldest Month and the hottest.

Paul

[funduffer]

I have kept monthly records of gas usage (kWh) since I had a smart meter fitted in 2019.

I have noticed that my monthly gas usage (in kWh) has been 30% lower in the last 12 months compared to the previous year (Sep 21 to Aug 22 versus Sep 20 to Aug 21).

It is difficult to explain this, as the heating system (condensing combi boiler + radiators) has not changed and our lifestyle (retired, mainly at home) has not really changed. The automated heating schedule has also not changed, although it is manually over-ridden now and again.

I put this dramatic reduction in gas usage down to 2 things:

1. I turned down the heating output temperature from 70C to 55C last winter, to ensure the condensing boiler efficiency is maximised. This was recommended by my energy supplier, Octopus. In theory this should make the house slower to heat up from cold, but I can't say I have noticed this. It is difficult to believe this has had such a dramatic effect, so it may be due to...

2. It has been a warmer year, so the heating has been on much less!

I don't know if this helps you, melonfool, but it might provide some explanation.

FD

[UncleEbenezer]

I put this dramatic reduction in gas usage down to 2 things:
FD

Could a third thing there be Lockdown? If you customarily spend time away (e.g. hols) but missed that during 2020-1, your use could have been elevated that year.

[scotview]

I have kept monthly records of gas usage (kWh) since I had a smart meter fitted in 2019.

I have noticed that my monthly gas usage (in kWh) has been 30% lower in the last 12 months compared to the previous year (Sep 21 to Aug 22 versus Sep 20 to Aug 21).

1. I turned down the heating output temperature from 70C to 55C last winter, to ensure the condensing boiler efficiency is maximised. This was recommended by my energy supplier, Octopus. In theory this should make the house slower to heat up from cold, but I can't say I have noticed this. It is difficult to believe this has had such a dramatic effect, so it may be due to...
FD

That's very interesting. I might try that.

Does your boiler show the outlet temperature or did you measure it.

Thanks FD

[DrFfybes]

I put this dramatic reduction in gas usage down to 2 things:

1. I turned down the heating output temperature from 70C to 55C last winter, to ensure the condensing boiler efficiency is maximised. This was recommended by my energy supplier, Octopus. In theory this should make the house slower to heat up from cold, but I can't say I have noticed this. It is difficult to believe this has had such a dramatic effect,

We got a condensing boiler this summer. As you say, the reports I've seen suggest that we see marginal gains in the UK as the flow (and hence return) temp is set too high, and the boiler is only about 75% efficient at that temp.

It is running at 68C as it heats the water cyl as well (set to 60 so we can run a hot bath) as the cyl will take a long time to reach the supply temp.

I'm currently running the heating for an hour in the morning when MrsF is working and it is cold, and seeing gas use for that hour. I'll then repeat for a few days at a 55C flow temp to see if entering condensing mode really does save gas as claimed. The downside of this is it either needs to run a lot longer to heat the water, or I use the immersion heater on a timer (£20 from Screwfix) for the water. Our system is microbore, so our 28kW (IIRC) boiler can heat the water much faster than the rads can cool it when we only have a few switched on, using approx 12kW/hour so far.

MrsF is wondering why I'm bothering, but seems happy that at least I'm keeping busy

Paul

[Mike4]

I have kept monthly records of gas usage (kWh) since I had a smart meter fitted in 2019.

I have noticed that my monthly gas usage (in kWh) has been 30% lower in the last 12 months compared to the previous year (Sep 21 to Aug 22 versus Sep 20 to Aug 21).

1. I turned down the heating output temperature from 70C to 55C last winter, to ensure the condensing boiler efficiency is maximised. This was recommended by my energy supplier, Octopus. In theory this should make the house slower to heat up from cold, but I can't say I have noticed this. It is difficult to believe this has had such a dramatic effect, so it may be due to...
FD

That's very interesting. I might try that.

Does your boiler show the outlet temperature or did you measure it.

Thanks FD

I'd just like to point out this is a good idea on a condensing combi boiler as they have separate temperature controls for hot tap water and radiator water.

On a 'regular' boiler heating rads and a hot water cylinder, you'll also need to turn down the temperature setting on the cylinder thermostat or the cylinder stat may never be satisfied, leading to it constantly calling for heat but never getting up to the selected setting. This causes the boiler to cycle on and off and the pump to run continuously, perhaps wasting more energy than you are saving.

And on an older, non-condensing boiler, the savings from turning the rad temp down will be smaller as you will never force it to condense the water vapour from the flue gas, meaning you won't be recovering the 11% latent heat of condensation lost by keeping the water in the flue gas as vapour.

