Inaccurate cost calculation on EV tariff on statement


I recently switched to the EV tariff. I do have a smart meter in my flat that can take and submit readings every half an hour as required by the EV tariff. In fact, the “Day” tab of the Energy usage section in the Bulb app shows the correct daily meter reading and cost, which means that Bulb must already have received the correct electricity consumption measurements for calculations under the EV tariff. I have verified this by connecting the IHD to my Smart Things app (based on the article 360034651651-Setting-up-SmartThings-Energy-Control-STEC-) to get detailed readings at 5-minute intervals and then calculating the daily cost using the night and day rates of the EV tariff, including the daily standing charge.

I show below the daily cost as reported in the “Day” tab of the Energy usage section in the Bulb app (I can supply screenshots for these if necessary). The total sum is significantly less than what the recent statement I have received (4th Jan to 4th Feb 2022) shows (£144.82 compared to £211.06). In fact, on the statement, the night and day readings do not seem to be measured correctly at all as I cannot see any detailed breakdowns that are in agreement with the information shown on the Bulb app, which is what I have based my decision to stay with the EV tariff on.

I am wondering if this can be looked into and rectified if necessary?

Many thanks!

Daily electricity cost

04/01/22 £4.73
05/01/22 £4.41
06/01/22 £4.97
07/01/22 £5.17
08/01/22 £5.98
09/01/22 £5.39
10/01/22 £3.67
11/01/22 £4.10
12/01/22 £4.46
13/01/22 £4.75
14/01/22 £1.64
15/01/22 £0.70
16/01/22 £4.07
17/01/22 £6.38
18/01/22 £5.33
19/01/22 £4.70
20/01/22 £4.65
21/01/22 £5.66
22/01/22 £5.37
23/01/22 £6.12
24/01/22 £4.82
25/01/22 £5.98
26/01/22 £4.75
27/01/22 £4.26
28/01/22 £4.51
29/01/22 £5.67
30/01/22 £5.91
31/01/22 £4.53
01/02/22 £4.20
02/02/22 £3.73
03/02/22 £4.21

Sum £144.82

Hey @dorebase2006 thanks for your message.

Charts may not always exactly match the statement. The difference should be only pence however it should not be by such a considerable amount.

In general, the chart is the most accurate representation of your usage, but statements are the easiest way of understanding your cost.

If there have been changes in your billing date, the charts will change to match the new date and therefore won’t match billing periods on old statements.

Could you confirm if your IHD is showing similar costs or is that different too?

–Carl :bulb:

@Carl_at_Bulb Thank you for your reply! My IHD shows similar daily costs to the app (but not exactly the same because the IHD doesn’t know how to switch between the day and night rates on the EV tariff I believe – it just uses the flat Vari-fair rate in its cost calculation, which is fine, since this does not affect the measurements it sends to Bulb in any way).

I have taken another look at the statement and it shows that the night measurements are only estimates, even though half-hour readings are submitted to Bulb. The day readings on the other hand are too high: they suggest that I use on average 24.6 kWh during the day, but this is not right because every day I use around 24 kWh in total with about a third of that during the off-peak hours (2 am to 6 am). I have made sure that this is the case by monitoring the day and night meter readings, and also by putting my appliances on correct timer settings.

I am just wondering if this can be checked? It seems that all of the daily smart-meter readings are put under the day rate (which is very expensive) and none of the smart-meter readings goes under the night rate, which results in an estimate being used instead. This means that I am being charged twice for the amount of energy used during the off-peak hours: once on the day rate using the actual measurements, and once on the night rate using the estimates.

Many thanks!

I Have Ev tarrif as well.

Personally the IHD is useless.

I never shows the correct usage for electricity ( worked ok on standard tarrif)

Not even sure it is aware of night tarrIf.
They aren’t correct anyway over 50% out.

The smartthings app was OK at the beginning now shows Crap most of the time.

Meter went offline and too 4 months to get a “hub reset” after being given useless information that it could be done manually.

For now I just use the Bulb app and don’t bother with IHD.

Beware if you try and report issues with smart meter they will drive you nuts explaining how to switch on and off the smart display.

Good luck

@keithryder Thanks! I do trust the Bulb app as the daily usage data on there is quite accurate. I think the smart meter is fine since the readings shown in the Bulb app are still sensible. It’s just how those readings are used to calculate the statement that seems very unreasonable. Some people have reported this (community bulb co uk/t/product-update-our-ev-tariff-is-in-beta/101164/24) and it seems like it’s a fixable bug, so I’ll just wait and see what they have to say.

What is wrong on your statement?

I can see mine with day and night tarrIf and the amount of units used.

Is it wrong units used or wrong tariff ?

Hi @dorebase2006 :wave:

I just had a look over your account and can see that we have only been getting one rate from your meter, which is why part of your statement will have been on estimates.

I’ve reached out to our smart metering team to see why this may be, and will be in touch with you via email once I have an update.


@keithryder The day and night amounts are wrong. In fact, the night amount is only an estimate.

@Ele_at_Bulb Thank you very much Eleanor! I look forward to your email!

Hi @Ele_at_Bulb, just wondering if there has been any update on this?

Many thanks!


It’s been more than a week since this issue was logged. I am wondering if there has been any update?


Hi @dorebase2006

I’m really sorry for the delay on this one, I’m actually still waiting on a reply from our smart team.

I’ve just chased this up with them, and have just sent over an email to you to touch base.

Please let me know if you have any questions in the mean time.


@Ele_at_Bulb No worries at all, many thanks for the update Eleanor!