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Grant Aerona 290 heat pump: what a designer checks before signing one off
The Aerona 290 launched in September 2024 and the range was completed in early 2025, so this is not news — it is a mature product you are likely to find on a quote. Which calls for a different write-up: the checks we run when one turns up in a proposal, and where the published data stops being useful.
- 7 min read
- Published 19 August 2026
AT A GLANCE
THE AERONA 290 AT A GLANCE Grant’s fifth-generation air source range, using R290 propane, launched September 2024 with the 4, 6.5 and 9 kW and completed in early 2025 with the 12 and 15.5 kW. Five models — HPR2904, HPR29065, HPR2909, HPR29012, HPR290155 — all 230 V single phase 50 Hz, 1″ BSP flow and return, charges 0.61 to 1.65 kg. SCOP runs 5.00 to 5.08 at 35 °C and 3.33 to 3.74 at 55 °C (BS EN 14825:2022, average climate); ErP A+++ at 35 °C, A++ at 55 °C throughout. Flow reaches 75 °C for space heating and 70 °C for DHW; the envelope is −25 °C to +35 °C air for heating, −25 °C to +43 °C for DHW. Sound power 48 to 54 dB(A), all five Quiet Mark accredited. DC twin rotary compressor, electronic expansion valve, PWM circulating pump, refrigerant leak sensor. QR2 cylinders from 150 to 300 litres and the Aerona Smart Controller complete the ecosystem. Seven-year guarantee — but only via a Grant G1 accredited installer.
First, the name
The official name is the Aerona 290. You will see it written “Aerona R290” almost everywhere, including by us in conversation, because R290 is the refrigerant — propane. Both find the same machine, so little turns on it; but when cross-referencing datasheets or hunting a certificate number, search the model code. It is Grant’s fifth-generation range, after fifteen years supplying UK heat pumps — which matters less for reliability than people assume, and more for parts and installer familiarity.
The hardware, briefly
A DC twin rotary compressor, an electronic expansion valve and an integrated PWM circulating pump. The pump is the quiet win: modulating circulation holds a narrower delta-T at part load instead of blasting a fixed flow rate through a system that does not want it. A refrigerant leak sensor comes as standard — exactly what you want on a propane machine, and increasingly what insurers want too.
The flow temperature figure almost everyone gets wrong
The Aerona 290 will produce up to 75 °C flow for space heating and 70 °C for DHW, across stated operating ranges of 25–75 °C and 20–70 °C. It is not a 55 °C machine. 55 °C is the rating condition — where the SCOP and ErP figures are declared — and it is repeatedly misreported as a ceiling.
Now the part that matters more. Grant publishes no performance data above 55 °C, and there is no internal electric booster; the only heating element is a base-tray anti-freeze heater. So 75 °C is a capability, not a design target. You cannot size to it, because you have nothing to size with: no capacity table, no COP, no indication of how far into the ambient range that flow stays available — and high flow gets harder as the air gets colder, precisely when you would want it.
Treat 75 °C as headroom and design the emitters properly instead. Our radiator output calculator will tell you in a minute whether your rads carry the load at 45 or 50 °C, and whether your radiators can work with a heat pump has an arithmetic answer, not an opinion.
Efficiency is not uniform across the range
This is the most useful thing in the datasheet, and the thing quotes never mention.
Seasonal efficiency, BS EN 14825:2022, average climate:
| Model | SCOP @ 35 °C | SCOP @ 55 °C |
|---|---|---|
| 4 kW | 5.00 | 3.66 |
| 6.5 kW | 5.08 | 3.62 |
| 9 kW | 4.74 | 3.69 |
| 12 kW | 4.74 | 3.74 |
| 15.5 kW | 4.56 | 3.33 |
The 6.5 kW is the star at 35 °C, on 5.08. The 15.5 kW is the weakest at both conditions — 4.56 and 3.33 — and the gap at 55 °C is not trivial. The ordering also flips: at 55 °C the 12 kW leads on 3.74 while the 6.5 kW drops to 3.62. A badge on a range does not buy you a number. Each model earns its own.
The published capacity and COP figures are BS EN 14511 at A7/W35, A7/W55 and A-5/W55 — instantaneous test points, not seasonal. If a quote hands you one glossy COP, ask which of the three produced it. That is one reason quotes for the same house differ so wildly.
Sound, siting and the operating envelope
Two corrections.
The envelope. Space heating operates from −25 °C to +35 °C air temperature; DHW from −25 °C to +43 °C. Grant’s own R290 page notes the unit is “rated at −5 °C air temperature and 55 °C water flow”, and that line gets quoted as though −5 °C were a cut-off. It is a rating point. The machine runs a good deal colder than that.
The sound data, which is not monotonic. Sound power to BS EN 12102-1 runs 48 / 52 / 54 / 52 / 53 dB(A) for the 4 / 6.5 / 9 / 12 / 15.5 kW. The 9 kW is the loudest in the range at 54 dB(A) — not the 15.5 kW, as everyone reasonably assumes. If you are squeezing a 9 kW onto a tight plot because it was “the smaller one”, check that again.
For sound pressure, always state the directivity factor. At 1 m, Q=1 gives 37.0 / 40.7 / 42.6 / 41.0 / 41.9 dB(A); Q=2 — a reflecting surface behind the unit — gives 40 / 44 / 46 / 44 / 45 dB(A), falling to 31 / 34 / 36 / 34 / 35 dB(A) at 3 m. Grant’s brochure headline of “40 dB to 46 dB at 1 metre” is the Q=2 set. MCS 020 planning work lives or dies on the right Q for the actual siting, so a figure quoted without one is worse than no figure. All five are Quiet Mark accredited.
