New Build EPC A Rating and Heat Pumps: What Developers Don't Tell You Before You Sign

New Build EPC A Rating and Heat Pumps: What Developers Don't Tell You Before You Sign

Last updated: 12 July 2026

That EPC A certificate pinned to your new build's particulars could cost you an extra £1,200 a year in running costs if the heat pump behind it was specified badly — and most buyers only discover this after they've moved in. The EPC rating tells you the theoretical energy efficiency of the property. It says very little about whether the heat pump system serving it was designed, commissioned, and sized with any real care. These are two very different things, and conflating them is one of the most expensive mistakes new-build buyers make.

This article is written for people who either already own a new-build with a heat pump or are about to exchange contracts on one. It is also useful for developers trying to understand what is actually expected of them — particularly as 2026 brings the Future Homes Standard ever closer to full implementation.

Why EPC A Doesn't Automatically Mean a Well-Designed Heat Pump System

An EPC A rating means the property scores 92 or above on the Standard Assessment Procedure (SAP) scale. In a well-insulated new build with large radiators or underfloor heating and a properly sized air source heat pump, achieving this is entirely realistic. The problem is that SAP calculations are modelling exercises. They use assumed values for occupancy, heating behaviour, and system performance — not actual measurements from your specific home with your specific system.

A heat pump running at a coefficient of performance (COP) of 2.8 will look perfectly acceptable in a SAP calculation even if, in real-world winter conditions, it consistently drops to 1.9 because the flow temperature was set too high by the commissioning engineer, or because the distribution system was undersized for the heat pump's output. You still get your EPC A. The developer still sells the plot. You still pay the bills.

This disconnect between paper performance and real-world running costs is the central tension that buyers need to understand before they hand over a deposit.

The Future Homes Standard and What It Actually Requires From 2026 Onwards

The Future Homes Standard heat pump requirement UK 2026 has been the subject of considerable discussion among housebuilders over the past two years. In its final form, the Future Homes Standard mandates that new homes in England must be built to produce 75–80% fewer carbon emissions than homes built under pre-2021 regulations. In practical terms, this almost always means a heat pump — gas boilers will not meet the carbon intensity targets in new builds.

What the standard does not do is specify which heat pump brand, what flow temperature regime it must operate at, or how it must be commissioned. Nor does it mandate post-installation performance monitoring. So while the regulation is substantive and genuinely pushes developers away from gas, it does not, by itself, guarantee that the heat pump you inherit in your new home will run efficiently.

Developers installing heat pumps primarily to satisfy planning conditions and building regulations — rather than because they have deeply thought through whole-system heating design — is a pattern the industry has documented repeatedly since 2022. This is not a criticism of all developers. Many do excellent work. But the incentive structure does not universally reward long-term occupant satisfaction over short-term build cost.

Common Problems in Developer-Installed Systems: What Owners Actually Report

New build heat pump problems UK common issues tend to cluster around a small number of root causes, and they are worth naming directly.

Oversized or undersized units

Heat load calculations are sometimes done at a development level rather than per plot, particularly on mixed-housing estates. End-of-terrace properties with greater heat loss than mid-terrace equivalents can end up with units that cycle on and off too frequently, reducing efficiency and accelerating component wear.

High flow temperatures baked into settings

A heat pump running flow temperatures of 55°C or above is working considerably harder than one running at 40–45°C. Commissioning engineers sometimes set higher flow temperatures because it is a quick way to ensure the home feels warm during snagging. Nobody then corrects this once the buyer moves in. Occupants pay for the inefficiency for years.

Missing or inadequate controls

Weather compensation controls — where the heat pump adjusts its output based on outdoor temperature — can improve real-world efficiency by 15–20%. Not all developer-installed systems include them, or enable them by default.

Incomplete handover documentation

Buyers frequently report receiving no meaningful explanation of how to operate their heat pump system. The MCS (Microgeneration Certification Scheme) requires that MCS-certified installers provide a system handover that includes operating instructions and performance documentation. When a developer uses a large-scale contractor rather than a dedicated MCS-certified installer for each plot, this handover process can become perfunctory. MCS certification exists precisely because the quality gap between a well-commissioned and a carelessly commissioned installation is enormous.

Heat Pump New Build vs Retrofit: Why the Starting Point Matters

Understanding the heat pump new build vs retrofit UK difference is important context for anyone comparing notes with friends or family who have installed heat pumps in older properties.

In a retrofit, every decision — emitter sizing, pipe layouts, cylinder placement — has to work around an existing structure. This makes the design process more complex and often more expensive. But it also tends to mean the installer thinks carefully about every element, because there is no pre-existing template to follow.

In a new build, the heat pump is specified during the design phase, and in principle, everything can be optimised from the start. Underfloor heating is far easier to install before the slab is poured. Radiators can be correctly sized from day one. Cylinder cupboards can be properly dimensioned. The theoretical advantages are real.

The honest answer is that new builds done well produce better heat pump outcomes than retrofits done well — but new builds done carelessly produce worse outcomes than retrofits done carefully, because the problems are often hidden in the structure and harder to fix later.

If you want to compare air source heat pump specifications across different models and manufacturers before your developer installs one, our air source heat pump comparison tool is a useful starting point.

Developer Responsibility, Warranties, and What You Can Actually Enforce

Heat pump warranty new build UK developer responsibility is an area where buyers have more leverage than they often realise — but only if they understand the structure.

Most new-build heat pumps come with a manufacturer's warranty of between two and seven years, depending on brand. Some manufacturers (Vaillant, Mitsubishi, Samsung) offer extended warranties of up to ten years on certain product lines. However, these warranties typically carry conditions: annual servicing by a qualified engineer, no unauthorised modifications, and registration within a specified period after installation. Annual servicing protects your warranty and efficiency, and failing to arrange it — even once — can provide a manufacturer with grounds to limit warranty coverage.

