Please help - understanding my heating / hot water system

matelodave

OK the tank stat is the device with dial and looks to be set at around 55 degrees which is about right to avoid the water getting too hot and fine for legionella protection especially as you have an unvented tank and good tyrn over of water.

Try using a bit less hot water by rinsing stuff (including your hands) under the cold tap. Remember every time you run off cold until the water runs hot, you not only waste several litres of water down the sink but you also leave the same amount of valuable hot water sitting in the pipework to get cold. Try taking shorter showers or shallower baths and dont let water (either hot or cold) run down the sink whilst washing or cleaning your teeth.

We've got an Eco shower head that gives around 6litres per minute, that's around 12 litres for a 2 minute shower. A deluge shower can dump up to 15litres a minute and a ten minute shower can then use 150 litres (more than a bath full) so its pretty easy to waste it

Fishandchips80

Yes, @QrizB I think this is the tank thermostat. It’s set half way between 45 and 65, so I guess as it should be

Fishandchips80

I’ve started taking daily gas meter readings now so I ca try and get a sense of my usage

matelodave

Thats the only way to see what you are using but be careful on very cold days, dont panic if it increases dramatically.

Have you got a smart meter and the IHD (thats the thingi in the house that shows you what you are using). I dont know what gas data you can get as I've only got electricity but using the "Bright" app I can see half-hourly consumption data going back over two years.

It does allow you to build up a picture of what you are using and you can see what effect tweaking thermostats and times can have on your consumption. 

Bear in mind that at this time of the year cold days can increase your energy consumption quite considerably compared with mild ones so take it into account when tracking consumption.

Fishandchips80

Thanks @matelodave - that’s good advice. I just wish I’d paid closer attention when I moved in. It is a smart meter, but it’s broken as the supplier isn’t getting any reads, I’m having to submit them manually, so I’ve contacted them to come out to repair it. I don’t have a box in the house that shows me consumption etc. so I’ll start with the daily meter reads, and note your advice regarding when it’s cold weather. 

Albermarle

Fishandchips80 said:

I’ve started taking daily gas meter readings now so I ca try and get a sense of my usage

If there is a high usage, then it is unlikely to be related to the hot water being on all day ( which was a concern in your OP).
Those types of hot water cylinders are well insulated, and once the water reached the temperature on the thermostat , the boiler would stop supplying hot water to it.
The tank would only cool down very slowly if you do not use any hot water, so maybe the boiler might only kick back in for 10/15 minutes a couple of times a day, to just get it back to temperature again. So unlikely to the be the source of your big bills.
Most likely connected to the estimated readings.

Fishandchips80

Thanks for this advice, it’s useful to know that it wouldn’t be the hot water causing the high bill. I’ve taken meter readings 24 hours apart and it’s giving me 7 units, which I calculate as amounting to almost 80 kWh. So I think there is a high usage issue, but I’m concerned by this as it was after I’d reduced the schedule down for the heating to only come on for 1 hour in the morning and 1 hour in the evening- that’s only getting the temperature to 16-17 degrees max, and leaving it around 14-15 during the rest of the time 😫

QrizB

Fishandchips80 said:

I’ve taken meter readings 24 hours apart and it’s giving me 7 units, which I calculate as amounting to almost 80 kWh. So I think there is a high usage issue ...

How big is your house?

We've got a 1950s 3-bed semi in the central south of England and we're using less than half that much gas.

Admittedly we're currently a household of two, but hot water is less than 10kWh a day; heating is the balance, less than 30kWh a day at present.

We only get anywhere near 80kWh a day if it's below freezing.

matelodave

Still keen on finding out the boiler temperature. 

Fishandchips80

@matelodave when you say boiler temperature, do you mean what it says on the Worcester boiler downstairs? 

@QrizB it is a Victorian 4 bed detached, so is big enough, and I have three little ones here. So usage has always been relatively high. I knew that moving into an old house we’d see a rise in our bills, but I wasn’t expecting quite that much (and certainly not when we’re not able to get the house higher than 16-17 degrees)

I’ve plugged my dehumidifier in in the bedroom tonight and that’s got us an extra 2 degrees higher in the room temperature which is nice, but the other bedrooms aren’t seeing the benefit of that