Why does my smart meter show I am using gas throughout the night?

[Wigeon]

Recently moved house and got a smart meter for the first time. It’s showing that almost every night we are using a few kWh every hour of the night, and weirdly 9kWh at 1.30am on this date. It’s a 20 year old boiler, set to come on in the morning and evening for central heating and hot water. There’s a hot water tank in the loft.

Any clue why there appears to be gas use in the night?

@Wigeon i had the same problem. I had gone abroad for 3 months and nobody was at home to use any hot water or heating. I was expecting my 6 month bill at that time to be around £400 because i only used 2 months of heating and hot water before i left for the remaining 4 months and had also cleared any outstanding debt beforehand. When i came back and received my bill, it was almost £700.
I was gobsmacked and thought there was a problem with my boiler etc. Or even more bizarre worries like an unsuspected gas leak or something (crazy i know).
Since i rent the house i love in i asked my landlord if i could bring the gas safety check forward, which he did.
When the gas safety guy came around and checked, he said everything was fine and asked why i wanted an earlier check and i told him it was because my bill was high and i wasnt even home for half the time.
He then checked the boiler and found it was set on pre heat.
I didnt know my boiler being on PRE HEAT would have made such a huge difference but the guy said it did because technically, even if the heating is off, it is still regularly pregeating so that the home warms up faster. So in a way, even when i wasnt home, my boiler was still heating things up.
After turning the preheat setting off, the man then also set the boiler onto economy mode.
Check if your boiler has the pre heat setting and see if it is turned off. Also check if it has the eco option.

@Propertysourcingguy - the screenshot is just showing midnight to 3.30am, and it is definitely just gas usage, as the Ovo app only shows you each fuel separately hour by hour. On the date of the screenshot (30 Dec) totally gas kWH for the whole 24 hour period was 96.77 kWh.

@R34nismo good thought, but below the usage / cost graphs on the app it specifically says:

”Why don’t these costs match my bills? It’s because we haven’t included regular costs like standing charges or plan upgrades, or things like VAT”

Pilot light might be the culprit though.

@Topseyt123 - it’s got an actual flame I can see - as it’s a 20 year old boiler (ish), I’m guessing that’s the old fashioned pilot light system?

@AToughCookie - ah interesting. What a pain you ended up paying £700! Was that a combi boiler? I don’t know if the hot / cold water tank sort have a pre-heat function? Will have to investigate.

At least this thread has spurred DH and me to get up in the loft and properly look at the tanks (we’ve only been in the house 5 weeks, which has included both of us working, being ill twice, hosting Xmas, so we hadn’t actually made it up into the loft…), to discover the hot tank only had the foam insulation but no cylinder jacket, so DH bought and fitted one of those today, and we also used the various unused bits of pipe insulation left in the loft to insulate some of th pipes which only had some ancient looking thin insulation round them. So hopefully that will help a bit too.

There is often a delay with smart meters showing gas usage. Could this actually be showing your use from a few hours previously?

Also found the remains of the Daily Mirror from 1950 up there, and some of the immediate previous owners’ son’s writing / drawing from when he was very very small (he’s now in his 20s), so have been able to rescue that for them!

@Wigeon with a tank it will stay hot for some time if well insulated - ours did. Does your boiler have on (constant), on (timed) and off for water and the same for heating? So you could have heating on all the time or just at set times or completely off and the same for water? Wondering if you havw somehow got the water on all the time rather than timed, in which case. Or if it is designed to come on when the tank temperature falls below a specific setting? Maybe look online for the user guide and failing that ring the the manufacturer.

It's very likely with the cold weather the tempreture is dropping below 10 degrees during the night. Our anti frost setting on combi boiler is 5 degrees but it has turned on twice during the night. But each time our fridge thermometer which reads the room tempreture too has shown the tempreture at 2-3 degrees when the heating is off. The 5 or 10 degrees minimum is to avoid pipes freezing so it's likely to have come on then.

My smart meter shows three pound in the morning for my one storage heater used on night rate,is the amount shown cheap rate charge,it works out about 40p per hour

A cooker gas burner is normally in the kW range, so 1 kWh is far more than a pilot light, which I guess would be 0.1 kW per hour or less.

My guess the large value would be frost protection. But the other would be always on water heating.

If the water heating is always on you will find that every now and then the hot water tank temperature may drop below the trip point and this will make the boiler fire up to heat the water above the trip point. So you will get a constant run of turning on and off at relatively low level.