[MrFoolish]

Perhaps you had the hot water pre-heat turned on, and at some point it got turned off?

[melonfool]

I have kept monthly records of gas usage (kWh) since I had a smart meter fitted in 2019.

I have noticed that my monthly gas usage (in kWh) has been 30% lower in the last 12 months compared to the previous year (Sep 21 to Aug 22 versus Sep 20 to Aug 21).

It is difficult to explain this, as the heating system (condensing combi boiler + radiators) has not changed and our lifestyle (retired, mainly at home) has not really changed. The automated heating schedule has also not changed, although it is manually over-ridden now and again.

I put this dramatic reduction in gas usage down to 2 things:

1. I turned down the heating output temperature from 70C to 55C last winter, to ensure the condensing boiler efficiency is maximised. This was recommended by my energy supplier, Octopus. In theory this should make the house slower to heat up from cold, but I can't say I have noticed this. It is difficult to believe this has had such a dramatic effect, so it may be due to...

2. It has been a warmer year, so the heating has been on much less!

I don't know if this helps you, melonfool, but it might provide some explanation.

FD

I did change the flow/output but that was over a year ago. But, I agree, it has been warmer and despite home working last winter I didn't put the heating on during the day at all. It's positively baking today as well!

Mel

[melonfool]

I put this dramatic reduction in gas usage down to 2 things:
FD

Could a third thing there be Lockdown? If you customarily spend time away (e.g. hols) but missed that during 2020-1, your use could have been elevated that year.

The opposite - due to my father dying in April 2020 I was away about 4 months that year helping my mother and in 2021 the same for several weeks. And I had two holidays in 2021. Oh and for Nov 2021 I was away the whole month house-sitting for my sister!

Mel

[melonfool]

I have kept monthly records of gas usage (kWh) since I had a smart meter fitted in 2019.

I have noticed that my monthly gas usage (in kWh) has been 30% lower in the last 12 months compared to the previous year (Sep 21 to Aug 22 versus Sep 20 to Aug 21).

1. I turned down the heating output temperature from 70C to 55C last winter, to ensure the condensing boiler efficiency is maximised. This was recommended by my energy supplier, Octopus. In theory this should make the house slower to heat up from cold, but I can't say I have noticed this. It is difficult to believe this has had such a dramatic effect, so it may be due to...
FD

That's very interesting. I might try that.

Does your boiler show the outlet temperature or did you measure it.

Thanks FD

Mine has a dial on the front, you just set it.

Many are set to c80 and should be between 55 and 60. Not under 55 I don't think.

About halfway down this page:

https://www.moneysavingexpert.com/utili ... ving-tips/

Mel

[melonfool]

Perhaps you had the hot water pre-heat turned on, and at some point it got turned off?

What is a 'hot water pre heat' - I've never heard of that?

I have a combi boiler, it takes about thirty seconds for the hot water to come through.

Mel

[staffordian]

Perhaps you had the hot water pre-heat turned on, and at some point it got turned off?

What is a 'hot water pre heat' - I've never heard of that?

I have a combi boiler, it takes about thirty seconds for the hot water to come through.

Mel

Our Worcester Bosch has a preheat facility, it is supposed to speed the supply of hot water by keeping a small container of water within the boiler preheated, I believe. There is an eco mode which disables this, and I have always used this eco mode. As you say, the water still comes through pretty quickly.

[MrFoolish]

Our Worcester Bosch has a preheat facility, it is supposed to speed the supply of hot water by keeping a small container of water within the boiler preheated, I believe. There is an eco mode which disables this, and I have always used this eco mode. As you say, the water still comes through pretty quickly.

Yep, my boiler used to have the pre-heat turned on. It would fire up every 20 mins or so for perhaps a minute. Don't know how much gas this used. I eventually turned it off (had to RTFM and go through some tedious button clicking routine).

[modellingman]

Gas usage in the summer with the heating off will be much less than autumn/winter/spring. I go from about 5 a day in the coldest spells to about 0.1 per day over summer. (This is meter units, ie. cubic meters of gas.)

The earlier years in your table don't isolate summer months, they cover larger ranges which will no doubt include periods when the heating is on.

The later rows showing the "problem" are for shorter periods of a month or two from May this year, when presumably the heating was mostly off. This to me indicates nothing was wrong with the old meter.

Was the heating on much in September? If so, the new meter may be faulty. If not, however, there may be no issue.

Scott.

I did wonder about this point but thought the averages would cover it.

The heating hasn't been on at all since March, I can't figure out the new thermostat I got in Feb so I'm resisting putting it on.

