Last reviewed: May 2026
Key facts:- Smart prepayment meters can be topped up through the supplier app, online account, the In-Home Display (IHD) in some cases, PayPoint and Payzone outlets, or by phone.
- Top ups typically appear on the smart meter within minutes, although signal issues can occasionally delay credit by several hours.
- Smart meters do not normally need a 20 digit code; the credit is sent directly to the meter over the wide area network.
UK Energy Guides › Smart Meter Top Up Guide
Smart prepayment meters work differently from the older Keypad meters. Most smart prepayment top ups happen automatically: the customer pays, the credit is sent over the smart meter wide area network, and the credit appears at the meter without any code being entered. This guide explains the main top up routes, what to do when the credit does not show up, how emergency credit works, and how to switch between Direct Debit and prepayment on a smart meter.
How Smart Prepayment Differs from Keypad
Smart prepayment meters communicate with the supplier over a Wide Area Network (WAN). The meter regularly sends usage data to the supplier and receives commands such as credit top ups, tariff updates and connection or disconnection orders.
When a customer tops up, the supplier sends the credit to the meter as an electronic message. The meter receives the message, validates it, and adds the credit to the balance. The customer does not normally enter a 20 digit code.
Some smart meters also support manual codes as a fallback. These are useful when the WAN signal is weak or when the meter has been in dumb mode and is being brought back online. The supplier customer service team can generate a manual code on request.
Top Up Routes
Most suppliers offer top ups through their smart phone app. The customer logs in, selects the top up amount, and pays by debit or credit card. The credit is sent to the meter within a few minutes.
Online top ups through the supplier website work the same way. The customer pays online and the credit is dispatched. The customer can see their meter balance on the IHD or by walking to the meter.
PayPoint and Payzone outlets accept top ups for many smart prepayment meters. The customer takes their supplier prepayment card to the till and pays. The credit is sent to the meter electronically. Some suppliers also support phone top ups through their customer service team.
Emergency Credit and Friendly Hours
Smart prepayment meters offer emergency credit when the balance runs low, usually around 5 pounds initially with the option to extend further. The customer accepts the emergency credit through the IHD or by pressing a button on the meter.
Emergency credit is a loan and is deducted from the next top up. The household will need to top up by at least the emergency credit amount plus a small ongoing usage buffer to get back to a positive balance.
Many smart meters have friendly hours - evening and overnight periods during which the supply will not disconnect even if the emergency credit runs out. The supply restores fully when the next top up is made. Friendly hours are particularly common at weekends and in winter.
When Top Ups Do Not Appear
Most smart prepayment top ups appear within a few minutes. Where the credit does not appear, the first step is to check the meter balance through the IHD or by walking to the meter and pressing the relevant button.
If the credit is missing, the customer should contact the supplier customer service team. The supplier can confirm whether the credit was dispatched and re-send if necessary. A manual 20 digit code can be generated as a fallback.
WAN signal issues are the most common cause of delayed credit. The meter receives the credit when it next establishes a successful WAN connection. In rare cases of persistent signal problems, the meter is operated in dumb mode and a manual code is used for each top up.
Switching from Prepayment to Direct Debit
Customers on smart prepayment meters can switch to a credit billing mode (typically direct debit or pay on receipt of bill) without the meter being replaced. The supplier can change the mode remotely through the smart meter network.
The Ofgem rules require suppliers to offer a switch from prepayment to credit billing where the customer is creditworthy and able to pay regularly. This is a recent change reflecting concerns about prepayment customers paying higher unit rates than direct debit customers.
Switching back from credit to prepayment is also possible if the customer prefers. Smart meters give households much more flexibility than the old Keypad meters, where switching mode meant physically replacing the meter.
Smart Meter Modes and Settings
Prepayment vs credit mode. Smart meters can operate in either prepayment mode (customer pays in advance) or credit mode (customer is billed monthly or quarterly). The mode can be changed remotely by the supplier without replacing the meter, subject to creditworthiness in the case of credit billing.
Time-of-use tariffs. Some smart meters support time-of-use tariffs, where the unit rate varies by time of day. Off-peak periods (typically overnight) have lower unit rates than peak periods. This can save money for households able to shift consumption.
Energy display. The In-Home Display (IHD) shows the current balance, usage, and other information. Some IHDs also show carbon impact and forecasted cost. The IHD is provided free with the smart meter and is intended to help customers manage usage.
Sleep mode and auto-readings. Smart meters periodically wake to send usage data to the supplier over the WAN. The frequency is typically once a day or once a week. The supplier uses this data for accurate billing. The meter can also be polled on demand by the supplier for specific reading.
