New Build EPC A Rating and Heat Pumps: Why Your Energy Bills Could Still Surprise You

New Build EPC A Rating and Heat Pumps: Why Your Energy Bills Could Still Surprise You

Last updated: 31 May 2026

Some new-build buyers open their first winter energy bill expecting near-nothing and find it running to £180 or more for a single month — despite owning a brand-new EPC A-rated home with a heat pump already installed. That gap between expectation and reality is precisely what this article is about. An EPC A rating is a genuine achievement in building efficiency, but it does not automatically mean your heat pump has been set up correctly, sized appropriately, or that you know how to run it in a way that keeps bills where the brochure implied they would be.

What an EPC A Rating Actually Tells You — and What It Doesn't

An EPC A rating means your home scores 92 or above on the Standard Assessment Procedure (SAP), the government's modelling framework for residential energy performance. For new builds completed since 2022, hitting that threshold almost always requires a low-carbon heating system — in practice, a heat pump. The SAP model credits heat pumps heavily because of their coefficient of performance (CoP): a well-operating air source heat pump can deliver 3 units of heat for every 1 unit of electricity consumed, which looks excellent in a calculation that benchmarks against gas.

What the EPC does not tell you is whether the system was commissioned properly, whether the radiators or underfloor heating circuits are sized to run at the low flow temperatures a heat pump needs, or whether anyone explained to you that a heat pump should run differently from a gas boiler. These are not trivial gaps. They are the source of most of the frustration that shows up in developer installed heat pump reviews across the UK.

The Future Homes Standard Is Already Reshaping What Gets Built

The Future Homes Standard heat pump requirement in the UK comes into force in 2026, requiring all new residential properties to produce at least 75–80% fewer carbon emissions than those built to 2013 Part L regulations. In practice, this means heat pumps (or occasionally heat networks) become the default for new builds rather than the exception. Developers who were previously installing gas boilers as standard have been accelerating their switch ahead of the deadline, which has created a pipeline of homes where the technology is installed but installer training and homeowner education have not always kept pace.

This is not a criticism of heat pumps themselves. It is an observation about the speed of a transition that the construction industry has been managing while simultaneously dealing with planning pressures, materials costs, and labour shortages. The Future Homes Standard is the right policy direction — the execution at site level is where the variation creeps in.

New Build Heat Pump vs Retrofit: Understanding the Fundamental Difference

The heat pump new build vs retrofit difference matters enormously for how you think about your system. In a retrofit scenario, an MCS-certified installer surveys your existing home, calculates heat loss room by room, and designs a system around what's there — often recommending radiator upgrades or adding underfloor heating to make low-temperature operation viable. The homeowner is involved at every stage and typically receives a detailed handover.

In a new build, the heat pump is selected and installed as part of a volume housebuilding process. The home is designed around it from the start, which is the good news — flow temperatures and emitter sizing should theoretically be correct from day one. The complication is that "should be" and "is" diverge more often than developers would like to admit. Snag lists for new builds frequently include items like heat pump settings locked at 55°C flow temperature when the system was designed for 45°C, or buffer tanks not plumbed in correctly, or weather compensation curves set to default values that suit nobody's climate zone in particular.

If you are comparing your options before purchasing, our air source heat pump comparison pages show how different models perform across a range of building types — which is worth reading even if your developer has already chosen a unit, since it gives you context for what the specification sheet should show.

Common Problems Reported With Developer-Installed Systems

New build heat pump problems in the UK that come up repeatedly include the following:

• Incorrect flow temperature settings: Many units are handed over running at 55°C, which is a gas-boiler mindset applied to a heat pump. At that setting, efficiency drops sharply. The correct setting depends on your heat loss calculation and emitter size — often 40–45°C for a well-insulated new build.
• Hot water cylinder scheduling: Developer handovers frequently leave the domestic hot water reheat cycle running far too often, or at unnecessarily high temperatures for Legionella protection. Both waste electricity.
• No weather compensation enabled: Weather compensation adjusts flow temperature automatically with outdoor conditions. It is one of the most impactful efficiency settings available and is often left disabled.
• Undersized or incorrectly zoned underfloor heating: In multi-storey new builds with a mix of UFH downstairs and radiators upstairs, the two circuits sometimes share a manifold temperature that suits neither optimally.
• Noisy siting: Acoustic planning conditions in some developments mean the outdoor unit ends up positioned where it bounces sound off adjacent walls or fences.

None of these issues are unfixable. But fixing them requires knowing they exist in the first place.

Developer Responsibility, Warranties, and What You Can Reasonably Expect

Heat pump warranty on a new build in the UK is a layered question. The unit itself typically carries a manufacturer's warranty of 2–5 years as standard, extendable to 7 or 10 years with registration or servicing conditions. The installation, however, is covered under the developer's NHBC Buildmark warranty (or equivalent), which provides a 10-year structural protection but handles mechanical systems somewhat differently — defects in the first 2 years are the developer's responsibility to fix, while years 3–10 cover major structural defects rather than mechanical performance.

