Vaillant aroTHERM plus

What changed in the second generation

Anthracite finish

The old aroTHERM plus came in white. The new model ships only in anthracite (RAL 7021). For most UK homes with brick, render, or timber cladding, this is a better fit.

Flexible Space Function

The first-generation aroTHERM plus required a 1-metre exclusion zone in all directions. No plug sockets, switches, or openable windows could sit within that radius. The new model has Flexible Space Function built in. When your installer activates it during commissioning, the exclusion zone applies only below the unit, which opens up siting options that were off-limits before.

Two things worth knowing: activating Flexible Space Function causes a small efficiency reduction and a small increase in standby energy use. For most properties it is worth that trade-off to unlock a better siting position. On gardens with no space constraint, leaving it deactivated recovers maximum efficiency.

Sound levels

The old model ran at 51 dB(A) on the 5 kW version and 53 dB(A) on the 7 kW. The new generation runs at 44.1 dB(A) (3.5 kW), 44.3 dB(A) (5.5 kW), and 46.8 dB(A) (7.5 kW) under standard heating conditions. The larger 10.5 kW and 12.5 kW models run at 50.0 dB(A). That drop across the smaller sizes is substantial. For homes where the unit sits close to a bedroom window or a neighbouring property, it changes the calculation.

The unit also has a built-in Sound Safe System with noise reduction modes (40%, 50%, and 60%) that drop output further when quieter operation is needed overnight.

Extended cold-weather range

The heating operating range now reaches -25°C outside temperature, down from -20°C on the previous generation. That improvement matters little for most UK winters, but it adds a margin for hard frosts.

New interface

The front panel now has a semi-touchscreen display alongside the sensoCOMFORT controller. Homeowners will still interact with the system day-to-day through the myVaillant app or the sensoCOMFORT. The new display is primarily relevant during commissioning and servicing.

Up to 7-year guarantee

Register through Vaillant's myREWARDS programme and pair the unit with a Vaillant uniSTOR cylinder and the guarantee extends to 7 years. The standard guarantee applies without that pairing.

What stays the same

R290 refrigerant. Maximum 75°C flow temperature. Weather compensation via sensoCOMFORT. Wall mounting on the smaller models. BUS grant eligibility.

The fundamentals have not moved. A correct heat loss calculation, properly sized radiators or underfloor heating, and well-configured weather compensation still account for the bulk of how efficiently your system runs. Installation quality matters more than the hardware specification.

Size range

The second-generation aroTHERM plus covers the same broad range as the original: 3.5 kW, 5.5 kW, 7.5 kW, 10.5 kW, and 12.5 kW. The three smaller models are single-phase 230V units. The two larger models are available in both 230V single-phase and 400V three-phase versions. The 400V option gives installers more flexibility on larger properties where a three-phase supply is available.

aroTHERM plus vs aroTHERM pro

Vaillant launched the aroTHERM pro in 2026 alongside the first-generation plus. With the second-generation update, the two products share considerably more than before: both use R290, both have Flexible Space Function, and both come in anthracite.

Size range

The plus covers 3.5 kW, 5.5 kW, 7.5 kW, 10.5 kW, and 12.5 kW. The pro covers 5 kW, 7 kW, and 11 kW. If your heat loss comes in below 5 kW, the plus is your only option between the two. Above 12.5 kW, neither covers that territory as a single unit.

Specification

The plus has the upgraded semi-touchscreen interface and reaches COP figures of up to 5.39. It was designed as the premium product in the range. The pro was introduced at a more accessible price point.

Guarantee

The 7-year guarantee path is specific to the plus paired with the uniSTOR cylinder via myREWARDS.

For most homes, both products perform well when installed correctly. The right choice usually follows from the heat loss calculation: size availability narrows the field, then your installer can advise on which fits the system design better.

The aroTHERM plus and hot water

Heat pumps do not heat space and hot water at the same time. A cylinder is not optional. Pairing the aroTHERM plus with the Vaillant uniSTOR also unlocks the 7-year guarantee route. We also regularly install it with the Heat Geek Super Cylinder, which is designed to run hot water cycles at lower flow temperatures. Lower flow temperatures mean higher efficiency. Independently monitored installations with this pairing consistently produce hot water at 400 to 550% efficiency.

Boiler Upgrade Scheme grant

The aroTHERM plus is eligible for the BUS grant. The current grant is £7,500 for gas-heated homes and £9,000 for oil or LPG. Your installer claims it on your behalf.

Key specifications