Vian Nexus Air Source Heat Pumps are purpose-built for hot tubs and swim spas. Whether you already have a spa or are planning to invest in one, adding a Vian Nexus heat pump is a smart, cost-saving upgrade.
As one of our most popular accessories, the Vian Nexus range has helped hundreds of owners cut their electricity bills while benefiting from quicker, more efficient heating. Designed for dependable performance and long-term savings, these heat pumps make an ideal addition to any hot tub or swim spa system.
Choose Vian Nexus for comfort, efficiency, and genuinely lower energy costs
Vian Nexus heat pumps are specifically designed for hot tubs and swim spas. Unlike generic heat pumps made for homes, the Nexus range is optimised for the flow, volume, and control systems used in spa environments.
Using advanced inverter and EVI (Enhanced Vapour Injection) technology, Nexus heat pumps deliver industry-leading COPs up to 14.2. That translates to more heat for less energy—and lower electricity bills.
Whether you’re in a mild or harsh climate, Nexus models deliver:
Nexus 5: works down to –10°C
Nexus 6: works down to –20°C
Nexus 7: works down to –25°C
This means greater reliability, even in winter.
Vian Nexus supports “hybrid” operation—using both the heat pump and your hot tub’s existing electric heater when needed. This is especially useful for:
Faster heating when demand is high
Quick heat-up between uses (e.g., in holiday rentals)
The Nexus units are compact and can be cleverly hidden:
Fit behind most hot tubs
Can be integrated into custom steps or housings
This gives you powerful heating without spoiling the look of your outdoor space.
With warm-core technology, Nexus models reduce ice build-up internally by gently heating the body and tray. This improves winter reliability and longevity.
Nexus heat pumps can integrate with Gecko and Balboa control systems (with the correct hardware), allowing for seamless communication, intelligent heating, and easy control.
Developed by UK Hot Tubs directors Avon Potter and Simon Clarke, the Nexus range was born out of real-world spa experience and a deep understanding of UK energy challenges. Their hands-on design ensures the range is truly built for spa owners like you.
Hundreds of spa owners have already installed Nexus heat pumps—and they are reaping the rewards through lower energy bills, longer spa sessions, and reliable heating.
Built with modern, efficient components and smart functions, Nexus heat pumps are designed to last and adapt. Investing in a Nexus means sustainability, reliability, and cost savings for years to come.
In short:
Choose Vian Nexus if you want a spa-specific, ultra-efficient, winter-proof, and intelligently designed heat pump that pays for itself in energy savings and gives you reliable performance when it matters most.
The Nexus 5 is an efficient, compact, and reliable heat pump in the Vian Nexus range—perfectly suited for smaller to medium-sized hot tubs and swim spas, especially in moderate climates.
Built for stable performance, the Nexus 5 operates smoothly even when outside temperatures drop to –10°C, making it well-suited to typical UK winters and temperate outdoor settings.
With full inverter and EVI (Enhanced Vapour Injection) technology, the Nexus 5 delivers a COP of up to 13, ensuring you get more heating power for less electricity—saving on running costs without compromising performance.
Designed for practical installation, the Nexus 5 fits neatly behind most hot tubs—even when a cover lifter is fitted. That means:
Hidden from sight
Doesn’t need additional space
Makes use of the space already used for the cover to drop down behind the tub
With smart modulation and inverter technology, the Nexus 5 maintains accurate and stable water temperatures, letting you enjoy your spa whenever you want without big fluctuations or energy waste.
Thanks to its thoughtful design and reliable engineering, the Nexus 5 is:
Simple to set up
Low-maintenance
Built for long-term dependable performance
Thanks to its communication options, the Nexus 5 integrates with major spa control platforms like Gecko and Balboa (when paired with the correct hardware), giving you control and flexibility.
Its inverter technology, robust build, and efficient components make the Nexus 5 a long‑lasting solution, delivering both reliability and consistent performance over time.
Choose the Nexus 5 if you want a cost-effective, compact, high-efficiency heat pump for a smaller or medium hot tub. It provides:
✔ COP up to 13
✔ Performance down to –10°C
✔ Quiet, discreet installation
✔ Stable temperature control
✔ Compatibility with Gecko & Balboa
Ideal for spa owners who want efficiency, reliability, and simplicity in a small package.
The Nexus 6 is a high-performance model in the Vian Nexus heat pump range, engineered for efficient and reliable heating in colder climates. It strikes a perfect balance between power, control, and energy savings for both domestic and commercial spa applications.
Equipped with EVI and heated bands, the Nexus 6 delivers consistent heat even when temperatures drop as low as –20°C. This makes it a dependable choice for:
Exposed outdoor installations
Regions with harsh winters
Users who want peace of mind during prolonged cold snaps
With a COP of up to 12.5, the Nexus 6 offers outstanding energy efficiency, helping you reduce electricity costs without compromising on heating power.
The Nexus 6 supports hybrid operation, meaning it can work alongside your hot tub’s 3 kW electric heater. This delivers:
Rapid temperature recovery
Ideal performance for high-usage environments (e.g. holiday lets or rentals)
Smart energy usage during steady-state heating
Thanks to Warm Core Technology, the Nexus 6 gently heats its internal body and tray to avoid ice build-up. This ensures:
Reliable operation in freezing conditions
Reduced maintenance and longer component life
Greater longevity and consistent performance
Though more powerful than smaller models, the Nexus 6 is designed to be integrated neatly:
Can be housed in a custom step or cabinet
Keeps the unit discreet and out of sight
Maintains garden aesthetics without compromising functionality
The Nexus 6 is fully compatible with leading spa control systems, thanks to a direct input switch for Gecko and Balboa platforms (when fitted with the correct hardware). This provides:
Seamless integration
Intelligent temperature control
Simple user experience
With robust components, inverter technology, and protective heating features, the Nexus 6 is built to last—delivering reliable performance through challenging conditions.
