Updated on 08/09/25 by Chris_OVO:
Hi @Anders95 I think i would start by getting a boiler engineer to look at your setup. Particularly your controls.
On first inspection it doesn't look like the issue is related to your smart meter given the usage pattern when you are away.
1. We need to see the daily usage page for the gas readings so we can see the 30min readings. Just to check when the gas boiler is firing up. For a day when you were at home, and a day when you think the boiler was off, but it still looks like you used some gas. I think your boiler may be firing up every other day when you are away. It will also help check your boiler isn't on for more than 4.5 hours normally.
2. You have your water on for quite a long time 4.5 hrs. This seems a lot for the size of your household. It obviously depends on usage e..g use of showers and baths., but still that seems high. Especially as you have a modern tank. Do you know the size of the tank? Have you tried reducing the time?
3. I would check the thermostat on the tank to see if it is set at a too higher temperature.
4. I am not convinced the boiler is actually off when you are away. On first inspection it looks like it is still on and firing up every other day for a short time as the water in the tank has cooled down a bit naturally perhaps .
5. It doesn’t look like you have a gas leak as you have a zero reading every other day when you are away. Unless it is something in the boiler when it is turned on. But you would certainly smell the gas leak then if it was happening. So i don't think it is that.
6. Unfortunately with a tank you will end up heating water you don't actually use. You have a modern tank so this will help, but some of the water will cool before you use it. That is not the larger issue you are seeing though i think.
7. There is a small chance you have a leak on one of your hot water pipes from your boiler so you are heating water you are then loosing somewhere. But that doesn't explain the usage pattern when you are away.
8. You could try downloading this app and seeing what is says for your gas readings, especially to see if the app can see your 30min readings.
https://www.glowmarkt.com/
9. You are right, there is no way you should be using 800kWh of gas just for water heating. That would be 9600 kWh a year. A typical house only uses 12000kWh for heating and water according to the ofgem figures and most of that is for heating and not hot water.
Does that help?
