How to Take Meter Readings Across a Building

Reading your own meter once a quarter is a two-minute job. Walking thirty of them across a building is a different task with different failure modes, and almost none of them are about recognising digits.

The errors that cost money on a round are clerical. A reading attributed to the wrong flat. A meter photographed twice and another missed entirely. A figure transcribed into the wrong row three hours later, at a desk, from a set of photographs that all look alike. The optical part — turning a picture of a display into a number — is the part that gets software thrown at it, and it is not where the round goes wrong.

Before you walk the round

If the meters report remotely and all you need is the supplier’s billing figure, check the portal before you check the cupboard. A smart meter that sends readings over the network makes a manual round redundant for that purpose, and the reading you take by hand will be superseded by the one the meter sent. The round still earns its place when you are apportioning between sub-tenants, reconciling a service charge, or dealing with meters that have dropped off the network — but be clear which of those you are doing.

For the reading itself, a phone camera is most of the answer. Live Text on iPhone pulls printed digits out of any photo, free, with no install — it needs iOS 15 or later on an A12 Bionic device, so an iPhone XR, XS or newer. Google Lens does the same on Android.

What they do not do is keep the readings together, in order, attached to the right meter. That is the actual job, and it is why people go looking for an app in the first place.

How to take meter readings from a smart meter

This is the part that surprises people on a first round, and it is worth knowing before you are in a riser cupboard with thirty meters to get through.

First, the meter on the wall is the meter of record. The in-home display is a separate portable device that reports what the meter has sent; Citizens Advice and Smart Energy GB both say to read the meter itself, not the display.

Second, the reading is usually not on screen. You have to summon it, and the sequence depends on the model. On a keypad meter, press 9 until IMP KWH appears. On a meter with A and B buttons, press A repeatedly until TOTAL ACT IMPORT shows with a kWh figure beneath it. On some models with a green A and a white B, pressing B first offers a “meter boost” you have to decline before it will show you anything. Then write the digits left to right, ignoring leading zeros and anything after the decimal point.

A two-rate or Economy 7 meter holds two registers and needs two readings — typically IMP R01 and IMP R02. If you cannot tell which is the day rate and which is the night rate, read both in the morning and again later the same day, and see which one moved.

The operational consequence for a building is the useful bit: your bottleneck is not recognition, it is knowing which button sequence each model wants. Photograph the model plate the first time you meet a meter. The sequence is a property of the model, so next quarter it is the same sequence, and the round gets substantially faster the second time.

The photograph is the record, not the number

A reading you typed is an assertion. A photograph of the meter face, with a timestamp in its metadata, is evidence.

In Great Britain, Ofgem banned suppliers from back-billing domestic customers for energy used more than twelve months earlier — announced in March 2018, in force for domestic customers from that May and for microbusinesses from November. That rule gives a dated photograph real value: it establishes when a meter stood at a given figure, and therefore which side of the twelve-month line a claim falls on.

So take the picture whether or not anything reads it automatically, and frame the whole faceplate rather than just the digit window. The serial number is in that frame, and a cropped shot of six digits proves nothing about which meter they came from.

What to record beside the number

Field	Why it earns its place
Meter serial number	Identifies the physical meter rather than the address. Survives tenant turnover and meter replacement, which flat numbers do not
MPAN or MPRN	In Great Britain, the 21-digit electricity supply number or the 6-to-10-digit gas one. The MPRN is usually printed on the gas meter; the MPAN normally only appears on a bill
Location, as you will describe it later	“Flat 4B, hall cupboard, left of three” beats “meter 12” when you are reconciling at a desk
The reading, whole units only	Red digits, and anything after a decimal point, are tenths and are not part of a standard reading
Register, on a two-rate meter	R01 and R02 are different tariffs. A reading with no register against it is unusable
Date, and last period’s reading	The back-billing window, and the only sanity check available while you are still in front of the meter

That last row does more work than the rest combined. A reading lower than last period’s means a misread, a meter that has rolled past its maximum, or a meter that has been swapped. A jump of roughly ten times means the red digits went in. Both are catchable on the spot and expensive to catch three weeks later.

Which digits count on a mechanical meter

On most older electricity and gas meters, digits shown in red, set behind a red border, or placed after a decimal point are tenths, and the supplier does not want them. Read the black digits left to right and stop at the red one. Water meters follow the same logic with larger stakes: black digits are cubic metres, red are litres, and there are a thousand litres to the cubic metre.

Both walkthroughs are worth reading once before a first round. Reading an electricity meter from a photo covers dial meters, Economy 7 double registers and the serial numbers that get mistaken for readings; reading a water meter covers fogged glass and odometer digits caught mid-roll.

Dial meters need a human. Four or five small clock faces, alternating direction, each read to the lower number when the pointer sits between two digits. No automatic reader is reliable on those.

Where recognition helps, and where it stops

Seven-segment displays are the hard case, and they are also most of a modern building. They are not a typeface: each digit is separate bars with gaps between them, which many pipelines split apart rather than assemble. Add the contrast falling away when an LCD is photographed off-axis and you have the commonest reason a reading comes back wrong. Why OCR gets numbers wrong explains the mechanism; the upshot is short. Get square to the display, wake it first, and read the result back against the photograph.

For a single reading, reading a utility meter from a photo in the browser is faster than installing anything, and it explains the red-digit rule inline while it works.

For a round, the feature that matters is not better recognition — it is memory. SwipeScan keeps every recognition on the device with a timestamp, newest first, so a walk down a corridor produces a list you reconcile afterwards instead of thirty separate copy-paste operations. Two limits decide whether that fits your workflow, and both are worth stating plainly: there is no batch mode, so meters go through one at a time, and there is no file export. Output is the clipboard, the system share sheet and that local history. If what you need at the end of the round is a CSV, you will be assembling it yourself, and a spreadsheet on the phone may be the better container from the start.

Submitting the readings

File each reading against the identifier the supplier uses, not the one you use. Most portals key on the MPAN, MPRN or account number, and a reading filed against “Flat 4B” is filed against nothing.

Submit while the photographs are still to hand, and keep them until the bill that used them is settled. If a figure is rejected as implausible, the portal is usually right — go back to the photo before overriding it. The meter reading tool puts each result in an editable field for the same reason: the last check is yours.

The short version

• The errors on a multi-meter round are clerical — wrong flat, missed meter, mistyped row — not optical.
• A smart meter does not show its reading until you ask. Press 9 for IMP KWH, or A until TOTAL ACT IMPORT, and record the model so next quarter is quicker.
• Photograph the whole faceplate. The dated photo is the evidence; the number is only an assertion.
• Record the serial and last period’s reading alongside the figure. A reading lower than last time, or ten times higher, is catchable on the spot.
• Recognition helps least on seven-segment displays and not at all on dial meters, which still need a person.