Developer responsibility sits separately. Under the Consumer Rights Act 2015 and the NHBC Buildmark warranty (which most new builds carry), structural defects and issues with primary services including heating systems are covered for varying periods. If your heat pump was installed incorrectly and this can be demonstrated — perhaps through an independent MCS assessment or energy monitoring data showing performance significantly below the modelled SAP figure — you may have grounds for a developer to rectify the installation.

What to check at handover

Ask for the MCS certificate for your specific plot's installation. Ask for the heat load calculation used to size the heat pump. Ask what flow temperature the system has been set to, and why. Ask whether weather compensation is enabled. These are not unreasonable questions, and a developer or contractor who cannot answer them is a warning signal.

The Cost Reality: What New-Build Heat Pump Owners Actually Spend

Electricity in 2026 sits at approximately 24–25p/kWh on a standard tariff, though EV and heat pump tariffs from providers like Octopus and E.ON can reduce this to 15–19p/kWh overnight. A well-commissioned heat pump on an off-peak tariff in a properly insulated new build is, in energy cost terms, broadly competitive with gas. A poorly commissioned one on a standard tariff is not.

Grants Available for New Builds — and Why They're Complicated

The Boiler Upgrade Scheme — which offers £7,500 towards an air source heat pump installation — is one of the most significant government incentives currently available. However, it is explicitly designed for existing homes replacing fossil fuel systems. New builds that are being built with heat pumps as the primary heating system from the outset are not eligible for the BUS grant.

This is a source of considerable frustration for buyers, who sometimes see neighbours in older homes receiving £7,500 of government support for an installation that cost them nothing at handover. If you are retrofitting a heat pump to replace a system in an older property, the full BUS grant eligibility criteria are worth checking carefully — the rules have been adjusted several times since the scheme launched.

For new-build buyers, the financial case for heat pumps rests on reduced running costs (when the system is properly designed), lower maintenance costs over time compared to gas boilers, and future-proofed carbon compliance rather than a direct government subsidy.

Before You Exchange: A Practical Checklist for New-Build Buyers

There are several concrete steps worth taking before you commit.

First, ask the developer which heat pump brand and model is being installed on your specific plot. Look it up. Check its Seasonal Coefficient of Performance (SCOP) rating, which is a more meaningful efficiency figure than the headline COP. An SCOP of 3.0 or above at the design conditions for your area is a reasonable minimum expectation in a new build.

Second, ask whether the radiators or underfloor heating circuits have been sized for low-temperature operation — ideally a flow temperature of 45°C or below. If the developer's spec sheet references 55°C or 60°C flow temperatures, this is a yellow flag. It may indicate a system designed for reliability during snagging rather than efficiency during occupation.

Third, confirm that the installer holds MCS certification. This is not a bureaucratic nicety. MCS-certified installers are bound by quality standards that non-certified contractors are not. An MCS installation certificate also provides you with documentation you can use if you need to make a warranty or insurance claim.

Fourth, ask specifically about the controls included and whether weather compensation is enabled by default.

If you want to compare quotes from MCS-certified installers for a second opinion on your new-build system, or if you are thinking about upgrading or adjusting your existing installation, get quotes from qualified installers through our comparison service.

Frequently Asked Questions

Can I replace the developer-installed heat pump if I'm unhappy with it?

Yes, but it is rarely the first option to pursue. Replacement costs between £8,000 and £14,000 depending on the system. Before replacing, commission an independent assessment of your existing installation — many apparent heat pump failures are actually commissioning or controls issues that can be corrected for a few hundred pounds. If the unit is demonstrably defective and within the developer's liability period, a replacement should be at their cost.

Does the Future Homes Standard apply to homes bought before 2026?

No. The Future Homes Standard applies to new homes built under planning permissions granted from the effective implementation date. Homes already built, and those under construction with pre-existing planning permission, are subject to the Part L 2021 regulations that preceded it. If you bought in 2023 or 2024, your home was built to transitional standards, not the full Future Homes Standard.

Why does my new-build heat pump make more noise than I expected?

Outdoor unit noise is an increasingly common complaint, particularly on densely built estates where units are placed close to neighbours' boundaries or bedroom windows. Permitted Development rules in England require that heat pump units do not exceed 42dB at one metre from a neighbour's window or door. If yours exceeds this, it may be in breach of planning conditions and you should raise this with your developer and local planning authority.

Is a developer-installed heat pump review worth commissioning independently?

For most buyers, yes — particularly within the first twelve months. An independent commissioning check by an MCS-certified engineer typically costs £150–£300 and can identify flow temperature settings, controls configurations, and refrigerant charge issues that significantly affect running costs. The potential savings in energy bills over a year often exceed the cost of the check within a single heating season.

The Bottom Line for New-Build Buyers

An EPC A certificate is a meaningful indicator of a well-designed building envelope. It is a poor indicator of whether the heat pump serving that building was installed with care, commissioned correctly, or will run efficiently over the years you live there. The Future Homes Standard is pushing all new builds towards heat pumps as the default heating system — which is the right direction of travel — but the quality of implementation is uneven and buyers bear the running cost consequences of that unevenness.

The questions to ask before you sign are specific ones about heat pump model, SCOP, flow temperature design, controls specification, and MCS certification. The developer may not always have good answers. That in itself is useful information.

If you want to check how your existing new-build heat pump compares, or you are looking at options for improving a poorly performing system, get quotes from MCS-certified installers who can assess and optimise your setup.