Russell Andrews
Dealing with a poor heat pump installation is stressful, especially when the first question is who you are meant to complain to. This guide draws on an episode of the Renewable Heating Hub's Homeowners' Q&A podcast, published in November 2024, in which Cathryn Wolfenden of HIES and Hassan Abdalla of REST UK talked through what homeowners should do when an installation falls short. Watch the full episode on YouTube.
Video: the Renewable Heating Hub Homeowners' Q&A podcast, recorded with HIES and REST UK.
Start with your installer, and put it in writing
Both guests agreed on the first step: go back to the installer who fitted the system. Anyone who belongs to a consumer code must have a proper complaints process, and that process is part of their accreditation. Phone calls are fine to get things moving, but Cathryn's advice was to follow up formally. A recorded letter is still the clearest evidence, because a single complaints inbox can go unattended if one person is off. Email as well if you like, but keep copies of everything.
The process is not meant to be a trap. If you have no heating or hot water and cannot reach your installer, HIES says it can move straight to a formal complaint rather than insisting you have sent a letter first.
Find out which consumer code your installer belongs to
If the installer cannot or will not put things right, check your paperwork for the consumer code named in your contract. For a member of HIES, you contact HIES customer service, which will look at the complaint, give guidance and, where needed, arrange an inspection. The key point from the episode is timing: a contract signed while the installer was a member is covered, even if they have since left or stopped installing that product.
Certification bodies and consumer codes do different jobs
Certification bodies such as MCS, NAPIT and NICEIC set and check technical standards for installers. In the speakers' experience, they are not set up to visit homes or mediate disputes, which is why homeowners can end up passed between organisations. A consumer code is the route for a complaint about how you were treated and whether the work meets the standard. For a technical fault, a certification body can still be useful, which is why HIES will point people in the right direction.
What a good installer does when you complain
Hassan described the approach REST follows. Each complaint is logged and tracked from the start. The team asks for clear photos and details, offers remote troubleshooting where it can, and sends an engineer if it cannot. Urgent cases come first, such as no heating in winter or a vulnerable household. Complaint records are also checked in annual audits by the installer's regulators.
It helps if homeowners can describe the problem precisely. "It is not working" is hard to act on. "The hot water has been cold since Tuesday and the unit shows this error code" is much easier.
Is it a fault, or an expectation problem?
Many complaints turn out to be a gap between what the homeowner expected and what a heat pump does. A heat pump is not a gas boiler. It heats at a lower, steadier temperature, so you cannot come home, turn the thermostat up and expect a warm house within the hour. Running costs are another common source of disappointment. When prices rose in 2022, some customers who were told a heat pump would cost about £600 a year found it costing nearer £900, because the electricity price had changed. Estimates now state energy use in kilowatt hours, which makes that easier to understand.
The guests were clear that "unreasonable" is a risky word. If your bills are higher than the contract promised, that is a fair thing to raise. If the system was sized or designed badly, that is a genuine installation problem. If the installer simply never explained how to use it, a proper handover and a conversation about controls and schedules often fixes it.
How long after installation can you complain?
There is no fixed cut-off for asking questions. Hassan's view was that a customer should be able to come back after two, three or even four years, because learning to use a heat pump takes time. Workmanship guarantees, which for HIES members are insurance-backed, exist for exactly this reason. Cathryn also noted that statutory consumer rights run for six years, which can matter if a workmanship warranty has expired but a fault from the original work comes to light later.
How the HIES process works
According to Cathryn, HIES handles complaints in three stages. The first is informal: HIES contacts the customer, usually the same day, then contacts the installer with the details. At the time of the episode, HIES said the average complaint closed in under four days and that around 96 per cent were resolved at this stage without needing an ombudsman or court. If more is needed, HIES can arrange an inspection of the installation, which produces recommendations for putting it right. Evidence is the slow part: HIES needs to know what is actually wrong before it can ask an installer to act.
What compensation is realistic?
This depends entirely on the case. Cathryn's point was that wanting something is not the same as being entitled to it. Compensation usually has to be tied to a loss you can show, such as extra heating costs while the system was off, rather than the inconvenience of a late appointment. A missed visit that was rescheduled is rarely a compensation case. A month without heating and hot water in December is a different matter, and a good installer will recognise that without being asked. Sometimes an apology and a fix is all that is needed.
How common are complaints?
HIES said that between January and October 2024 it received more than 18,000 heat pump registrations on its portal and 80 complaints, which is under half of one per cent. It added that many were closed the same day, either because the installer was already dealing with the problem or because there was no real complaint. These are HIES's own figures for its members, so they say little about installers outside the scheme.
How to avoid a poor heat pump installation before you sign
Research the manufacturer. Check the warranty length, whether it covers labour as well as parts, and whether the company honours claims.
Check the installer, not just the price. Read reviews, ask for referrals from customers with the same product, and look at how long they have been trading. "If it is cheap, it is cheap for a reason" was the closing message.
Ask who checks the figures. Estimates of energy use and running costs should be independently validated. EPVS is one scheme that reviews the process an installer uses, and you can read about it on our accreditations page.
Look for real protection, not a row of logos. Ask what your deposit protection and workmanship guarantee actually cover, and who pays out if the installer stops trading.
Understand your payment protection. Both guests recommended paying at least part of the cost on a credit card or through regulated finance, because Section 75 of the Consumer Credit Act can make the card provider or lender jointly liable for purchases between £100 and £30,000. Check the detail with your card provider.
Finance is subject to status. REST UK acts as a credit broker, not a lender. This article summarises a podcast discussion for general information and is not legal or financial advice. Figures attributed to HIES are from the episode, recorded in 2024.