This creates a practical window: if your heat pump is not performing correctly, the first two years after legal completion are your strongest period to compel the developer to act. Document everything — metering data, bill amounts, settings screenshots. Annual servicing protects your warranty and efficiency, and some manufacturers will void extended warranty cover if you cannot demonstrate a service record, so getting that first service done before the end of year one is worth prioritising regardless of how new the system feels.

MCS Certification and Why It Should Appear on Your Paperwork

MCS (Microgeneration Certification Scheme) certification is the quality standard that governs heat pump installation in the UK. Any heat pump installed by an MCS-certified contractor must follow a defined design and commissioning process, including a heat loss calculation, a system design record, and a handover pack for the homeowner. For new builds, the installing contractor should be MCS-certified and you should receive an MCS certificate as part of your completion documentation.

If you did not receive one — or cannot find it in your paperwork — contact your developer immediately. Without it, you may also find yourself unable to access grant funding should you ever need to replace the unit, since the Boiler Upgrade Scheme (which provides £7,500 towards qualifying heat pump installations) requires an MCS-certified installation as a condition of eligibility.

Running Costs in Practice: Real Figures for EPC A New Builds

The table below gives a realistic picture of annual running costs for a typical EPC A new-build using an air source heat pump, based on October 2025 to April 2026 tariff data and a 3-bedroom semi-detached with good fabric performance.

The numbers make a clear point: a heat pump running at its design conditions beats gas on both cost and carbon. A heat pump running at wrong settings costs more than gas and generates legitimate frustration. The technology is not at fault — the commissioning is.

Getting More From What's Already Installed: Practical Steps

If you have moved into a new build with a heat pump and are not sure whether it's running as it should, there are straightforward things to check before calling anyone out:

1. Find your controller or app and check the flow temperature setting. If it is above 50°C and your home has underfloor heating throughout, that is worth querying.
2. Check whether weather compensation is enabled. Most modern heat pump controllers have this as a toggle or a curve setting — the installer manual will confirm where to find it.
3. Look at your hot water schedule. Reheating a 200-litre cylinder to 60°C multiple times per day is rarely necessary. Once daily, with a Legionella cycle once a week, is typically sufficient.
4. Install a smart electricity monitor if you have not already. Knowing what the heat pump draws per day in winter baseline conditions tells you quickly whether something is off.

If issues persist or you are not comfortable adjusting settings yourself, get quotes from MCS-certified engineers who specialise in heat pump commissioning and optimisation — this is a different skill set from installation and worth seeking out specifically.

Frequently Asked Questions

My developer says the heat pump settings are correct but my bills are high — what can I do?

Request the original MCS commissioning certificate and design documentation from your developer. This should show the designed flow temperature, heat loss calculation, and expected seasonal performance. If the as-installed settings differ from the design, you have grounds to request a recommissioning visit. Keep copies of your energy bills as evidence.

Does the £7,500 Boiler Upgrade Scheme apply to new builds?

No. The BUS grant is available only to existing properties replacing fossil fuel heating — it cannot be applied to a heat pump already installed in a new-build property. If you were told otherwise, that is incorrect. The grant is, however, relevant if you ever move to an older property and want to install a heat pump there.

What is the Future Homes Standard and does it affect homes being sold now?

The Future Homes Standard comes into force in 2026 and applies to new-build homes receiving planning permission after the implementation date. If your home was built and completed before that date, it was built to the current Part L regulations — which already require very low carbon heating in practice. Any home sold from 2026 onwards that was built after the standard takes effect must meet the new requirements, which effectively mandates heat pumps as the primary heating solution.

Can I swap out my developer-installed heat pump for a different brand if I'm unhappy with it?

Technically yes, but it is rarely the right move in the first few years. The more practical path is to optimise what is installed, since most developer heat pump problems are configuration issues rather than equipment failures. If the unit is genuinely faulty within the first two years, the developer is obliged to repair or replace it under the NHBC warranty framework. Replacing it yourself at cost would only make sense if the unit is genuinely unsuitable and the developer refuses to act — at which point you would want independent MCS-certified advice before committing.

The Honest Answer on New Builds and Heat Pumps

The honest answer is that an EPC A rating is a structural achievement, not a guarantee of a well-optimised heating system. The fabric of modern new builds is genuinely excellent — high-specification insulation, triple-glazed windows in better developments, and airtightness that would have been impressive five years ago. The heat pump sitting within that fabric is capable of delivering very low running costs and meaningful carbon savings. But it needs to be set up for the building it is in, not left on default settings that were never adjusted after commissioning.

New-build buyers who take the time to understand their system in the first six months almost always end up with better outcomes than those who assume it just works. The technology rewards engagement — and if you need help from an expert who actually knows heat pumps rather than a general heating engineer, finding MCS-certified specialists through our quote tool is the most direct way to get there.