New Build EPC A Rating and Heat Pumps: What Developers Aren't Telling You Before You Exchange

New Build EPC A Rating and Heat Pumps: What Developers Aren't Telling You Before You Exchange

Last updated: 3 June 2026

You've reserved a new build, the sales brochure mentions an EPC A rating and a heat pump, and you're quietly pleased you won't be dealing with a boiler. Then you move in, the system makes a noise you weren't expecting, your electricity bill is higher than your old flat's gas bill, and nobody from the developer's office is picking up the phone. This scenario plays out on new build estates across the UK every month — and the frustration is almost always avoidable with the right information before you sign.

This article is for buyers who want to understand exactly what they're getting when a developer-installed heat pump comes with the keys, and for developers who need to understand what their obligations actually are. Because the regulatory landscape is shifting fast.

Why Every New Build Is Getting a Heat Pump Right Now

The short version: regulation is driving it. The Future Homes Standard mandatory compliance date means new builds must comply with dramatically tightened carbon emissions targets — and for the vast majority of new homes, that means ditching gas boilers entirely. The standard requires new residential builds to produce 75–80% fewer carbon emissions than those built to current regulations, and gas simply cannot get you there. Heat pumps, combined with high levels of insulation and mechanical ventilation heat recovery (MVHR), are the dominant solution developers are reaching for.

The UK government's commitment to an 87% cut in climate emissions by 2040 — signed into law in May 2026 — reinforces why this direction of travel is irreversible. Developers who had been hoping for a softening of the Future Homes Standard are now building to heat pump specifications whether they like it or not.

The result is that heat pumps are appearing in tens of thousands of new homes built by developers who have little institutional knowledge of how to commission them correctly, and being handed to buyers who have never operated one before. That combination creates predictable problems.

What "EPC A" Actually Means — and What It Doesn't Guarantee

An EPC A rating is an asset rating. It models the theoretical energy performance of a building under standardised occupancy assumptions. It tells you the home is well-insulated and uses a low-carbon heating system. What it does not tell you is how much you'll actually spend on energy bills, because that depends on how you use the system, what tariff you're on, and — critically — whether the heat pump was sized and commissioned correctly in the first place.

A heat pump running inefficiently in a poorly commissioned new build can deliver a Coefficient of Performance (CoP) of 2.0 or below. A well-installed and correctly operated heat pump in the same property should achieve 3.0–3.5, sometimes higher. That difference is enormous in practice: at 24p/kWh for electricity (a typical 2026 unit rate for many households), a CoP of 2.0 means you're paying 12p per unit of heat. At CoP 3.5, you're paying under 7p. Over a year of heating a three-bedroom new build, that gap can easily represent £400–£700.

The EPC A rating doesn't change based on which row you end up in. That's a fundamental limitation buyers rarely grasp until they've lived with the system for a winter.

New Build Heat Pump Problems: The Patterns That Keep Repeating

Common new build heat pump problems in the UK tend to cluster around the same root causes. Understanding them in advance puts you in a far stronger position when negotiating with a developer or seeking remediation after completion.

Incorrect flow temperature settings

Heat pumps are designed to run at low flow temperatures — typically 35–45°C — to operate efficiently. Many developer-installed systems arrive set at 55°C or higher, mimicking a gas boiler's behaviour. The system heats the home, but the CoP collapses. Buyers assume this is normal. It isn't.

Undersized or mismatched radiators

At lower flow temperatures, radiators need to be larger to emit the same heat output. Some developers use standard radiator specifications and then set the flow temperature higher to compensate — which is exactly backwards. The result is a system fighting itself.

No occupant handover

A heat pump operates differently from a gas boiler. It should run for longer periods at lower intensity, not be switched on and off like a boiler. Without a proper handover session — ideally 30–60 minutes with a qualified engineer walking through the controller — buyers default to familiar boiler behaviour and get poor results.

Warranty grey areas

Heat pump warranty in new builds sits in a complicated space between manufacturer warranty (typically 5–7 years on the unit itself), developer snagging responsibility (usually two years under NHBC Buildmark), and the installer's workmanship guarantee. When something goes wrong, each party points at the other. Buyers who haven't documented the commissioning data at handover are in the weakest position to challenge any of them.

Developer-Installed Heat Pumps vs Retrofit: Why the Starting Point Matters

The heat pump new build versus retrofit difference is significant, and mostly in the new build buyer's favour — provided the installation is done correctly. Retrofit heat pumps face the challenge of working with existing pipe sizes, radiator outputs, and insulation levels that were never designed with low-temperature heating in mind. New builds start with a blank canvas: correct pipe sizing, appropriate radiators, high insulation values, and no legacy infrastructure to work around.

This means a new build heat pump should, in theory, outperform a retrofit every time. When it doesn't — when buyers are reporting worse bills than neighbours in older semi-detached houses with gas boilers — that's almost always a commissioning or settings failure, not an inherent limitation of the technology.

If you're comparing heat pump options for a self-build or conversion project, our guide to air source heat pump models and specifications breaks down the units most commonly specified in new residential builds.

The Boiler Upgrade Scheme: Does It Apply to New Builds?