Your figures do seem to support this, except it started in May and the heating went off in March, but I suppose that's just a lag in reading. I'm doing more regular readings (or was, pre the smart meter, now I just take them from the bill) due to the total mess Eon made of my electricity readings since 2018, for which they had to pay me £100 compensation (sorted out earlier this year) - I've been really cautious since to keep detailed logs.

Me

Gas usage is very weather sensitive. So usage in Winter is much higher than in Summer. Behaviours such as switching the gas central heating off at the beginning of May and not putting it on again until late September are part of the reason for this. Thermostatic control systems (and your boiler has one to avoid it overheating the water in your heating pipes even if you don't use a room thermostat) is another important factor. Plus, ever noticed how much colder cold water is in Winter than in Summer (particularly if you are supplied by reservoirs and river abstraction rather than groundwater)? More energy needed to convert it into hot water and more gas consumption if burning gas is supplying that energy. Again, another factor causing Summer/Winter differences.

The early lines of your data cover very long periods: up until March 2022 your periods varied in length between 4 months and 9 quarters. These data are great for long run average values but not so good for getting insight into the much shorter periods post March 2022.

scotview's chart provides a very useful insight into seasonal patterns of consumption which looks fairly typical for domestic consumers. His peak monthly consumption is around 8 times the minimum. I would expect a similar pattern for other domestic customers.

You have ruled out a change in volume units (from cubic feet to cubic metres) as the explanation and that seems right since failing to correct for that would reduce the readings by a factor of 30 rather than 10. You can also rule out variations in calorific value. Whilst this does vary it is typically in a range of plus or minus 5% its average.

Although your recent summer values appear, perhaps, a little on the low side they do not appear to me to be exceptionally so. Your observations may well be accounted for by keeping your central heating switched off, allied to weather effects over the past 4 or 5 months.

Your consumption rate for the beginning of October is twice what it was at the end of July. Your Autumn up-tick is to be expected and might be a little lower because of weather effects and delays in switching on central heating. In your shoes I would carry on monitoring, those as you have a smart meter I would be looking at my supplier's website to see if I could get daily readings/consumptions directly from their system. I expect you will see a sustained increase in your daily consumption rate as Autumn kicks in and Winter approaches.

modellingman
(who spent some of the early part of his career modelling the relationship at UK regional level between daily gas consumption in different market sectors and daily weather).

[UncleEbenezer]

(who spent some of the early part of his career modelling the relationship at UK regional level between daily gas consumption in different market sectors and daily weather).

Interesting. Were you pursuing science as such, or incidentally?

Did you ever look at questions like placebo? People who wouldn't dream of turning the heating on for a cool July day but who do turn it on for the same (or even higher) outside temperatures in this season?

[Mike4]

(who spent some of the early part of his career modelling the relationship at UK regional level between daily gas consumption in different market sectors and daily weather).

Interesting. Were you pursuing science as such, or incidentally?

Did you ever look at questions like placebo? People who wouldn't dream of turning the heating on for a cool July day but who do turn it on for the same (or even higher) outside temperatures in this season?

Or worse, the people who turn the heating OFF on principle on 1st April and it stays OFF until end of October no matter how cold it might be, like my employers in 1975. And my skool.

[UncleEbenezer]

Or worse, the people who turn the heating OFF on principle on 1st April and it stays OFF until end of October no matter how cold it might be, like my employers in 1975. And my skool.

You had heating in your skool? Back in the 1970s or earlier??????

Strewth, how the other half lived!

[Mike4]

Or worse, the people who turn the heating OFF on principle on 1st April and it stays OFF until end of October no matter how cold it might be, like my employers in 1975. And my skool.

You had heating in your skool? Back in the 1970s or earlier??????

Strewth, how the other half lived!

State skool, yersee...

[melonfool]

Our Worcester Bosch has a preheat facility, it is supposed to speed the supply of hot water by keeping a small container of water within the boiler preheated, I believe. There is an eco mode which disables this, and I have always used this eco mode. As you say, the water still comes through pretty quickly.

Yep, my boiler used to have the pre-heat turned on. It would fire up every 20 mins or so for perhaps a minute. Don't know how much gas this used. I eventually turned it off (had to RTFM and go through some tedious button clicking routine).

This is interesting. I'm not aware that my boiler has this but will look at the manual. It's quite small so I can't see where a tank would be. BUT - it does fire up randomly day and night (and drives me mad when I've got insomnia) and when I asked the plumber about it he said it was legionella prevention. I wasn't 100% convinced because boilers in other houses have never done that. My mum's doesn't.

But even if it does have it, there's no way it can have recently been turned off, given I didn't know it existed!

Mel