New Build EPC A Rating and Heat Pumps: What UK Buyers Actually Need to Know in 2026

New Build EPC A Rating and Heat Pumps: What UK Buyers Actually Need to Know in 2026

Last updated: 10 May 2026

Around £2,000 per year. That is what some new-build buyers are paying to run a developer-installed heat pump they did not fully understand before they signed contracts — and in some cases, it is significantly more than their gas-heating neighbours pay. The EPC A rating on the brochure looked excellent. The running costs told a different story. This article is for anyone buying or already living in a new-build with a heat pump, or any developer trying to understand what getting this right actually looks like in practice.

Why New Builds Are Rated EPC A — and What Heat Pumps Have to Do With It

An EPC A rating means a property scores 92 or above on the Standard Assessment Procedure (SAP) energy efficiency scale. For new builds, achieving this without a heat pump has become increasingly difficult. Modern insulation standards, triple-glazed windows, and mechanical ventilation with heat recovery (MVHR) all contribute, but the heating system itself carries enormous weight in the SAP calculation. Heat pumps generate their score advantage because they move heat rather than burn fuel — a well-sized air source heat pump running at a Coefficient of Performance (COP) of 3.0 produces three units of heat for every one unit of electricity consumed.

The result: developers increasingly specify heat pumps not because they are the most straightforward heating technology to manage, but because they are the most reliable route to the ratings buyers expect and planning authorities increasingly demand.

The Future Homes Standard Is Coming — Here Is What That Means

The Future Homes Standard heat pump requirement UK 2026 has been one of the most discussed policy topics in the housebuilding sector for the past three years. Under the standard, new homes built from 2025 onwards are required to produce 75–80% less carbon than a home built under 2013 regulations. In practical terms, this almost certainly means no gas boiler connections for new builds. Heat pumps, district heating networks, and hybrid systems will be the primary alternatives.

The final implementation details were confirmed in early 2025, but some large developers had already begun transitioning their standard specifications from 2023 onwards, partly in anticipation of the regulation and partly because a growing proportion of buyers were specifically requesting low-carbon heating. For buyers completing on new properties in 2026, there is a meaningful chance your home already falls under the Future Homes Standard's predecessor regulations — meaning the heat pump in your plant cupboard is not optional equipment; it is the designed heating system.

Developer-Installed Heat Pumps: What Goes Wrong and Why

New build heat pump problems UK buyers report cluster around a small number of recurring themes, and most of them trace back to commissioning rather than the technology itself.

Oversized or undersized units

A heat pump must be sized to match the heat loss of the property — not the property's square footage, and not the developer's preference for a single SKU across an entire development. Oversized units short-cycle: they reach temperature quickly, switch off, and then restart repeatedly, wearing components faster and reducing efficiency. Undersized units struggle on cold days and leave residents increasing their thermostat, burning more electricity without achieving comfortable temperatures. In a new-build context where the developer is managing margins across hundreds of units, getting individual sizing right is genuinely difficult — and too often, it does not happen.

Flow temperature set incorrectly

Heat pumps perform most efficiently at lower flow temperatures — ideally 35–45°C for underfloor heating, which most new builds use. Many developer-installed systems arrive with flow temperatures set at 55°C or higher, a legacy of gas boiler settings. Nobody changes them at handover. The buyer moves in, the system runs at sub-optimal efficiency, and bills are higher than they should be. This is one of the most common and most fixable problems — but only if the buyer knows to check.

Tariff mismatch

Heat pumps running on a standard electricity tariff at 24–26p/kWh are at a significant cost disadvantage compared with gas at 6–7p/kWh, even accounting for the COP advantage. Time-of-use tariffs such as Octopus Agile or Economy 7 can reduce the effective rate to 10–15p/kWh during off-peak hours. The developer-installed heat pump review UK experience almost universally highlights that buyers were never told which tariff to get.

New Build vs Retrofit: The Fundamental Difference That Changes Everything

The heat pump new build vs retrofit UK difference is more significant than most buyers appreciate. In a retrofit context, the heat pump is being fitted to an existing building with existing radiators, existing flow temperatures, and existing heat loss characteristics. The installer must adapt the system to the building. In a new build, the building is designed around the heating system — or at least, it should be. Underfloor heating throughout, high insulation values, and controlled ventilation all make the heat pump's job substantially easier. The technology that struggles in a Victorian terrace with single-glazed sash windows and 1960s radiators becomes considerably more capable when it is paired with a well-built 2024 home.

This is why the EPC A rating is achievable — and why, when problems do emerge, they are almost always the result of poor commissioning or configuration rather than fundamental incompatibility. The system should work. Getting it to work as well as it should requires attention to detail that generic developer processes do not always provide.

