New Build EPC A Rating and Heat Pumps: The Costs, Risks and Realities Developers Won't Always Tell You

New Build EPC A Rating and Heat Pumps: The Costs, Risks and Realities Developers Won't Always Tell You

Last updated: 10 May 2026

A £400-a-year heating bill sounds like a dream — until you realise the heat pump delivering it was installed by the developer's cheapest subcontractor, set to the wrong flow temperature, and covered by a warranty that quietly expires the moment you try to claim on it. That gap between the EPC A certificate on your new build brochure and the lived experience of heating your home is exactly what this article addresses.

New builds in England are now overwhelmingly being delivered with air source heat pumps as the default low-carbon heating system. The push is regulatory, commercial and in many respects logical. But buyers who treat the EPC A rating as a guarantee of performance — rather than a theoretical benchmark — are setting themselves up for a rude awakening.

Why Almost Every New Build in 2026 Has a Heat Pump

The Future Homes Standard heat pump requirement UK 2026 is the single biggest driver of what you'll find installed when you collect your keys. Under the revised Building Regulations Part L, new homes must produce significantly fewer carbon emissions than those built to previous standards, and for most developers, an air source heat pump paired with high levels of insulation is the cleanest route to compliance.

The result is a near-universal shift. Barratt Developments, Taylor Wimpey and Persimmon have all reported the majority of their new completions in England now feature heat pumps rather than gas boilers. For buyers coming from older homes, this is a genuine shift in how domestic heating works — and the EPC A certificate doesn't prepare you for that transition.

An EPC A rating means the property has been calculated to have excellent energy efficiency under a standardised assessment. That assessment assumes specific usage patterns, a fixed tariff relationship, and crucially, a correctly operating system. It is a modelled figure, not a meter reading. The actual energy consumption in your home will depend on how the system has been configured, your flow temperature settings, and whether the installer bothered to commission the unit properly.

The Heat Pump New Build vs Retrofit Difference Nobody Explains at the Sales Office

When people argue about whether heat pumps "work", they are often conflating two very different contexts. The heat pump new build vs retrofit UK difference is substantial, and it matters enormously when setting expectations.

A retrofit installation into an older semi-detached house requires careful sizing, possible radiator upgrades, and often a degree of compromise. A properly designed new build, on the other hand, should be ideal territory for a heat pump. The fabric is airtight, the insulation is thick, the radiators are sized correctly from the outset, and the system is designed around low flow temperatures — typically 35°C to 45°C rather than the 70°C-plus that old boiler systems ran at.

In theory, then, new build buyers are in the best possible position. The honest answer is that many of them still end up with poorly performing systems because the developer treated the heat pump as a compliance box to tick rather than a heating system to design carefully. Undersized units, incorrect refrigerant charges, and radiators that were specified on paper but never checked against the actual room heat loss calculations are common failure points.

If you want to understand how these systems compare across different property types and manufacturers before you accept what the developer has chosen, the air source heat pump comparison tool on this site gives you a clearer picture of what the market actually offers.

New Build Heat Pump Problems UK: What Buyers Actually Report

New build heat pump problems UK homeowners describe most frequently fall into three categories: noise, control complexity, and running costs that don't match expectations.

Noise

The external unit on an air source heat pump contains a fan and compressor. In a well-planned development, it's positioned away from bedrooms and living spaces. In a hurried development where the plot layout changed three times before completion, it's sometimes directly beneath a bedroom window. Planning guidance and MCS (Microgeneration Certification Scheme) installation standards both address this, but compliance varies. MCS certification matters here because it's the scheme that sets out minimum standards for sizing, positioning and commissioning — and only MCS-certified installers can sign off work that qualifies for government schemes. If your developer used a non-MCS installer, that's a red flag worth pursuing.

Controls and Thermostat Confusion

Heat pumps operate most efficiently when run continuously at a low level rather than turned on and off like a boiler. Many new build buyers arrive from gas-heated homes and immediately start adjusting the thermostat aggressively, which can spike electricity consumption and reduce the system's coefficient of performance. Developer handovers often last twenty minutes and cover the kitchen appliances, the alarm code and the window locks — not a proper explanation of weather compensation curves.

Running Costs That Don't Match the EPC

With electricity at around 24p/kWh and gas at approximately 6p/kWh in 2026, the economics of a heat pump depend entirely on its efficiency — its Seasonal Coefficient of Performance (SCOP). A well-installed unit might achieve an SCOP of 3.5, meaning you get 3.5 units of heat for every unit of electricity consumed, bringing the effective cost per unit of heat to around 6.9p/kWh. A poorly installed unit running at an SCOP of 2.0 costs you 12p/kWh for heat — materially more expensive than gas.

The table above makes the stakes clear. A well-installed heat pump in a new build is genuinely competitive with gas. A poorly installed one is not.

Developer Installed Heat Pump Review UK: How to Assess What You've Inherited

When reviewing a developer installed heat pump, the first step is to locate the commissioning documentation. Every heat pump installation should come with a commissioning sheet signed by the installer, confirming that the refrigerant charge is correct, the flow temperature has been set appropriately, and the system has been balanced. If the developer cannot produce this document, push back formally in writing.

