EPC A Ratings, Heat Pumps and New Builds: What Buyers and Developers Are Getting Wrong in 2026

EPC A Ratings, Heat Pumps and New Builds: What Buyers and Developers Are Getting Wrong in 2026

Last updated: 8 July 2026

You've just reserved a new-build home and the developer hands you a glossy folder — inside, a heat pump is listed as a "feature," your EPC shows an A rating, and the running costs look impressive on paper. Six months after moving in, the bills are higher than expected, the heat pump keeps alarming, and nobody is quite sure whose responsibility it is to fix it. This is not an unusual story. It's becoming a pattern across UK new-build developments, and understanding why it happens — before you sign — could save you thousands.

Why New Builds Are Almost Universally Getting EPC A Now

An EPC A rating on a new-build isn't an accident. It's a consequence of building regulations that have progressively tightened over the past decade, culminating in a set of standards that make fossil fuel heating systems increasingly difficult to justify on paper. The Future Homes Standard — mandatory for all new builds — makes heat pump requirement UK-wide the practical default by 2026, as gas boilers can no longer achieve the emissions targets needed for compliance. Developers aren't choosing heat pumps because they love the technology. They're choosing them because the regulations leave little room for anything else.

That distinction matters enormously for buyers. A heat pump installed to tick a compliance box is not the same as a heat pump installed to perform. The building can achieve EPC A on SAP calculations while being delivered with undersized emitters, inadequate insulation detailing around thermal bridges, or a heat pump unit that was specified by a procurement team rather than an experienced heating engineer.

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

The heat pump new build vs retrofit UK difference is substantial, and most homebuyers don't realise it until something goes wrong. In a retrofit, an experienced installer surveys the property, performs heat loss calculations, sizes the unit correctly, and usually upgrades radiators or installs underfloor heating to match the lower flow temperatures heat pumps operate at. In a new build, that process is often compressed into a procurement exercise where cost-per-unit and installation speed dominate the decision.

New builds do have genuine advantages — high fabric efficiency from day one, underfloor heating as standard in many developments, and no legacy pipework to contend with. But the assumption that a well-insulated new build automatically makes heat pumps easy is only half true. Poor commissioning, incorrect refrigerant charge, and flow temperature settings left too high are some of the most common new build heat pump problems UK homeowners report. These aren't faults with heat pump technology. They're faults with delivery.

Common Issues Reported by New-Build Heat Pump Owners

• High flow temperatures: Units set to 60°C+ rather than the 35–45°C optimal for heat pump efficiency, resulting in electricity bills far above estimates.
• Incorrectly sized buffer tanks or no buffer tank at all, causing short-cycling and premature compressor wear.
• Hot water not reaching the set temperature reliably, often linked to immersion heater backup being either misconfigured or absent.
• No handover training: Owners left with a system they don't know how to control, resorting to keeping it at full blast "just in case."
• Warranty disputes: Disagreements between developer, heat pump manufacturer, and installer about whose responsibility a defect falls under.

Developer Installed Heat Pumps: What Buyer Reviews Actually Reveal

Developer installed heat pump review UK feedback on property forums, consumer review sites, and social housing surveys tells a consistent story: the technology works when delivered properly, and creates significant frustration when it isn't. A 2025 survey by the Heat Pump Association found that satisfaction rates among new-build heat pump owners were notably lower than among retrofit customers — with the gap almost entirely explained by commissioning quality and post-installation support, not the heat pumps themselves.

The honest answer is that large national housebuilders have, in many cases, prioritised procurement efficiency over installation quality — and until regulation requires them to demonstrate ongoing performance rather than just theoretical EPC ratings, some will continue to do so. That said, there are developers doing this properly, and knowing what to look for puts you in a much stronger negotiating position.

Questions to Ask Before You Exchange

• Who installed the heat pump — an in-house team or a subcontractor? Are they MCS certified?
• Can you see the heat loss calculation for the plot?
• What are the warranted SPF (Seasonal Performance Factor) figures, and how were they estimated?
• Who is the warranty contact — the developer, the manufacturer, or both?

MCS certification matters here. MCS (Microgeneration Certification Scheme) sets minimum standards for heat pump design, installation, and commissioning. An MCS-certified installation on a new build is not a guarantee of excellence, but it is a guarantee that certain baseline requirements were met and documented. If a developer cannot confirm MCS certification for the heat pump installation, treat that as a serious red flag.

Heat Pump Warranty in New Builds: Whose Problem Is It?

Heat pump warranty new build UK developer responsibility is a genuinely murky area, and it catches buyers off guard. Most heat pump manufacturers offer a 5 to 10-year parts warranty — but that warranty may be conditional on annual servicing being carried out by an approved engineer, and on the installation meeting specific technical standards. If the developer's subcontractor installed the unit incorrectly, the manufacturer may decline warranty claims on those grounds.

Separately, new builds come with an NHBC Buildmark warranty (or similar) covering structural defects, but heating system performance sits in a grey zone. The developer is responsible for defects in the first two years under the Consumer Code for Housebuilders — but proving a heat pump is performing below specification requires metering data, which most buyers don't have access to from day one.