Warranty, MCS and what is actually known about reliability
The guarantee is seven years — when installed by a Grant G1 accredited installer, subject to terms and completed training. That is a warranty on the installer as much as on the box. Ask in writing whether the company quoting you holds G1 accreditation; the difference between seven years and the statutory minimum is decided before anyone lifts a spanner.
On MCS: Grant states on its consumer pages that the range is “MCS approved so eligible for Government grants including the Boiler Upgrade Scheme”, and describes it as MCS accredited professionally, with Connect and Notify approval. We report that as Grant’s claim — we could not verify certificate numbers in the MCS Product Directory. Before relying on it for funding, look up your exact model code there yourself.
Known issues: none documented. We found no credible criticism across trade press, Renewable Heating Hub, OpenEnergyMonitor or BuildHub; one forum thread concerned a 17 kW Aerona, not part of the 290 range. Read that carefully — absence of documented complaints is not proof of quality. The range has been in volume installation for under two years, and field data lags. The one independent professional account we found is Ricky Prescott’s review for Installer Online: a 6.5 kW at 45 °C flow, −2.4 °C design temperature, 180 litre Grant QR single-coil cylinder. Positive, the only issue a site-specific loft constraint. One house, honestly reported, and worth that much.
The surrounding ecosystem is Grant’s QR2 cylinders, 150 to 300 litres, including pre-plumbed QR2 Smart indirect models, plus the Aerona Smart Controller — 4.5″ touchscreen, WiFi hub, remote monitoring. That last item earns its keep: it is the difference between a system you can diagnose and one you can only guess at.
AERONA 290 — PUBLISHED SPECIFICATION, ALL FIVE MODELS
| Model code | Output | R290 charge | Sound power | Sound pressure @ 1 m (Q=1) | Weight (empty) | H × W × D (mm) |
|---|---|---|---|---|---|---|
| HPR2904 | 4 kW | 0.61 kg | 48 dB(A) | 37.0 dB(A) | 99 kg | 803 × 1155 × 422 |
| HPR29065 | 6.5 kW | 0.83 kg | 52 dB(A) | 40.7 dB(A) | 115 kg | 854 × 1223 × 461 |
| HPR2909 | 9 kW | 1.00 kg | 54 dB(A) | 42.6 dB(A) | 131 kg | 854 × 1223 × 461 |
| HPR29012 | 12 kW | 1.20 kg | 52 dB(A) | 41.0 dB(A) | 153 kg | 1365 × 1155 × 425 |
| HPR290155 | 15.5 kW | 1.65 kg | 53 dB(A) | 41.9 dB(A) | 180 kg | 1365 × 1155 × 425 |
All 230 V single phase, 50 Hz, 1″ BSP flow and return. Full weights 102–184 kg. Sound power to BS EN 12102-1.
DESIGNER'S INSIGHT
“The 75 °C headline is the one I unpick most often. It is real — the machine will do it — but Grant publishes nothing above 55 °C and there is no booster inside, so you are being offered a capability with no data attached, and I cannot design to a number I cannot look up. What I can design to is that SCOP table, and it rewards what every table rewards: get the flow temperature down. Check sound power against the model too, not the range — the 9 kW being the loudest here is the sort of detail that decides whether a unit clears MCS 020 on a terrace boundary.”
Phil
Founder & Lead Designer, Heat Loss Hub
A designer's honest take
Heat Loss Hub is independent. We hold no Grant account, take no manufacturer incentives, do not install and earn no commission — so read this as engineering commentary rather than endorsement.
On the data, the Aerona 290 is a competent, well-specified range. R290 with a leak sensor as standard, a PWM pump, an EEV and a twin rotary compressor is a modern package, and 5.08 at 35 °C on the 6.5 kW is a genuinely strong SCOP. Against a Vaillant or Samsung unit it will win some houses and lose others, on your emitters and design conditions rather than the badge.
Two caveats stand. The efficiency spread is wide enough to matter, so check the model quoted is the one earning the figures you were shown. And treat the seven-year guarantee as conditional until you have confirmed your installer’s G1 status.
Which is where these pieces land: none of it can be judged without knowing your house. Work out what size heat pump you need from a room-by-room heat loss calculation, establish the flow temperature your emitters can live with, and then read the tables. When a Grant unit wins a place on one of our drawings it will be because its numbers at your conditions beat the alternatives — and when they do not, something else goes on instead. If you would like that done properly, start your design journey.
SOURCES
- Grant UK — Aerona 290 professional range page
- Grant UK — Introducing the Aerona 290
- Grant UK — The Aerona 290, Grant's fifth generation heat pump, is here (news release, 13 September 2024)
- Grant UK — Aerona 290 datasheet (July 2026)
- Grant UK — Aerona 290 installation manual, DOC 0204 Rev 1.8
- Installer Online — Grant Aerona 290 heat pump: a professional review (Ricky Prescott)
- MCS Product Directory
CONTENTS
BRAND-NEUTRAL, ALWAYS
We specify from performance data at your design conditions — this unit when it wins, something else when it does not.
NEW PRODUCTS, TIMELESS METHOD
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