Check the make and model. Most large developers in the UK use units from Vaillant, Daikin, Samsung or Mitsubishi Electric. These are reputable brands — the issue is rarely the hardware, it's the installation and configuration. Look up your unit's specification and cross-check the installed capacity (in kW) against your property's calculated heat loss. A four-bedroom detached new build typically has a heat loss of 6–10 kW. If the installed unit is rated at 5 kW, that's worth querying.

Also check the hot water cylinder size. Heat pumps heat domestic hot water more slowly than a boiler. A 200-litre cylinder is a reasonable minimum for a four-person household; anything smaller may mean you run out of hot water in the morning.

Heat Pump Warranty New Build UK: Who Is Actually Responsible

Heat pump warranty new build UK situations are complicated by the layered nature of developer, installer and manufacturer responsibilities. The manufacturer's warranty on the heat pump unit itself — typically five to seven years from leading brands, sometimes extendable to ten — runs from the date of installation, not the date you moved in. If the property sat empty for six months after handover while you waited for your mortgage to complete, that's time off your warranty clock.

The developer, meanwhile, carries obligations under the NHBC Buildmark warranty (or equivalent), which covers structural defects for ten years. Heating system failures are covered under the first two years if they result from defective workmanship or materials. After that, you're relying on the manufacturer.

Annual servicing protects your warranty and efficiency — most manufacturers require documented annual service records to honour warranty claims in the latter years of coverage. This is not small print to ignore.

If you're planning to buy a new build and want a second opinion on whether the installed system is appropriate before exchange, it's worth getting an independent heat pump assessment. You can use the free quotes tool to connect with MCS-certified engineers in your area who can assess an existing installation as well as quote for new work.

The BUS Grant: Does It Apply to New Build Buyers?

This is one of the most frequent questions new build buyers ask — and the answer is almost always no. The Boiler Upgrade Scheme (BUS grant), which offers £7,500 towards an air source heat pump, is designed for existing homes replacing fossil fuel heating systems. New build properties are explicitly excluded because the heat pump is treated as the primary system from the outset, not a replacement for anything.

However, if you're buying a new build and the developer has offered you the option to specify a gas boiler instead, and you want to pay extra to have a heat pump installed — that scenario is worth exploring with a specialist, because the eligibility rules are nuanced. You can read more about the full scheme eligibility on the Boiler Upgrade Scheme grant page.

For developers themselves, and for buyers of new homes who later want to upgrade the installed system, the grant landscape may evolve further under the Future Homes Standard implementation, which continues to be phased in through 2026 and beyond.

What to Ask Your Developer Before You Exchange

Armed with the information above, there are concrete questions worth raising with your developer before you commit:

• Who installed the heat pump — are they MCS certified?
• Can you provide the full commissioning documentation for the heat pump and hot water system?
• What is the unit's rated capacity, and does it match the calculated heat loss for this plot?
• What size is the hot water cylinder, and what is the standing heat loss figure?
• What flow temperature has the system been commissioned at, and is weather compensation enabled?
• When does the manufacturer warranty begin — installation date or handover date?
• Is there a handover pack including operating instructions and recommended service intervals?

A developer who struggles to answer these questions is not a developer whose heating specification you should accept without scrutiny.

Frequently Asked Questions

Does a new build EPC A rating guarantee low heating bills?

No. The EPC A rating is a modelled energy performance score based on standardised assumptions. Your actual bills depend on how the heat pump has been installed, configured and used. A poorly commissioned system can produce bills significantly higher than the EPC suggests.

Who is responsible if the developer-installed heat pump stops working in year three?

In year three, the NHBC two-year defects period will have expired for most new builds. You'd be relying on the manufacturer's warranty — provided it's still valid, which typically requires annual service records. The developer's liability is limited unless you can demonstrate the failure resulted from a defect present at the time of handover.

Can I get the £7,500 BUS grant on a new build?

Generally no. The Boiler Upgrade Scheme is intended for replacing fossil fuel systems in existing homes. New build properties with a heat pump installed as the primary system from construction are not eligible under the current rules.

Is the Future Homes Standard already in force in 2026?

The Future Homes Standard is being implemented in stages. The 2025 uplift to Part L of the Building Regulations has already significantly tightened new build carbon requirements, making heat pumps the default practical solution for most developers. The full Future Homes Standard is expected to be in force for new applications from late 2026 onwards, though the regulatory trajectory is clear: gas boilers in new builds are effectively finished.

Getting Independent Advice Before You Commit

New build buyers are in a structurally weaker position when it comes to heating system specification than they realise. The developer chose the heat pump, the installer, the flow temperature and the cylinder size — and the EPC A certificate will look identical whether those choices were excellent or merely adequate.

If you're buying a new build, considering a developer's specification, or you've already moved in and something feels off about your heating costs or performance, getting an independent assessment from a qualified MCS-certified installer is the most practical step you can take. Use the get quotes tool to connect with engineers in your area — it's free to use, and you're under no obligation.