The practical advice: request the full commissioning documentation at handover, including flow temperature settings, refrigerant charge records, and the MCS certificate. Keep your own records of monthly electricity consumption from the first bill onwards. If performance deteriorates in year two or three, that data becomes evidence.

Running Cost Reality: What EPC A Actually Means for Bills

An EPC A rating does not mean cheap to run. It means the building performs well against a standardised calculation. Real-world running costs depend on occupant behaviour, the electricity tariff in use, the heat pump's actual Coefficient of Performance, and how the system has been configured.

The figures above illustrate something important: a poorly commissioned heat pump in an EPC A new build can cost almost as much as a gas boiler, while a well-commissioned system in the same building can be genuinely cheaper. The EPC rating doesn't determine your bills. The installation quality does.

For context, electricity in the UK currently sits around 24–25p/kWh under the standard tariff, while gas runs at approximately 6.5p/kWh. Heat pump tariffs from suppliers like Octopus and E.ON Next can reduce the electricity rate meaningfully — some heat pump tariffs offer rates as low as 15p/kWh overnight — but these need to be actively sought out, not assumed.

Grants and Incentives: What New-Build Buyers Can and Cannot Access

This is where new-build buyers frequently feel short-changed. The Boiler Upgrade Scheme — which offers £7,500 towards an air source heat pump — is available only for properties in England and Wales where the heat pump is being newly installed to replace a fossil fuel system. New builds with a heat pump already fitted at completion are not eligible. The developer absorbed (or didn't absorb) that cost before you arrived.

What this means practically: if you're comparing the cost of a new-build versus a self-commissioned retrofit where you could access the Boiler Upgrade Scheme £7,500 grant, factor in that the retrofit buyer has a meaningful financial advantage — provided the property is suitable. For new-build buyers, the benefit comes in the form of reduced specification costs rather than direct grant access.

If you're a developer reading this and still specifying heating systems for plots that don't yet have planning approval — the Future Homes Standard mandatory compliance position means any new build commencing after the 2026 implementation date must meet the uplift in fabric and carbon targets that effectively requires low-carbon heating. Specifying heat pumps now, and specifying them correctly with MCS-certified contractors, is no longer optional strategy. It's the baseline.

For those comparing options before committing — whether you're a buyer evaluating a development or a small developer specifying your first heat pump scheme — our guide to air source heat pump models and specifications covers the leading units currently used in UK new builds with independent performance data.

What Good Looks Like: Developer Practices Worth Seeking Out

Some developers — typically smaller regional builders and some of the more progressive national names — are genuinely doing this well. The markers are consistent: MCS-certified subcontractors under direct supervision, heat loss calculations per plot rather than per house type, underfloor heating throughout rather than just ground floor, and a structured handover process where a heating engineer walks owners through the controls before they collect the keys.

A few are going further: integrated smart controls with remote monitoring, pre-agreed servicing contracts for the first two years, and performance guarantees linked to actual SPF rather than theoretical EPC scores. These developments command a small premium, but the reduced risk of a troubled first winter — and the warranty clarity — often justifies it.

If you're ready to get independent advice on heat pump options for your new build, or you're a developer wanting MCS-certified quotes for a scheme, compare quotes from vetted MCS-certified installers here.

Frequently Asked Questions

Is a developer-installed heat pump automatically covered by the house warranty?

Not automatically, no. NHBC Buildmark and equivalent warranties cover structural defects. The heat pump itself is covered by the manufacturer's warranty, which is usually 5–7 years, and the developer is liable for defects under the Consumer Code in the first two years. These can overlap but they're not the same thing — and disputes about who covers what are common. Get the commissioning documentation at handover so you have a baseline to argue from.

Can I get the £7,500 BUS grant if my new build already has a heat pump?

No. The Boiler Upgrade Scheme is for replacing an existing fossil fuel system with a heat pump. New builds with heat pumps installed at construction are not eligible. The grant is a retrofit incentive, not a new-build one.

Why are my heat pump bills higher than the EPC estimated?

EPC calculations use standardised occupancy and temperature assumptions that rarely match real household behaviour. They also assume optimal system performance — which requires correct commissioning. If your flow temperature is set too high, or your heat pump is short-cycling due to incorrect buffer setup, your actual COP will be lower than the modelled figure, and bills will be higher accordingly. Get an engineer to check your system settings before assuming the heat pump itself is at fault.

What should I check about the heat pump before exchanging contracts on a new build?

Ask for the make and model of the heat pump, confirmation of MCS certification for the installation contractor, the heat loss calculation for the specific plot, and the commissioning checklist. Also ask who to contact if there are performance issues after year two — is it the developer, the manufacturer, or the installing subcontractor? If the developer can't answer that clearly, it's a sign their aftercare process needs scrutiny.

Ready to Get Independent Advice?

Whether you're a buyer trying to make sense of what a developer has installed, or a developer wanting properly specified heat pump quotes from MCS-certified contractors, independent comparison is the fastest way to get clarity. Avoid the most common mistakes before you commit — get quotes from MCS-certified heat pump installers across the UK and make an informed decision with real numbers, not brochure estimates.