Would I have a good, (if any) argument?

I find the in house display a useful gadget to give you an idea of what you are using on the day. I am with Octopus and when there are changes in tariffs they tend to split the bills for that month. One for the existing price and one for the changed price so I can clearly see how much I am paying. Certainly when the prices were at their peak I started to look more closely at what was being used so that I could make a greater effort to reduce costs, although rather than a spreadsheet I used this years bill against the same one a year before.

David

If you are concerned why not just phone or email your energy company? I am with Octopus and we have no issues with either method of contact and speedy replies. 

I find it a useful guide, rather than anything else. Also useful for showing you have not turned something off. As far as costs are concerned the Eon App on my pad or phone tells me everything I want to know about costs, even if I do not want to know it.

The point is, my supplier is, in effect,  stating two different unit prices for electricity, one on the online account details and a different one on the inhouse display. 

John, just phone up and query it. Don’t leave it long if you are concerned. They will sort things out for you. 

Is your display unit connected to the internet in some way? Our is and updates the prices when they change.

But any future forecast of your yearly prices will be based on your consumption and the prices in effect at that time, or at least that's how ours are done.

But yes as said guery it. 

The display unit is connected to the internet. That is how the supplier knows what I have used and it is how they download to me the unit costs for the energy. I could contact the supplier and tell them I believe the smart meter isn't charging me enough OR I can keep quiet until the bill arrives at the end of the contract and argue with them that their smart meter display shows the electric to be at a lower price than their online tariff details. Would they, or I have a leg to stand on? If one goes into a shop to buy an item marked at £X one does not  expect to be told that it is actually more expensive.

The moral of all this is check and check again. I could have gone on until the anniversary next April believing that the total costs that the display unit is showing is correct, and then be faced with paying far more than the display indication. But I didn't I checked and saw the discrepancy so I know what I will / should be paying. At that time I will make them aware of the difference in prices and see what they have to say about it. I did complain about a billing issue some years ago and was awarded £50 credit to cover my inconvenience so perhaps worth a try again.

As I understand it Smart Meters have their own SIM cards that connect back to the supplier and the internal to house display is connected to those SIM's rather than the house WiFi. I have had the odd problem where the display has lost contact and I have had to move it nearer the meters to reconnect. 

As you appear to have a difference you could check whether the display included the daily standing charge? I don't think VAT will be included.

David

Smart meters do not connect to the 'normal' internet. A simple search revealed the following -

https://www.smartenergygb.org/faqs/how-do-smart-meters-work#:~:text=Smart%20meters%20use%20an%20entirely,is%20solely%20for%20smart%20meters.

Just speak to your supplier, John, as they’re the ones who can resolve this.

I do not think you would have a leg to stand on.   The IHD is not the Smart Meter, it is merely a device to indicate what you are using.  I presume it does correctly show the number of units you are using, just not the correct price?

Your supplier knows what you are using by collecting data from the Smart meter itself and uses those figures to prepare your bill.

Since the unit prices are clearly stated in the calculation on your bill, and every bill will show the tariff you are being charged on, you cannot claim you did not know how much you are using/spending.

Do you not pay either monthly by direct debit, or full bill amount?  If by DD then they will increase your DD if you fall much behind. These things are usually reviewed every 6 months, or even more often. Only where there is a dumb meter and you do not supply regular readings are you likely to fall behind.

The unit prices for both gas and electricity went down on 1st July, so if your IHD is still using the previous price of a fuel, it will be actually be a higher  price at present.