Complaining About an Energy Supplier: The Process and the Ombudsman

When an energy supplier gets something wrong, a late bill, a faulty meter, a refund that never arrives, the fix almost always starts the same way: a complaint to the supplier itself. That is not a formality. The Energy Ombudsman, the free independent body that adjudicates unresolved energy disputes, will not accept a case until the supplier has had a proper chance to put things right, which in practice means eight weeks from the date the complaint was first raised, unless the supplier sends a deadlock letter sooner¹.

The system is deliberately simple. Complain to the supplier, keep evidence and note the date. If eight weeks pass without a resolution, or the supplier declares a deadlock, escalate to the Energy Ombudsman, which is approved by Ofgem to handle service disputes and can require the supplier to correct the problem, apologise, and pay a financial award of up to £10,000 for domestic disputes³. The service is free to consumers, most disputes are resolved within six weeks of the Ombudsman receiving evidence from both sides, and once a decision is accepted the supplier has 28 days to implement it⁵.

Complain to the supplier first: the step the Ombudsman requires

The first move in any energy dispute is to the supplier, not to the Ombudsman. The Energy Ombudsman's own guidance is unambiguous: speak to your energy supplier first to raise a complaint, and only if they cannot help will the Ombudsman step in to resolve the dispute fairly and impartially¹. Before a case can be registered, the complainant must have notified the supplier and worked with it to try to resolve the issue². The same rule applies to network operators and to heat network suppliers: contact the company, ask it to fix the situation, and give it the opportunity to do so¹⁰.

This first stage matters for two practical reasons. First, the date the complaint is raised starts the eight-week clock, and the Ombudsman will ask for that date as part of the evidence supporting the case¹². Second, many complaints are resolved at this stage without ever needing escalation, because the supplier has the account records, the billing history and the power to credit an account, change a tariff or cancel a charge directly.

Ofgem sets out what a good complaints process looks like from the household's side: the supplier must try to fix any reported problem within eight weeks and resolve the complaint, and if a mistake has been made or the customer has been treated unfairly, the supplier can be required to put things right⁸. The legal footing for the eight-week and deadlock-letter framework is the Gas and Electricity (Consumer Complaints Handling Standards) Regulations 2008, which require suppliers to follow this process¹³. The same expectation extends to smart meter issues: the supplier has eight weeks to investigate and resolve the problem, and if the issue is not resolved to the customer's satisfaction, the customer can complain to the Energy Ombudsman¹⁴.

A complaint raised with the supplier should be treated as the start of a formal process, not a passing phone call. Note the date, ask for a complaint reference, and keep everything that follows.

The eight week rule and when to request a deadlock letter

The eight-week rule is the hinge of the whole complaints system. A supplier has eight weeks to resolve a complaint, and only when that period expires without a resolution, or when the supplier sends a deadlock letter sooner, can the dispute be brought to the Energy Ombudsman¹⁵. The Ombudsman's own case registration checklist asks each complainant to confirm that it has been at least eight weeks since the issue was first raised with the supplier, or that a deadlock letter has been received¹².

A deadlock letter is the supplier's written acknowledgement that it cannot resolve the complaint: it states that the problem cannot be fixed, or that the supplier believes there is nothing more it can do⁸. Receiving one removes the need to wait. The escalation triggers, as Ofgem sets them out, are: a reported problem is not fixed within eight weeks; the customer and the energy company cannot agree how to fix it; the customer receives a deadlock letter; or the customer is not happy with the decision received⁸.

The framework is set to change. The Department for Energy Security and Net Zero has been reducing the complaint escalation timeframe from the current eight weeks to six weeks, a change the Ombudsman reported in its 2026 data release¹⁶. Until that change takes effect, the operative period remains eight weeks, and the Ombudsman's guidance continues to tell consumers to allow the supplier eight weeks to put things right unless a deadlock letter arrives sooner⁷.

For households the practical discipline is simple: raise the complaint, date it, and diarise eight weeks. If the supplier goes quiet, the clock still runs. If the supplier sends a deadlock letter, escalation can begin immediately.

About the Energy Ombudsman and its coverage

The Energy Ombudsman is an independent service, separate from Ofgem, that handles disputes between consumers and energy companies⁶. It is approved by Ofgem, the UK energy regulator, to handle service disputes in the energy sector, and it can process complaints for both domestic and small business consumers³. It is one of over 20 ombudsman schemes in the UK; other sectors, such as travel, retail, insurance, employment, financial products and banking, have their own schemes, and the Energy Ombudsman only covers energy¹⁷.

The service is free to consumers and independent of the companies it adjudicates between³. Its scale is considerable: by July 2026 it had helped resolve complaints for over one million consumers, marking twenty years of free, independent support to consumers with unresolved energy complaints¹⁸.

The Ombudsman's role is adjudication, not regulation. It does not supervise suppliers day to day, that is Ofgem's job, and it does not act as a campaigning body. It examines the evidence from both sides of a specific dispute and decides what the supplier must do to put that dispute right. Its decisions bind the energy company but not the consumer, who is free to reject the outcome and pursue the matter elsewhere¹⁹.