Where to Get Free Independent Help
Citizens Advice consumer service is the official source of energy advice in Great Britain. The service provides free help with smart meter top up, bill disputes, switching, prepayment meter issues and energy supplier complaints. The Citizens Advice supplier comparison ratings are also updated quarterly.
The Energy Saving Trust provides free, impartial advice on reducing energy bills through efficiency improvements. Their free home energy calculator estimates potential savings from insulation, heating upgrades and behaviour changes. The Trust also identifies available grants such as ECO4 and the Boiler Upgrade Scheme.
Ofgem is the energy regulator and sets the rules that suppliers must follow. The Ofgem consumer pages explain rights, the price cap, supplier obligations and how to make complaints. The Energy Ombudsman is the binding dispute resolution body for complaints not resolved by the supplier within 8 weeks.
Supplier hardship funds run by individual energy suppliers offer one-off grants for arrears, white goods and boiler servicing. The British Gas Energy Trust, EDF Energy Customer Support Fund, Octopus Energy Assist and similar funds are accessible regardless of which supplier the customer is currently with.
In Scotland, Home Energy Scotland is a free advice service funded by the Scottish Government. It offers home energy assessments, advice on grants such as Warmer Homes Scotland, and signposting to interest-free home energy loans. Home Energy Scotland is the Scottish equivalent of the Energy Saving Trust English service.
In Northern Ireland, NIE Networks operates the electricity distribution system and the Utility Regulator oversees pricing and consumer protection. NEA Northern Ireland provides energy advice to vulnerable households. The Department for Communities Affordable Warmth Scheme funds insulation and heating improvements for eligible homes.
Putting It All Together
The rules above set out the legal framework, the practical steps and the support routes available. Where the situation is straightforward, the gov.uk pages and the official tools should be enough to act on. Where the situation is more complex, the free advice services listed in the previous section can usually clarify the position and identify the right next step. Many issues that look intractable at first turn out to be resolvable once the right service is engaged.
Keeping written records of communications and decisions throughout is good practice. Where a decision needs to be challenged later - through an internal complaint, an ombudsman, a tribunal or a court - the quality of the contemporaneous record often decides the outcome. Dates, names, reference numbers and copies of correspondence are the building blocks of any later dispute. The gov.uk advice pages and the relevant ombudsman or tribunal websites all set out the evidence they consider when reviewing decisions, and gathering that evidence from the start is one of the most effective protections available.
Frequently Asked Questions
Do I need a code to top up a smart prepayment meter?
Not usually. The credit is sent electronically to the meter over the smart meter wide area network. A manual 20 digit code is available as a fallback when the WAN signal is weak.
Where can I top up a smart meter?
Through the supplier app, online account, PayPoint or Payzone outlet, by phone with customer service, and in some cases through the In-Home Display.
Why has my top up not arrived at the meter?
Usually a WAN signal delay. Most top ups appear within minutes; in poor signal areas they can take longer. If the credit does not appear within a few hours, contact the supplier.
What is friendly hours?
A period (usually evenings and overnight) during which a smart prepayment meter will not disconnect even when the emergency credit runs out. The supply restores when the next top up is made.
Can I switch from prepayment to direct debit?
Yes. Smart meters allow the supplier to change the meter mode remotely. Ofgem rules require suppliers to offer this switch where the customer is creditworthy.
Is the unit rate higher on prepayment?
It can be. Historically prepayment customers paid higher unit rates than direct debit customers. The Energy Price Guarantee and subsequent reforms have narrowed but not eliminated the difference. Check the supplier tariff terms.
How long do smart meters last?
Smart meters typically have a 15 to 20 year design life. The IHD batteries last around 5 years and can be replaced. Where the meter or IHD fails, the supplier arranges a replacement.
What if I have no WAN signal at my property?
The meter operates in dumb mode. Top ups can still be made but require a manual code entered at the meter. Some areas have improved WAN coverage over time as the network is upgraded.
Can I view my usage in real time?
Yes. The IHD shows current usage. Most supplier apps also provide detailed usage breakdowns by day, week and month. Some apps offer comparison with similar households and tips for reducing consumption.
Can I have a smart meter if I rent?
Yes. The tenant can request a smart meter installation. Some tenancy agreements require landlord consent for the installation. Smart meter installation does not normally require physical modifications to the property.
How We Verified This
Information is taken from the gov.uk smart meter pages, the Ofgem information for consumers, the Department for Energy Security and Net Zero smart meter rollout guidance, the Smart Meters Act 2018, and Ofgem rules on prepayment meters and customer protection.