Grant Aerona3 Review: Irish-Made Heat Pump Taking On the Big Brands

Grant Engineering may not have the name recognition of Vaillant or Mitsubishi, but the Irish manufacturer has been producing heating systems for over 40 years and their Aerona3 air source heat pump range is turning heads across the UK. This grant aerona heat pump review covers both the established R32 Aerona3 and the newer Aerona 290 R290 model, examining why installers consistently rate Grant as one of the best heat pump brands available and whether it deserves a place on your shortlist.

Is the Grant Aerona3 a Good Heat Pump?

Yes, the Grant Aerona3 is a strong choice for UK homeowners, particularly in damp, mild climates. Manufactured in Ireland, it is specifically designed for Atlantic weather conditions similar to much of western Britain. The Aerona3 range covers 6–17 kW output, achieves a seasonal COP of 3.2–3.8 in real-world UK conditions, and costs £8,000–£12,000 installed before the £7,500 BUS grant. It comes with a five-year warranty extendable to seven years with annual servicing.

The Aerona3’s standout feature is its quiet operation — the 10 kW model runs at just 40 dB at one metre, making it one of the quietest heat pumps available for semi-detached and terraced properties where neighbour noise is a concern. Grant’s UK and Ireland service network is well-established, and spare parts are readily available. It uses R32 refrigerant rather than the newer R290, which is the main trade-off against competitors like the Vaillant Arotherm Plus.

Grant Aerona3 Range: R32 and R290 Models Explained

Grant currently offers two heat pump lines. The original Aerona3 R32 has been available for several years and is available in 6kW, 10kW, 13kW, and 17kW capacities. The newer Aerona 290 uses R290 (propane) refrigerant and is available in 6kW, 10kW, and 14kW capacities.

Both ranges are monobloc designs manufactured at Grant’s factory in County Offaly, Ireland. The company’s proximity to the UK market means shorter supply chains, better parts availability, and a responsive technical support team that UK installers regularly praise.

Exceptional Efficiency: SCOP of 5.41 Explained

The headline figure for the Aerona 290 is its ErP COP rating of 5.41 at A7/W35, which is one of the highest laboratory efficiency figures of any air source heat pump available in the UK. This means that under test conditions at 7C outdoor temperature and 35C flow temperature, the unit produces 5.41kWh of heat for every 1kWh of electricity consumed.

In real UK homes, expect seasonal COP figures between 3.3 and 4.5 depending on installation quality, flow temperatures, and property insulation. The high laboratory figure does translate into a genuine real-world efficiency advantage over competitors, with the R290 refrigerant’s superior thermodynamic properties contributing a 5-12% efficiency gain over equivalent R32 units in typical UK conditions.

Installers who have monitored Grant Aerona 290 installations report that achieving SCOP figures above 4.0 is straightforward in well-insulated homes with underfloor heating or correctly sized radiators. This places the Grant among the top two or three most efficient air source heat pumps in the UK market, alongside the Vaillant Arotherm Plus and Samsung EHS Gen 7.

Quiet Mark Accreditation and Noise Performance

Both the Aerona3 R32 and Aerona 290 hold Quiet Mark accreditation from the Noise Abatement Society, an independent certification that recognises products meeting strict noise standards. This is a meaningful distinction, as only a handful of heat pumps in the UK market have achieved this certification.

The Aerona 290 produces 46-54dB at 1 metre in standard operation, translating to approximately 34-42dB at 3 metres. This comfortably meets the 42dB permitted development limit at property boundaries for most installations, though careful positioning is still advisable for terraced homes or units placed close to shared boundaries.

Grant achieves its quiet operation through a combination of inverter-driven compressor technology, aerodynamically optimised fan blades, and sound-dampening panels within the unit casing. A dedicated quiet mode further reduces noise output for overnight operation.

Grant Aerona3 Installed Costs in the UK

The Grant Aerona3 sits in the mid-range for installed costs, typically coming in at £9,000-£12,000 fully installed for a standard 3-4 bedroom UK home. This positions it between the Samsung EHS Gen 7 (which is cheaper) and the Vaillant Arotherm Plus (which costs more).

After the £7,500 Boiler Upgrade Scheme grant, net costs drop to approximately £1,500-£4,500. The newer Aerona 290 models command a slight premium over the R32 versions, but the efficiency gains typically recover this difference within 3-5 years through lower running costs.