The 9 kWh sounds more like frost protection.

I guess the question is can you actually see the boiler firing up and is the actual meter registering an increase as opposed to the smart meter ?

It's possible that the low constant on could be a leak, so I would want to find out what is causing that.

There might be a valve that switches the hot water on and off for the heating system, mine has it. It is like a tap, operated by a solenoid. Sometimes, with use, it becomes sticky or fully stuck, so the heating is on at random times or will not stop even after reaching set temp. Are the radiators coming on at 1:30?
If you do not find other explanation, like the standing charge added, then give a heating engineer a call.

Silly thought have you checked the timer doesn't come on during the night as they typically have 3 possible on, off timings through the day.

Just a thought.

The spike could very well be your water tank being heated up. What time have you got the boiler set to to heat up your water? Is it around the same time as the spike?

Standing charges would not cause your Kwh to spike.

If there was a leak there would be a consistent spike.

Check your timings and keep a close eye on your daily usages over 30 days. If there is a consistency you need not worry.

If there is an inconsistent spike it would suggest that something is using energy at that given time.

If you notice that the spikes are increasing in duration contact your supplier and ask them for their "energy saving tips"

Decide whether you should upgrade your boiler to a newer more economic boiler.

Definitely sounds as if you have a frost stat on your boiler. It will by pass everything if the temp drops below a certain level, even if your heating is switched off.

It is definitely not from a pilot light as 1. the pilot light uses only a very small ammount of gas to keep it alight and 2. otherwise it would be using this amount almost the time.

either your boiler it starting firing up in at this time to meet a temperature or heat water for storage.

check all your timers and see if any are set.
look at your smart usage and see if it this time everyday.

It could be a frost stat or pipe stat that is calling for it to start up usually once it drops to about 5 degrees on the pipe.

if you have a pipe stat it will usually be attached to a pipe near the boiler or thermostat and will look similar to the pic I've added.

I also recommend the hugo app to link to your smart meter too.

Have you got a camera or smartphone you could set up in front of the boiler to record overnight? Some can go for hours on a low picture resolution, especially if plugged into a powerbank or mains adapter. Or maybe a security cam or baby cam? That should show it coming on, although a 20 year old boiler may not have a detailed display.

My bet is frost protection mode kicking in or system being unwittingly programmed to maintain min temperature.

Have the diverted valves checked and the thermostat on the boiler. My tank thermostate fluctuated giving demand when I didn't want it. This was faulty. Once replaced make sure its set above 60c to protect from legionaries disease. Additionally check all gas pipe joints even at the exit valve of the meter with soapy water and look for any bubbles.

Either extra insulation won't do any harm from an economical and pipe protection point of view.

Don't know how many do it, but we actually had our engineer service and check the system over when we moved in - he picked up one minor thing and gave us advice on it. Also, we knew the thermostat wasn't right and he replaced.

Does you smart meter showing an increased use most nights? If so, looks like something is firing up. Just annoying trying to figure out why.

Thanks v much for all the further comments. I’m sure the heating and hot water are only set for limited periods during the day time /evening, and definitely off at night. We have been fiddling about with the control panel settings regularly as we’ve only recently moved into the house.

A frost stat sounds like the most likely culprit, although inside the house definitely isn’t ever 5 degrees and I would guess not even 10 degrees even with the heating off at night (apart from when it was snowy recently and our bedroom got down to 12 degrees, so the hallway with the thermostat was probably colder). I guess it’s possible the loft, where the hot water cylinder / cold tank are gets to 10 degrees? But then surely the boiler isn’t connected to the temp of the loft - unless it’s about protecting the pipes in the loft? Sounds like we should look for a pipe stat up there?

We’ve also booked the chap who used to service our old boiler to come round on Monday and give us some good advice on what’s going on, whether we should bite the bullet and replace the boiler, or even the whole system. The house surveyor who did our report before we bought the house recommended getting rid of the cold water tank and changing the cylinder to the sort which doesn’t need the tank (presumably all of this is £££).

Maybe get a new combi boiler and join British Gas pay monthly. X

I actually work for a well known utilities company. It wasn't just guess work it was genuine advice.

I would love to hear more about this as my combi boiler does that, how did you turn the preheat off?

I need to read this after coffee!!

GetThatHelmetOn ours has an eco button on the front, which is switched off if there's a power cut - very easy for us, we just press - boiler is in kitchen though so very easy to hear if it keeps kicking in unexpectedly. If you haven't got a manual, search online for your make and model.