Complaints it handles: suppliers, brokers, networks, Green Deal and heat networks

The Ombudsman's remit covers five categories of energy company: energy suppliers, energy brokers, network operators, Green Deal providers and heat network suppliers⁷.

• Energy suppliers. The most common category, covering billing and service disputes: late, incorrect or missing bills, back billing, being overcharged, a faulty meter, poor customer service, and refusing to refund credit from an account⁸.
• Energy brokers. Disputes with third party intermediaries that arranged a contract, a growing category as more households switch through comparison sites and brokers.
• Network operators. The regional companies that own the wires and pipes. The Ombudsman can consider disputes about network operators where there is a loss of service or a problem with a connection or repair¹⁰.
• Green Deal providers. Disputes where a Green Deal provider is unable or unwilling to help when something goes wrong with a Green Deal plan²⁰.
• Heat network suppliers. From 1 April 2025 the Ombudsman can help consumers and small businesses resolve heat network disputes²⁰.

Heat network consumers gained further specific grounds of complaint under the Energy Bill Relief Scheme and Energy Bill Discount Scheme legislation. A complaint can be made if the heat network supplier has not notified the customer that it benefited from the scheme, has not explained how it will pass the benefit on, has not passed the benefit on within the timeframe the regulations require, or has otherwise failed to comply with the pass-through requirements¹¹. Official guidance for the sector confirms the sequence: consumers should first notify their heat supplier and work with it, the heat supplier has eight weeks to resolve the complaint, and the party responsible for handling complaints after that is the Energy Ombudsman²¹.

Two further categories have joined the scheme. From 8 January 2026 the Ombudsman can handle disputes for a number of flexibility service providers, the companies that operate domestic flexibility and smart-charging arrangements²⁰. And for households with solar panels claiming under the Feed-in Tariffs scheme, a domestic or micro business FIT generator whose complaint with the licensee is unresolved after eight weeks can escalate to the Energy Ombudsman²³.

Eligibility: homes, microbusinesses and small business limits

The service is open to domestic consumers, micro-businesses and small businesses⁷. For a household, eligibility is straightforward: the account is a domestic energy account. For businesses, the thresholds matter, and they differ between the micro-business and small-business categories.

A company qualifies as a micro business if it meets the consumption test or the employee and turnover test; the usage thresholds apply to the fuel that is the subject of the complaint⁷. The small business category is broader, and it is the one that carries the higher maximum award: up to £20,000 for small business disputes, against up to £10,000 for domestic disputes⁵.

The boundary has teeth. Guidance on the eight-week and deadlock-letter framework records that a case from a larger business would not be accepted unless the supplier explicitly requested the Ombudsman to take it¹³. A company that exceeds every threshold is outside the scheme altogether.

For heat networks, the eligibility mirrors the main scheme: consumers and small businesses can use the service for heat network disputes from 1 April 2025²⁰.

Raising your case: routes, proof and the next steps

Escalation begins on the Energy Ombudsman website, where searching for the name of the energy supplier starts the dispute process¹⁷. Cases can also be raised by email to enquiry@energyombudsman.org, by phone on 0330 440 1624 (option 3 for heat networks), or by post to Energy Ombudsman, P.O. Box 966, Warrington, WA4 9DF³.

Before registering, the Ombudsman asks the complainant to confirm three things: that the supplier named is the correct company to raise the dispute against and matches the name on the account holder's bill; that the complaint has already been made to that supplier; and that at least eight weeks have passed since the issue was first raised, or a deadlock letter has been received¹². The fourth requirement is evidence: sufficient material to support the case, including the date the complaint was raised with the supplier¹².

The details worth having to hand are the energy supplier's name, the name of the account holder, the account number, and the date the complaint was first raised with the supplier¹². Beyond those basics, the evidence is whatever shows what went wrong: bills, meter readings, photographs of a faulty meter, emails and letters, and a note of calls with dates and names.

Once the complaint is escalated, the process follows a set sequence. The Ombudsman will ask for information and evidence relating to the complaint, review the evidence from both the consumer and the energy company, inform the consumer of its decision, and give the energy company a set of actions to resolve the problem⁶. The consumer does not need to make a legal case; the Ombudsman weighs both sides' evidence itself.

What the Ombudsman can and cannot decide or award

The Ombudsman's remedies fall into three groups. It can tell suppliers to take practical action, such as crediting or cancelling an account, or changing a tariff; to make an apology; or to offer a financial award, and it can combine these. It may also make recommendations intended to prevent the same issue happening again⁵.

Financial awards are capped by scheme: up to £10,000 for domestic energy disputes and up to £20,000 for small business disputes, with the same caps applying to disputes with flexibility service providers for domestic consumers and micro businesses⁵. The level of the maximum award can vary depending on the type of energy company and the Terms of Reference covering that part of the scheme⁵.

The caps are ceilings, not expectations. The Ombudsman states that its average award is around £50, and that its financial awards are based on the cost of putting things right, such as ensuring the consumer has been charged accurately, clearing unfair charges or fixing faults, rather than on any notion of punishment⁷. A real case illustrates the scale: the Ombudsman's one millionth case, resolved in 2026, required a supplier to reimburse £240 of emergency call-out fees, apply a £350 goodwill credit and provide a formal written apology¹⁸.