Understanding Your Warranty — Developer Responsibility and MCS Certification

Heat pump warranty new build UK developer responsibility is an area of genuine confusion. Most heat pump manufacturers offer 5–7 year warranties on the unit itself, with some offering up to 10 years if the system is serviced annually by an approved engineer. The developer's responsibility typically ends at practical completion, but there are obligations under the Consumer Code for Housebuilders and the NHBC Buildmark warranty that cover defects in workmanship — which would include a heat pump that was incorrectly commissioned.

MCS (Microgeneration Certification Scheme) certification matters here specifically because it provides a regulated installation standard against which complaints can be assessed. An MCS-certified installer must follow a defined process including heat loss calculations, system design documentation, and commissioning records. If your developer used an MCS-certified installer and you have a copy of the commissioning certificate, you have documentation. If they did not, your position is weaker. Always ask for the MCS commissioning certificate at handover.

Annual servicing protects your warranty and efficiency — it also gives you an independent engineer's view of whether the system was set up correctly in the first place.

Costs, Running Expenses, and Where Grants Fit In

One point worth making clearly: the £7,500 Boiler Upgrade Scheme grant — available through the Boiler Upgrade Scheme — does not typically apply to developer-installed heat pumps in new builds, because it is designed for self-commissioned replacements of fossil fuel systems. If you are buying a new build, you will not be eligible for the BUS grant on that property. However, if you later need to replace the unit and are paying for it yourself, eligibility may apply at that point. It is a distinction that catches buyers off guard.

What to Check Before You Sign — and After You Move In

The honest answer is that most new-build buyers do not know enough about their heat pump to ask the right questions before exchange, and developers do not volunteer the information. Here is what actually matters.

Before exchange, ask the developer: which manufacturer and model is being installed; whether the installer is MCS-certified; what the designed flow temperature and heat loss calculation shows; and whether the system qualifies for the manufacturer's full warranty period. Request the commissioning documentation in writing as a condition of handover.

After moving in, within the first month: check the flow temperature setting on the controller (it should be 35–45°C for underfloor heating systems); switch to a time-of-use electricity tariff if you have not already; book a smart meter installation if one was not fitted; and locate the MCS certificate and manufacturer warranty documentation.

If anything feels wrong — persistent cold spots, the system running almost continuously, bills that seem inconsistent with neighbours in similar-sized homes — get an independent assessment from an MCS-certified engineer. Problems caught at six months are far easier to resolve under warranty than problems discovered at three years. For independent comparisons of air source heat pump models suitable for new builds, including efficiency ratings and real-world COP data, it is worth reviewing what is available before deciding whether your developer-specified unit is the right long-term choice.

Frequently Asked Questions

Does the EPC A rating on my new build mean the heat pump is guaranteed to be efficient?

Not exactly. The EPC A rating reflects the theoretical performance of the heating system under standard assessment conditions, not the real-world operating efficiency of the specific unit installed in your home. A heat pump set to the wrong flow temperature or running on an expensive electricity tariff will underperform relative to the EPC's assumptions. The rating is a useful benchmark but not a guarantee of low bills.

Who is responsible if my developer-installed heat pump develops a fault in the first two years?

Typically, the manufacturer's warranty covers component failures, and the developer has obligations under the NHBC Buildmark warranty for defects in workmanship and design. If the fault relates to incorrect commissioning — wrong flow temperatures, incorrect system design — this could fall under the developer's responsibility. The MCS commissioning certificate is the key document that establishes what the system was designed to do and how it was set up.

Will the Future Homes Standard affect homes being built now in 2026?

Yes. The Future Homes Standard's requirements were introduced progressively, and homes completing in 2026 are subject to regulations that effectively require very low-carbon heating. The majority of new builds completing now will have heat pumps as their primary heating system, with gas boiler connections no longer permitted in new residential properties under current planning policy.

Can I replace a poorly performing developer heat pump with a different model myself?

Yes, though doing so during the developer warranty period may complicate any warranty claims. If you do replace the unit, using an MCS-certified installer is essential — it is also a requirement to access the £7,500 BUS grant if your circumstances make you eligible. An independent installer can also redesign the system properly, including recalculating heat loss for your specific property and setting correct flow temperatures from the outset.

Getting This Right From the Start

A well-specified, correctly commissioned heat pump in a new EPC A-rated build is genuinely capable of heating your home at a lower carbon footprint and, with the right tariff, at competitive running costs. The technology is sound. The problems are almost always in the process — developer corners cut on commissioning, buyers not briefed at handover, tariff choices left to chance. Understanding the difference between a good installation and a mediocre one is the first step toward either fixing what you have or making a better decision going forward.

If you want to compare what a properly specified system should look like — or get quotes from MCS-certified installers who can assess an existing installation — get quotes through our installer network and find out what your heat pump should actually be doing for your home.