New Build EPC A Rating and Heat Pumps: What Developers Won't Always Tell You

New Build EPC A Rating and Heat Pumps: What Developers Won't Always Tell You

Last updated: 28 June 2026

Around £1,200 a year. That's what some new-build buyers are finding themselves paying to run a heat pump system that was sold to them — implicitly or explicitly — as an efficient, low-cost solution. Not because heat pumps don't work, but because the system installed by the developer was sized, configured, or commissioned poorly. An EPC A rating on a sales brochure does not guarantee a heating system that performs the way the brochure implies. This article is about understanding what you're actually getting, what the regulations now require, and how to protect yourself if you're buying or building new.

Why Every New Build Is Heading Towards a Heat Pump Whether Buyers Know It or Not

The Future Homes Standard heat pump requirement UK 2026 is now well within reach. The standard, which came into force for new residential properties in England from 2025 onwards, effectively bans gas boilers from new builds and mandates low-carbon heating. In practice, this means air source heat pumps in the vast majority of cases. Some larger developments are incorporating ground source systems or heat networks, but for a typical three or four-bedroom house, an air source unit outside the back of the house is the default solution developers reach for.

The EPC A rating that results from this approach is mathematically calculated based on the theoretical performance of the building and its heating system. It is not measured from your actual energy bills. That distinction matters more than most people realise when they're standing in a show home being told their new house will be cheap to heat.

The Difference Between a Heat Pump in a New Build and One in a Retrofit

This is genuinely one of the most important things to understand before either buying a new-build property or commissioning a system yourself. The heat pump new build vs retrofit UK difference is not just a technicality — it fundamentally changes how the system is designed and what performance you should expect.

In a retrofit, an installer is working around an existing property: existing radiators that may need upsizing, insulation that may be inconsistent, and a building that was never designed with low-temperature heating in mind. It is harder to get right. In a new build, the system should — in theory — be easier. The building fabric is modern, insulated to high standards, and often includes underfloor heating downstairs. The heat pump can be sized correctly for the actual heat loss of the property from the outset.

The problem is that developers are building at scale. A site of 200 homes might have a single specification for a heat pump system across multiple house types, with limited fine-tuning per plot. An installer comparing air source heat pump options for a private client will spend far more time on a single property's heat loss calculation than a developer's M&E contractor will on any individual unit.

Common New Build Heat Pump Problems UK Buyers Report

The new build heat pump problems UK buyers report most frequently are predictable once you understand the design pressures above. They include:

• Flow temperature set too high: Many developer-installed systems default to flow temperatures of 55–60°C or higher. This dramatically reduces efficiency. A well-designed new-build heat pump system running underfloor heating should operate comfortably at 35–45°C, delivering a Coefficient of Performance (COP) of 3.0 or above.
• Poor hot water cylinder sizing: Some developers install undersized unvented cylinders to cut costs. Households of three or more people regularly run out of hot water during morning routines.
• Incorrect refrigerant charge or pipework runs that are too long: These are commissioning and installation errors that reduce output and efficiency.
• Radiators not upsized where underfloor heating isn't fitted upstairs: Upstairs bedrooms with standard-sized radiators struggle to reach target temperatures at low flow temperatures.
• No proper handover or user guidance: Many buyers have no idea how to use the system correctly. Running a heat pump like a gas boiler — turning it on and off, cranking the thermostat — destroys efficiency.

These are not fringe complaints. The honest answer is that the developer-installed heat pump review UK picture, across forums, social media groups, and complaint data, is patchy at best and frequently poor. This is an industry-wide problem, not a single brand issue.

What an EPC A Rating Actually Means in Practice

The figures above assume the heat pump operates at the efficiency the SAP calculation assumes — typically a Seasonal Coefficient of Performance (SCOP) of around 2.5 to 3.0. If your developer has set flow temperatures incorrectly, that SCOP could fall to 1.8 or lower, at which point your running costs approach — or in some cases exceed — what a gas boiler would have cost. The EPC A rating does not update itself when the system is misconfigured.

Developer Responsibility, Warranties, and Who Picks Up the Bill

Understanding the heat pump warranty new build UK developer responsibility picture is essential before you exchange contracts. Most heat pump manufacturers offer a standard two-year parts and labour warranty, with extended warranties of five to seven years available if the unit is registered within 30 days of installation. Some manufacturers — Vaillant, Daikin, and Mitsubishi Electric among them — offer longer warranties on condition of annual servicing by a qualified engineer.

Here's where new-build buyers often fall through a gap. The developer arranges installation, but by the time you move in, the unit may already be partially through its warranty period. You need to ask, specifically:

• When was the heat pump unit installed and commissioned?
• Has it been registered with the manufacturer?
• Is the extended warranty in place, and in whose name?
• Who is responsible for defects under the NHBC Buildmark warranty versus the manufacturer's warranty?