Here's where many buyers get tripped up. The Boiler Upgrade Scheme — which currently offers a £7,500 grant towards the cost of an air source heat pump — is explicitly designed for replacement installations in existing properties. New builds where a heat pump is the original heating system do not qualify. The developer absorbs the installation cost, which is why some developers advertise the EPC A rating and the heat pump as a selling point without ever mentioning the grant doesn't flow to the buyer.

However, if you're purchasing a new build specifically to replace a property that had a different heating system — or if you're a self-build buyer specifying your own installation — the eligibility picture changes. Our dedicated page on the Boiler Upgrade Scheme eligibility and application process has the current rules and the documentation your installer will need.

What does matter for new build buyers is that any heat pump installation should be carried out by an MCS-certified installer or business. MCS (Microgeneration Certification Scheme) certification is the industry standard that verifies the installer has been assessed against defined competency criteria and that the installation meets technical standards. It's the basis on which any future warranty claim, grant application on a future move, or dispute with a developer will be assessed. Always ask your developer for the MCS certificate at handover — it should be handed over as a matter of course alongside the building control completion certificate.

Questions to Ask Your Developer Before You Exchange

Most buyers treat the heat pump as an afterthought compared to kitchen specifications and flooring upgrades. That's understandable — it's invisible infrastructure — but it's where the real long-term financial exposure sits. These questions should go to the developer's technical team, not the sales office:

• What is the heat pump model and manufacturer, and what warranty does the manufacturer provide?
• Who is the MCS-certified installer, and can I have their contact details and the commissioning sheet?
• What flow temperature has the system been set to at commissioning, and is this confirmed in writing?
• Has a heat loss calculation been carried out for the specific plot, and were the radiators sized to that calculation?
• What occupant handover will be provided, and by whom?
• Under the developer's snagging warranty, what constitutes a heat pump defect versus a user error?

The honest answer is that most volume developers don't have clean answers to all of these questions — and the ones who do are almost always the ones whose buyers end up satisfied.

What New Build Buyers Should Do in the First Three Months

Once you've moved in, the clock on your snagging period starts. Here's how to protect yourself:

First, note the current meter readings and the heat pump's reported CoP from the controller display on day one. Most modern heat pumps — Vaillant, Daikin, Mitsubishi, Grant — have energy monitoring built into their controllers. Screenshot it weekly for the first month. If the CoP is consistently below 2.5 during heating season, something is wrong and you have documented evidence to raise with the developer.

Second, don't touch the settings in ways you don't understand. The temptation to boost the flow temperature when you feel cold is natural, but it masks the underlying problem rather than fixing it. Request an engineer visit instead.

Third, get an independent assessment if the developer is unresponsive. An MCS-certified engineer who didn't install the system can produce a report on commissioning quality and system settings. That report carries weight in dispute resolution.

If you're at the stage of comparing installers for a self-build, a plot purchase where you're specifying your own system, or a remedial installation, get quotes from MCS-certified engineers in your area — the comparison is free and the installers are vetted.

Frequently Asked Questions

Can a developer's heat pump installation fail its MCS certification after the fact?

Yes. MCS certification covers the installer's competency and the installation process, but it doesn't guarantee the system was commissioned correctly. If a post-installation check by an independent engineer finds the flow temperatures were set inappropriately or the system wasn't balanced, the commissioning certificate can be challenged. This is relatively rare but does happen on large volume developments where one installer is commissioning dozens of units under time pressure.

Who is responsible for heat pump warranty in a new build — the developer or the manufacturer?

Both, in different ways. The manufacturer's warranty (typically 5–7 years, extendable on registration) covers component defects in the unit itself. The developer's snagging warranty covers the installation workmanship, usually for two years under schemes like NHBC Buildmark. If the unit fails because it was installed incorrectly — wrong pipe sizing, incorrect refrigerant charge — the manufacturer may reject the warranty claim and point to the installation. The developer is then liable. This is why documented commissioning data at handover is essential.

Will the Future Homes Standard affect homes currently under construction?

Homes with planning permission already granted before the Future Homes Standard's implementation date have some transitional protection, though this is complex and depends on the specific timeline of the development. New planning applications submitted after the compliance date will be subject to the full standard. Buyers purchasing off-plan on developments where construction hasn't started should check which regulatory regime applies to their specific plot.

Is there a practical difference between heat pumps from different manufacturers in a new build context?

Yes, and it matters more than many buyers realise. Some units have better native monitoring and controller interfaces — important for understanding your system's performance. Others have stronger cold-weather performance, relevant if you're in northern England or Scotland. Our air source heat pump comparison covers the models most frequently specified by UK developers, including efficiency ratings at low ambient temperatures.

Ready to Get It Right From the Start?

Whether you're a self-build buyer specifying your own heat pump installation, a new build purchaser who wants an independent assessment of what you've been handed, or a developer trying to ensure your installations meet the standards your buyers will expect — the next step is finding an MCS-certified installer you can trust.

Get free quotes from vetted MCS-certified heat pump engineers — compare prices, check credentials, and make sure your new build heating system performs the way the EPC A rating suggests it should.