Best Air Source Heat Pump UK 2026: Efficiency and Value Ranked

The UK heat pump market has matured sharply. Five years ago, only specialists knew what a SCOP was; today, manufacturers publish certified seasonal efficiency figures, the Boiler Upgrade Scheme (BUS) puts £7,500 in your pocket before installation begins, and a genuine shortlist of excellent models has emerged. This guide focuses on one question: which model should you actually buy? If you want a deeper explanation of what SCOP and COP mean, read our heat pump efficiency explainer first.

What to look for in a UK air source heat pump

SCOP at your flow temperature is the single most important number. Most UK radiator systems run at 55–65 °C; well-insulated homes with underfloor heating can drop to 35–45 °C, where every model scores better. Look for an ErP SCOP above 3.5 at your actual flow temperature — not just the manufacturer's best-case 35 °C figure.

Noise output matters if neighbours are close. Planning guidance in England requires sound levels below 42 dB(A) at a neighbour's window (about 1 metre away) for permitted development. Premium models sit well beneath this threshold.

Sizing is determined by a Heat Loss Calculation (HLC) under MCS standard MIS 3005 — your MCS-certified installer must produce one before specifying a unit. As a rough guide, a 3-bedroom semi-detached typically needs a 5–8 kW unit; a larger detached four-bedroom may need 10–12 kW.

Refrigerant is shifting fast. R290 (propane, GWP 3) is replacing R32 (GWP 675) across the premium range. R290 units reach higher flow temperatures more efficiently and have a lower environmental impact. Where both options exist in a range, the R290 variant is usually the better long-term choice.

MCS certification is mandatory for BUS grant eligibility. The product and the installer must both appear on the MCS register. Never accept a quote that does not include an MCS certificate.

The Boiler Upgrade Scheme: your starting point

The BUS provides a £7,500 upfront grant toward the installation of an MCS-certified air source heat pump in England and Wales (Scotland has its own Heat Pump Support Scheme). Your installer applies on your behalf; you never handle the money. Eligibility requires replacing a fossil-fuel heating system and holding an EPC with no outstanding loft or cavity wall insulation recommendations. Total installed costs before the grant typically run from £9,000 to £15,000 depending on property size, system complexity, and brand chosen — bringing real out-of-pocket costs down to £2,000–£7,500 for most households.

Top 5 air source heat pumps for UK homes in 2026

1. Vaillant aroTHERM+ — Best overall efficiency

SCOP up to 5.03 at 35 °C (A+++ ErP), noise from 44 dB(A), R290 refrigerant, 5-year warranty. The aroTHERM+ consistently tops independent efficiency comparisons. Its R290 refrigerant allows flow temperatures up to 75 °C, making it genuinely suitable for retrofit into older homes with existing radiators — without an upgrade. Vaillant's Sound Safe System and Quiet Mark certification on four of the five output variants (3.5 kW to 12 kW) mean noise is rarely a planning concern. The installer network is deep and the multi-zone interface integrates cleanly with Vaillant's own controls. At list price it is not the cheapest unit, but the efficiency edge reduces running costs year on year.

2. Daikin Altherma 3 H HT — Best for older radiator systems

Peak COP up to 5.43, operates to −28 °C, ultra-quiet from 35 dB(A) at 3 m, Quiet Mark accredited. The Altherma 3 High Temperature variant is designed explicitly for retrofit into homes with existing high-temperature emitters. Its operating range — down to minus 28 °C ambient — is the widest in this roundup, giving it a real edge in Scotland and northern England where winter temperatures dip harder. The low-sound mode drops sound pressure to 35 dB(A) at 3 metres, comfortably within permitted development limits even on tightly spaced plots. Daikin's UK distribution is mature and spares availability is strong.

3. Mitsubishi Ecodan — Largest UK installed base

SCOP up to 4.6, 45–62 dB(A) depending on model, manufactured in Livingston, Scotland, 5-year warranty extendable to 7 years. The Ecodan is the most widely installed heat pump brand in the UK, which translates to the largest pool of experienced service engineers and the easiest access to parts. The flagship PUZ-WZ range uses R290 and carries Quiet Mark accreditation. If post-installation support and peace of mind are priorities — particularly outside major cities — the Ecodan's coverage is unmatched. Efficiency is excellent, if a fraction below Vaillant's best-case SCOP.

4. Samsung EHS Gen 7 — Best for ultra-quiet urban installs

SCOP up to 4.9 at 35 °C (A+++), as low as 35 dB(A) on the HT Quiet model, 5 kW to 16 kW range, 7-year warranty with Samsung-certified installer. Samsung's EHS Gen 7 R290 range is engineered specifically for low-noise urban use. The HT Quiet model holds 35 dB(A) — quieter than a typical library reading room — which is particularly valuable for terraced housing. Samsung has also extended its warranty to 7 years through its certified installer programme, which closes a gap that dogged earlier generations. The wide capacity range (5–16 kW) makes it scalable to larger homes without switching platform.

5. Octopus Cosy 6 — Best for Octopus Energy customers

SCOP 3.6 real-world average (fleet data), A++ rated, 8-year product warranty, 5-year labour warranty, all-in supply-and-install pricing. Octopus's own-brand heat pump is not the most efficient unit on this list, but it is the most clearly priced: Octopus publishes fixed all-in installation quotes and handles survey, MCS paperwork, BUS grant application, and commissioning as a bundled service. For customers already on Octopus tariffs — particularly the Cosy Octopus time-of-use tariff, which offers cheap off-peak slots designed around heat pump operation — the end-to-end integration is compelling. The 8-year product warranty is the longest on this list. Real-world fleet SCOP averages around 3.6, slightly below manufacturer certificates, which is honest and transparent.

Quick comparison

The table below summarises the key purchase-decision metrics. All SCOP figures are ErP-rated at 35 °C; real-world seasonal performance at higher flow temperatures will be lower.

What about ground source heat pumps?

Ground source heat pumps (GSHPs) extract heat from the ground rather than the air, giving more stable winter efficiency but at significantly higher installed cost: £18,000–£35,000 before grants, depending on whether horizontal trenches or vertical boreholes are used. The BUS grant applies equally. GSHPs suit properties with large gardens and are worth considering if you have the land and budget — but for the majority of UK semi-detached and terraced homes, an air source unit is the practical starting point. See the keyword nest “ground source heat pump cost UK” for a detailed breakdown when you are ready to compare.

Solar panels and heat pumps: a natural pairing

Running a heat pump on self-generated solar electricity dramatically reduces operating costs. A 5 kW heat pump drawing power from a rooftop solar array can cut electricity bills by an additional 20–40% compared with grid-only operation during spring and summer. Smart tariffs (such as Octopus Flux or Agile) can extend those savings through the shoulder months. To understand what a solar install would cost and how it stacks up financially, our solar panel cost and savings guide covers 2026 prices and payback projections in detail. If you're also weighing how to use surplus solar intelligently, the comparison of solar diverters, batteries, and EV charging is worth reading before you finalise your system design.

Getting a quote

Any heat pump installer you approach must be MCS-certified. Require a Heat Loss Calculation before accepting a specification — an installer who quotes a unit size without one is not following MCS standards. Get at least two quotes; prices vary by £2,000–£4,000 between installers for the same unit in many cases. Your installer will apply for the BUS grant on your behalf; you should not need to contact Ofgem directly.