Grant’s supply-only pricing is competitive, with outdoor units typically costing £3,000-£5,500 depending on capacity. The company also manufactures its own hot water cylinders specifically designed for heat pump use, which simplifies the specification process and ensures compatibility. Get a free quote to see the installed price for your specific property.

The G1 Installer Network

Grant operates the G1 installer network, a training and accreditation programme for heating engineers who specialise in Grant products. G1 installers receive factory training, priority technical support, and access to extended warranty programmes. Using a G1 installer is required to activate the full 7-year warranty.

The G1 network is smaller than Mitsubishi’s or Vaillant’s installer bases, with approximately 1,500 accredited installers across the UK and Ireland. Coverage is strongest in Ireland (where Grant is the dominant heating brand), Northern England, Scotland, and rural areas where Grant’s oil boiler heritage has built strong relationships with heating engineers.

In parts of southern England and major cities, finding a G1 installer may require more effort. However, the network is expanding as Grant’s UK market share grows, and the company’s technical support team is known for being exceptionally responsive compared to larger multinational brands.

Grant vs Vaillant, Samsung and Mitsubishi

Choosing between the top heat pump brands requires weighing up specific priorities. Here is how the Grant Aerona 290 compares to its closest rivals on the metrics that matter most to UK homeowners.

The Grant’s strengths lie in its combination of high efficiency, competitive pricing, and strong warranty. It matches the Vaillant on refrigerant choice and nearly matches it on efficiency, while costing significantly less. The Samsung remains the cheapest option but has a lower maximum flow temperature of 65C.

Who Should Choose the Grant Aerona3?

The Grant Aerona3 is an excellent choice for homeowners who want premium R290 efficiency without the premium price tag of the Vaillant. It is particularly well-suited to:

• Rural properties where Grant’s installer network is often stronger than city-focused brands
• Homes currently using oil heating, where Grant’s oil boiler heritage means many existing installers already know the brand
• Properties needing up to 70C flow temperature for existing radiators without expensive upgrades
• Homeowners who value responsive UK-based technical support over multinational call centres

Before installation, ensure your home is as energy-efficient as possible. Upgrading loft and cavity wall insulation reduces heat demand and allows the heat pump to run at lower, more efficient flow temperatures. Pairing the Aerona with solar panels can offset a significant portion of the electricity consumption, particularly during the shoulder months of spring and autumn.

For homes still running oil boilers, the switch to a Grant heat pump is particularly compelling. Oil heating costs approximately 8-10p per kWh of heat at current prices, while the Aerona 290 at an SCOP of 4.0 delivers heat for approximately 6.1p per kWh. Combined with eliminating the need for oil deliveries and storage tanks, the transition offers both financial and practical benefits.

Frequently Asked Questions

Is the Grant Aerona3 as reliable as Vaillant or Mitsubishi?

Early reliability data for the Aerona3 is very positive. Grant has a strong reputation for build quality across their product range, and the 7-year warranty reflects confidence in durability. While it lacks the 15-year UK track record of the Mitsubishi Ecodan, installer feedback consistently rates Grant’s quality and after-sales support highly.

Can I get the BUS grant with a Grant heat pump?

Yes. All Grant Aerona3 R32 and Aerona 290 models are MCS-certified and eligible for the £7,500 Boiler Upgrade Scheme grant. The grant is applied at the point of installation through your MCS-certified G1 installer. Request a free quote to see your net cost.

Should I choose the Aerona3 R32 or the Aerona 290 R290?

If budget allows, the Aerona 290 (R290) is the better long-term choice. It offers higher efficiency, a more environmentally friendly refrigerant that will not face future regulatory phase-downs, and a higher maximum flow temperature of 70C vs 65C. The R32 model remains a solid option if the R290 version is unavailable in your required capacity or if the price difference is a concern.

How does Grant’s after-sales support compare to bigger brands?

Grant consistently receives praise from UK installers for responsive technical support, with phone wait times typically shorter than Vaillant, Daikin, or Mitsubishi. The company’s smaller size means enquiries are handled by experienced engineers rather than general call centre staff. Parts availability is good, with most components available for next-day delivery within the UK.

What size Grant Aerona do I need for my home?

Sizing depends on your home’s heat loss, which must be calculated through a proper survey. As a rough guide, a well-insulated 3-bedroom semi-detached house typically needs 6-8kW, while a larger 4-5 bedroom detached property may need 10-14kW. Oversizing a heat pump reduces efficiency, so accurate sizing is essential.