New Build EPC A Rating and Heat Pumps: What Buyers Actually Need to Know Before Signing

New Build EPC A Rating and Heat Pumps: What Buyers Actually Need to Know Before Signing

Last updated: 15 July 2026

You've found a new build you like. The brochure mentions an EPC A rating, underfloor heating, and a heat pump — all described in warm, aspirational language somewhere between the kitchen island and the landscaped rear garden. What it doesn't explain is whether that heat pump will work properly, who's responsible if it doesn't, and what happens to your energy bills once you're actually living there. Those are the questions worth asking before you exchange contracts.

Why New Builds Are Being Built Around Heat Pumps Right Now

The shift isn't accidental. The Future Homes Standard — which makes low-carbon heating mandatory for new residential construction — is driving an industry-wide transition that developers can no longer sidestep. With the Future Homes Standard mandatory for new builds, compliance means no gas boiler options, full stop. Air source heat pumps have become the default solution for most volume housebuilders because they're cheaper to install than ground source alternatives and meet the fabric-and-systems requirements needed to achieve an EPC A.

The EPC A rating itself is relevant here in a specific way. New builds must hit a Standard Assessment Procedure (SAP) score of 92 or above to achieve an A. Heat pumps, when paired with good insulation, triple-glazed windows, and mechanical ventilation with heat recovery (MVHR), get developments over that line. Without the heat pump, most new builds land in the B bracket — which increasingly won't meet lender, planning, or regulatory requirements.

This is fundamentally different from the heat pump new build vs retrofit UK difference that often confuses buyers. In a retrofit situation, a heat pump is being inserted into an older, less efficient building — a much harder job requiring radiator upgrades, loft and wall insulation, and careful system design. In a new build, the heat pump is designed in from the start, with the fabric specification built around it. The result should be a genuinely efficient system. Whether it is in practice depends heavily on who designed it and how well it was commissioned.

The EPC A Promise: What It Means in Practice

An EPC A doesn't guarantee low bills. It indicates the dwelling's theoretical energy efficiency — based on modelled assumptions about occupancy, heating patterns, and system performance. Real-world energy use diverges from SAP predictions regularly, sometimes significantly.

The coefficient of performance (COP) you'll see marketed — often figures like 3.5 or 4.0 — means the heat pump produces 3.5 to 4 units of heat for every unit of electricity consumed. At current electricity prices of around 24–25p/kWh (as of mid-2026), that effective heating cost works out to roughly 6–7p/kWh of useful heat. Gas, by comparison, costs around 6–7p/kWh before boiler efficiency losses, which brings it closer to 7–8p/kWh delivered. The economics are more competitive than they were two years ago, but they still depend on the heat pump running at a high COP — which requires the system to be properly sized, properly commissioned, and running at low flow temperatures.

The figures above assume a well-insulated new build of approximately 90–110m² with low-temperature underfloor heating. Performance drops if flow temperatures are set too high — something that happens more often than it should when systems are set up by site engineers under time pressure rather than properly trained heat pump commissioning specialists.

Common Problems With Developer-Installed Heat Pumps

Reading developer installed heat pump reviews UK-wide, a pattern emerges. The hardware itself — typically units from Daikin, Mitsubishi, Samsung, or Vaillant — is usually fine. The problems cluster around installation quality, system settings, and the handover process.

Flow temperature misconfiguration

This is the single most common new build heat pump problem. Heat pumps should run at flow temperatures of 35–45°C for underfloor heating to achieve high efficiency. Many systems are commissioned with flow temperatures of 50–55°C — closer to a gas boiler setting — because it's quicker to set up and reduces the risk of residents complaining about insufficient warmth. It also quietly doubles running costs and destroys the COP you were sold on.

Inadequate resident handover

A heat pump is not a boiler. Residents who've never used one before need a proper handover — ideally 30–45 minutes with someone who can explain why leaving it on at a lower, constant temperature is more efficient than turning it up and down. Most developers hand over a manual and a 20-minute slot with a site manager who is simultaneously dealing with four other completions. The result is residents who override the system settings, run it inefficiently, and then complain that heat pumps don't work.

Undersized hot water cylinders

Heat pump hot water recovery is slower than a gas combi. A 150-litre cylinder is borderline for a family of four; 200–250 litres is more appropriate. Some new build specifications cut costs with smaller cylinders, leading to the very real experience of running out of hot water during morning routines — not a failure of heat pump technology, but a failure of system design.

Inadequate weather compensation setup

Modern heat pumps use weather compensation curves to automatically adjust flow temperature based on outside air temperature. When this is set up correctly, the system is both more efficient and more comfortable. It's frequently left unconfigured or misconfigured at handover.

Heat Pump Warranty in New Builds: Developer Responsibility and What's Actually Covered

Heat pump warranty in new build developments involves two overlapping layers that buyers often confuse. The manufacturer warranty — typically 5 years on parts, sometimes extendable to 10 years with registration — covers defects in the unit itself. The developer's structural warranty (usually NHBC Buildmark or similar) covers defects in installation and building fabric for up to 10 years.

The gap between these two warranties is where disputes happen. If the heat pump runs expensively because the system was poorly commissioned, that's arguably an installation defect — but proving it requires an independent assessment, and developers resist claims aggressively. If the unit fails mechanically within the manufacturer warranty period, that's more straightforward.

