The Vaillant aroTHERM Plus is one of the most widely installed heat pumps in the UK, and for good reason. As a Vaillant Renewables Partner covering London, Green Electro Heating installs the full aroTHERM Plus range with access to the extended 7-year manufacturer warranty on qualifying installations. This guide covers what makes the Vaillant heat pump stand out, what sizes are available and what to expect from an installation in London.

What Is the Vaillant aroTHERM Plus?

The Vaillant aroTHERM Plus is a monobloc air-to-water heat pump, meaning all components are contained in a single outdoor unit with no indoor refrigerant pipework required. Designed for both new build and retrofit properties across the UK, it uses R-290 refrigerant with a Global Warming Potential of just 3, making it one of the most environmentally responsible heat pumps currently available.

The aroTHERM Plus can deliver flow temperatures of up to 75°C, which means it is compatible with most existing radiator systems without requiring costly upgrades. This makes it a practical choice for a wide range of London properties, from Victorian terraces to modern homes.

Vaillant aroTHERM Plus Key Specifications

• Available outputs: 3.5kW, 5kW, 7kW, 10kW and 12kW
• Refrigerant: R-290 (GWP of 3)
• SCOP: up to 5.03 at 35°C flow temperature (10kW model)
• Maximum flow temperature: 75°C
• ErP rating: A+++ (highest available energy efficiency classification)
• Quiet Mark accredited for low noise operation
• Compatible with Vaillant uniSTOR hot water cylinders and smart controls

The SCOP of up to 5.03 means that for every 1kWh of electricity used, the system delivers up to 5.03kWh of heat across an average year. This is the Seasonal Coefficient of Performance, a measure of annual average efficiency rather than a snapshot reading, making it a reliable guide to real-world running costs.

What Sizes Are Available and Which Is Right for My Home?

The aroTHERM Plus comes in five output sizes from 3.5kW to 12kW. The right size is always determined by a full room-by-room heat loss survey rather than property size alone, since two homes of identical size can have very different heating demands depending on construction, window areas and ceiling heights.

As a general guide, a 5kW unit suits smaller homes and flats, a 7kW suits most 3 to 4 bedroom London homes, and the 10kW or 12kW is suited to larger properties or those with higher heat demand. A proper heat loss survey before installation is the only reliable way to confirm the right specification.