Annual servicing protects your warranty and efficiency — this is not a marketing point but a contractual one with most manufacturers. Missing a service can void extended warranty cover. Make sure you understand who is responsible for arranging this in year one.

Under NHBC Buildmark, structural defects are covered for ten years, but heating system performance issues often fall into a grey area. Developers have been known to argue that a heat pump is performing to specification even when running costs are double what buyers expected. Getting anything in writing before completion — including expected running costs in £ per year — is worth doing.

MCS certification matters here too. Any installer working on a system that might be eligible for government grants, or that needs to meet Future Homes Standard compliance, should be MCS-certified. MCS (Microgeneration Certification Scheme) sets the quality and design standards that installations must meet. If your developer used a non-MCS installer, not only is grant eligibility compromised — the Boiler Upgrade Scheme grant of £7,500 requires MCS certification — but you also have less recourse if the system underperforms.

The BUS Grant Situation for New Builds

The Boiler Upgrade Scheme (BUS) grant of £7,500 is available for heat pump installations in England and Wales, but it does not apply to new builds. The scheme is specifically designed for replacing existing fossil fuel heating systems, and a brand new property with no prior heating system simply does not qualify. This is a frequent point of confusion. If you're buying a new build, you won't receive a £7,500 government contribution — the developer has absorbed (or not) those costs in the build price.

Where the BUS grant becomes relevant to new-build buyers is if they later move to an older property, or if they're a self-builder or custom builder completing a conversion project where an existing heating system is being replaced. In that specific scenario, checking eligibility through the Boiler Upgrade Scheme eligibility criteria is worthwhile before installation.

What to Check Before Buying a New Build with a Heat Pump

If you're in the process of purchasing a new-build property, these are the practical things to verify — ideally before exchange:

Documentation

Ask for the heat loss calculation for your specific plot, the heat pump model number and rated output, the design flow temperature, and the commissioning sheet. A developer who can't or won't provide these documents is a developer whose heating system you should be cautious about.

System Design

Check whether the property has underfloor heating throughout or just on the ground floor. If radiators are used upstairs, confirm they have been sized for the intended flow temperature. Ask whether a buffer tank or thermal store is included, and why or why not.

Cylinder Capacity

For a four-person household, a 200-litre minimum cylinder is the general benchmark. Anything significantly below this warrants a conversation with the developer.

Smart Controls

Modern heat pump systems perform far better with weather compensation enabled. Confirm the controls package includes this functionality and that it has been configured — not just installed and left at factory defaults.

If you are already in a new-build property and suspect the system is underperforming, commissioning an independent heat pump assessment from an MCS-certified engineer is a sensible first step. Get quotes from qualified local heat pump engineers to find someone who can assess and, where necessary, recommission your system correctly.

Frequently Asked Questions

Does a new build automatically get an EPC A rating if it has a heat pump?

Not automatically, but in practice most new builds meeting Future Homes Standard requirements and fitted with an air source heat pump will achieve EPC A. The rating depends on the full SAP assessment including insulation levels, glazing, air tightness, and the heat pump's assumed efficiency — not just the presence of the unit itself.

Can a developer install a heat pump that doesn't meet Future Homes Standard requirements?

Future Homes Standard-compliant builds must use low-carbon heating, but the specific system choice sits with the developer. What's required is that the dwelling achieves the performance targets set out in the standard — typically a 75–80% reduction in carbon emissions compared to the pre-2021 baseline. An air source heat pump in a well-insulated building is the most common way to meet this, but heat networks and ground source systems also qualify.

Who is responsible if my new-build heat pump runs up unexpectedly high energy bills?

This is genuinely complex. If the system has been installed incorrectly or commissioned with inappropriate settings, you may have a claim against the developer under the Consumer Rights Act or through the NHBC resolution service. If the system is functioning as installed but was simply designed poorly, the legal position is more difficult. Independent engineering evidence of poor design is the strongest foundation for any complaint.

Is the heat pump in my new build the same quality as one I'd buy independently?

The underlying unit may be from the same manufacturer range, but developer-procured systems are often specified to a price point. Extended warranties, premium controls packages, and higher-efficiency models are sometimes substituted for more basic equivalents. Checking the exact model number against current manufacturer specifications is a useful exercise.

Making Sure Your New-Build Heat Pump Works as Promised

An EPC A rating is a good starting point, but it is not a guarantee of low running costs or trouble-free performance. The gap between the theoretical efficiency modelled in a SAP calculation and the real-world performance of a developer-installed system can be significant — and closing that gap requires active engagement from you as the buyer, not passive trust in the brochure.

Ask the difficult questions before you exchange. Get the commissioning documents. Understand your warranty terms. And if you are in any doubt about the performance of your system, speak to a qualified, MCS-certified engineer who can assess it independently.

Whether you're in a new build or considering your options as a self-builder, getting quotes from vetted local heat pump specialists gives you comparative insight into what a well-designed system should cost to run — and whether yours is measuring up.