Buyers should, before signing, ask specifically: who commissions the heat pump? Is it the manufacturer's own team, an MCS-certified installer, or a general trades contractor? MCS certification — the Microgeneration Certification Scheme — matters here because it sets installation and commissioning standards and provides a formal complaints route if things go wrong. A developer who can confirm MCS-certified commissioning is demonstrating a baseline of quality assurance. One who can't, or who isn't sure, is a yellow flag.

The BUS Grant Situation in New Builds (And Why It Mostly Doesn't Apply to You)

The Boiler Upgrade Scheme offers £7,500 towards air source heat pump installation — but it applies to existing properties, not new builds. Developers cannot claim BUS grant funding to offset the cost of heat pumps in new construction. You, as a new build buyer, are paying for a heat pump that's been factored into the property price rather than subsidised at point of installation.

This is worth understanding because it affects the comparison with retrofit. A homeowner switching from a gas boiler to a heat pump in an existing property can access the Boiler Upgrade Scheme's £7,500 contribution, making the economics considerably more attractive. New build buyers are already receiving a notionally efficient system — they just need to ensure it's actually delivering on that promise. If you're comparing your options or considering a heat pump for an existing property alongside a new build purchase, get quotes from MCS-certified installers to understand the full picture.

Questions to Ask Before Exchanging Contracts

The honest answer is that most buyers don't ask nearly enough technical questions before exchanging on a new build with a heat pump — and developers, understandably, don't volunteer information that complicates the sale. Here's what's actually worth asking:

• What make and model is the heat pump, and what is its seasonal coefficient of performance (SCOP) for your climate zone?
• What flow temperature is the system commissioned at, and will it be set up with weather compensation?
• What size is the hot water cylinder, and has it been sized for the maximum occupancy of the property?
• Who is commissioning the heat pump — are they MCS certified?
• What does the manufacturer warranty cover, and who do you contact if there's a problem in year 3?
• Will there be a resident induction session covering heat pump operation?
• Is there monitoring — either via the manufacturer's app or a separate system — so you can track efficiency over time?

A developer who answers these questions confidently, with specifics, is one who's thought about the heating system properly. Vague reassurances that "it's all been taken care of" should make you cautious.

If you want to understand how different heat pump models compare in new build contexts, the air source heat pump comparison tool breaks down real-world performance data across the main UK brands.

What the 2026 Policy Landscape Means for New Build Buyers Going Forward

With the Future Homes Standard now the framework for all new residential development, heat pumps are not an optional extra — they're structural. This has two important implications for buyers. First, resale value: a property that genuinely achieves its EPC A rating through a well-functioning heat pump system is increasingly what lenders, insurers, and future buyers will expect. Second, the market is maturing fast. Volume housebuilders who treated heat pumps as an inconvenient compliance box to tick two years ago are, under market and regulatory pressure, investing more seriously in installer training and commissioning quality. The experience of buyers in 2025–2026 has been, on average, better than those who bought in 2022–2023 when heat pump installations scaled rapidly without equivalent skills development.

The heatwaves affecting Britain this July — which are driving renewed public and political attention to building performance — also highlight something heat pumps in new builds offer that gas boilers categorically do not: the option to run the same refrigerant cycle in reverse for cooling. Not all new build heat pump installations enable this mode from day one, but the capability is there. As summers become more disruptive, that latent cooling function is likely to become a selling point rather than a footnote.

FAQ

Can I negotiate a better heat pump specification when buying off-plan?

Sometimes, particularly with smaller developers or on plots where you're purchasing early. Larger volume housebuilders tend to standardise specifications across a development, but it's worth asking specifically about cylinder size, model choice, and whether weather compensation can be pre-configured. Upgrades are more achievable before construction than after.

Who is responsible if the developer-installed heat pump underperforms against its EPC rating?

This is legally complex. The EPC rating reflects modelled performance, not a guaranteed bill figure, so underperformance alone doesn't constitute a clear breach. However, if poor commissioning is demonstrably causing high running costs, a claim under the NHBC warranty or against the developer under the Consumer Rights Act 2015 is potentially viable — particularly if you can show the system was not installed to manufacturer specifications. Independent assessment is usually required to build that case.

Is a ground source heat pump worth requesting in a new build instead of air source?

On developments with sufficient land area, ground source heat pumps offer higher efficiency (SCOP 4.0–5.0 vs 2.5–3.8 for air source) and quieter operation. The installation cost is higher — roughly £15,000–£25,000 vs £8,000–£14,000 for air source — which developers generally absorb only on premium plots. If you're buying a larger property and the developer offers a ground source option, the long-term running cost saving is meaningful over a 15–20 year horizon.

Will the heat pump affect my mortgage or insurance on a new build?

Most mainstream UK lenders now treat EPC A-rated new builds with heat pumps as standard lending propositions. Some green mortgage products — offered by NatWest, Barclays, Halifax, and others — offer preferential rates for EPC A and B properties, which can translate into meaningful savings over a 2–5 year fixed term. Home insurance is broadly unaffected, though it's worth confirming your insurer understands the system type so any mechanical breakdown cover is correctly specified.

Ready to Understand Your Heat Pump Options?

Whether you're buying a new build and want to verify the heat pump specification you've been quoted, or you're considering alternatives, getting independent installer input makes a real difference. The comparison between what developers specify and what a properly designed system looks like is often instructive.

Compare quotes from MCS-certified heat pump installers — it takes a few minutes, and the information will help you ask better questions before you sign anything.