Just as important is what the Ombudsman cannot do. It cannot punish companies, dictate how companies operate, or issue fines⁵. Its decisions bind the energy company but not the consumer, so a household that rejects an outcome can take the matter to court instead, though it then forgoes the Ombudsman's remedy¹⁹.

How long each stage takes, from referral to resolution

The Ombudsman's published process carries a clear deadline: it will inform the consumer of its decision within six weeks of escalation⁹. In practice it often moves faster than that, since most disputes are resolved within six weeks of the Ombudsman receiving evidence from both parties⁵.

The full timeline for a household, from first complaint to implemented remedy, therefore looks like this:

1. Raise the complaint with the supplier and record the date.
2. Allow eight weeks, or wait for a deadlock letter if one arrives sooner⁷.
3. Escalate to the Ombudsman with evidence.
4. The Ombudsman reviews evidence from both sides and issues a decision within six weeks of escalation⁹.
5. If the decision is accepted, the supplier has 28 days to implement the remedy⁷.

Two changes to these timescales are in motion. The escalation window is being reduced from eight weeks to six weeks, as reported by the Ombudsman in August 2026¹⁶. And the Ombudsman's twentieth-anniversary announcement recorded the same reduction, from the current eight weeks to six weeks, as part of reforms to the scheme¹⁸. Until those reforms take effect, households should work to the eight-week rule.

If the supplier fails to implement an accepted remedy within 28 days, that failure is itself a fresh grievance, and the household can return to the Ombudsman with it.

Support available before you escalate

Escalation is not the only route, and for some households it is not the best first step. Citizens Advice is the statutory consumer body for energy complaints in Great Britain, and its consumer service can advise on a dispute before any complaint is formalised; the energy consumer bodies landscape also includes Consumer Scotland and the Consumer Council for Northern Ireland for their respective nations.

For vulnerable consumers, the Extra Help Unit supports by raising complaints with energy suppliers on their behalf, particularly where there is a risk of disconnection or complex personal circumstances²⁴. The rule before escalation is the same regardless of who raises the complaint: the complaint must go to the supplier in the first instance, and only if the issue is not resolved after eight weeks, or a deadlock letter is received, can it go to the Ombudsman²⁴.

The Ombudsman itself acknowledges that access to the scheme is uneven. Its review for the Ofgem call for evidence stated that too many consumers who could use the service either cannot or choose not to, for reasons including being unaware of who the Ombudsman is or being daunted by the process²⁵. For a household unsure whether its case qualifies, a conversation with Citizens Advice before the eight weeks expire costs nothing and can clarify what evidence will be needed.

When the Ombudsman has no power to act

The exclusions fall into three groups.

Companies outside the scheme. The Ombudsman only covers its member companies: energy suppliers, brokers, network operators, Green Deal providers, heat network suppliers and, since January 2026, certain flexibility service providers²⁰. Complaints about other sectors belong to other ombudsman schemes¹⁷.

Complaints outside its remit. The Ombudsman can consider complaints about electric vehicle charging at a consumer's home, but it cannot consider complaints about charging away from the home²⁵. It cannot punish companies, dictate how they operate, or issue fines, so a household looking for a penalty rather than a remedy will not find one⁵.

Businesses above the thresholds. A case from a larger business is not accepted unless the supplier explicitly requests it¹³.

Ceased suppliers. When an energy supplier ceases trading, Ofgem appoints another supplier to take over its customers, so supply continues³. The complaint does not die with the failed company, but it changes shape: the account, and any unresolved dispute, transfers to the new supplier under the Supplier of Last Resort process. Households in this position can read about the wider pattern of supplier failures and what happened to customers' credit balances.

How the complaints process affects independence at home

A household's energy independence is not only about generation and storage; it is about the ability to hold the companies it depends on to account. Every home with a grid connection is in a relationship with a supplier it did not choose to be billed by, and the complaints system is the one lever that works without hiring a lawyer or going to court. It is free, it is binding on the company, and it has now resolved disputes for over one million consumers¹⁸.

The limits are worth stating plainly. The Ombudsman puts things right after the event; it does not prevent the event. It cannot fine a supplier that treats its customers badly, cannot dictate how companies operate, and its average award of around £50 reflects that its job is restitution, not deterrence⁷. The Ombudsman's own review for the Ofgem call for evidence conceded that too many consumers who could use the service either cannot or choose not to, whether through unawareness or because the process feels daunting²⁵. A household that knows the route, the eight-week rule, the deadlock letter, the evidence to keep, is materially less dependent on the goodwill of its supplier than one that does not.

For homes pursuing deeper independence, through solar, batteries, heat networks or smart charging, the scheme's expanding remit matters. FIT generators, heat network customers and, since January 2026, some flexibility service customers all now have the same route to redress that ordinary supply customers have had for twenty years²³. The more of your energy life that runs through a company, the more valuable a free, binding complaints process becomes.