The Nexus 6 is an excellent choice if you want a powerful, efficient heat pump that can handle cold climates without sacrificing control or speed.
✔ Operates down to –20°C
✔ COP up to 12.5
✔ Hybrid logic for fast heat recovery
✔ Anti-ice warm-core protection
✔ Compact and discreet installation
✔ Compatible with Gecko and Balboa control systems
For spa owners who need reliability, efficiency, and speed in colder environments, the Nexus 6 delivers.
The Nexus 7 EVI is the flagship model in the Vian Nexus air source heat pump range, engineered for maximum performance, efficiency, and reliability in even the harshest conditions. It’s designed for hot tubs and swim spas where consistent warmth and energy savings are essential.
Thanks to EVI (Enhanced Vapour Injection) technology, the Nexus 7 can reliably operate in temperatures as low as –25°C. This makes it ideal for:
Exposed locations
Northern climates
Long-term outdoor installations
No other standard heat pump in its class delivers this level of cold-weather reliability.
The Nexus 7 achieves a COP of up to 14.2, meaning it produces more heat per unit of electricity than almost any other spa heat pump. This translates to:
Significant savings on energy bills
More cost-effective all-year-round heating
Faster payback on your investment
The Nexus 7 can work alongside your hot tub’s built-in 3kW electric heater, using it only when needed for rapid heat-up. This ensures:
Fast recovery after heavy use or water changes
Maximum efficiency during normal heating
Ideal performance for holiday lets, rentals, or busy households
Featuring a warm-core system, the Nexus 7 gently heats critical components such as the compressor body and tray to prevent ice build-up, ensuring:
Continuous operation in extreme weather
Reduced maintenance
Long-term reliability
Despite its superior output, the Nexus 7 is designed to be compact and space-efficient. When installed with a custom step or housing, it can be almost completely hidden, delivering high performance without compromising your outdoor space.
The Nexus 7 integrates with modern spa control systems such as Gecko and Balboa (when fitted with the correct hardware), allowing:
Intelligent heating management
Precise water temperature control
Easy integration with existing spa electronics
Uses modern inverter technology for smoother, quieter operation
Highly efficient, reducing energy waste and environmental impact
Designed to last and maintain performance in challenging climates
The Nexus 7 EVI is the ultimate heat pump for hot tubs and swim spas, offering:
✔ Extreme cold-weather capability (down to –25°C)
✔ Outstanding energy efficiency (COP 14.2)
✔ Fast hybrid heat-up when needed
✔ Anti-ice warm-core protection
✔ Seamless, discreet installation
✔ Smart compatibility with modern control systems
For anyone who wants maximum performance, reliability, and energy savings—especially in cold climates—the Nexus 7 EVI is the best choice in the Vian Nexus range.
An air source heat pump is an energy-efficient heating system that draws heat from the air to warm your hot tub or swim spa. It works alongside your existing system or replaces it, helping you heat your spa more efficiently and affordably.
If you use your hot tub or swim spa regularly, an air source heat pump can save you up to 75% on your energy bills. It’s a smart investment that provides reliable heating while reducing running costs.
Yes! They’re designed to perform efficiently in all seasons, even in colder UK weather, so you can enjoy your hot tub or swim spa any time of year.
We recommend Vian Power – a trusted, well-known brand that designs pumps specifically for hot tubs and swim spas. They’re reliable, efficient, and tailored to UK conditions.
Installation requires professional plumbing and electrical work, so it must be done by an experienced hot tub technician. We offer standard delivery and installation included within our service area.
If you’re considering upgrading your hot tub or swim spa with an air source heat pump, give us a call today on
UK Hot Tubs: 02382 687 005 | Spafix: 02393 541 154
Our friendly, knowledgeable team is always happy to help with any questions or advice you need — and we’ll get back to you as quickly as possible.
Do I need additional electrical work?
No extra electrics are needed! The heat pump draws power directly from your hot tub or swim spa, so there’s no need for a separate supply.
Do I need planning permission?
No planning permission is usually required. However, every installation is different, so we offer a free site survey (for local clients) to assess the best location and setup for your heat pump.
What’s involved in the installation?
Our technician will make some simple modifications to your hot tub or swim spa, adding an inlet and outlet pipe to allow water to circulate through the heat pump for efficient heating.
Where does the heat pump need to be placed?
The unit needs a minimum of 450mm of clear space for air intake, and at least 1500mm in front of the fan outlet to ensure proper airflow and performance.
Due to how the system works, our air source heat pump will still produce heat even if the ambient air temperature is below zero as the compression of the refrigerant creates heat. Not only is this a far more cost-effective solution to heat your hot tub, it is also a much more eco-friendly option.
The chart below shows the kilowatt hours (kWh) used by the air source heat pump to maintain a constant water temperature of 40°C. The test was carried out over a 31-day period, running from the 8th of December 2022 to the 7th of January 2023.
This proved to be an ideal timeframe for performance testing, as it began during a particularly cold spell in the UK, with temperatures dropping several degrees below freezing. On the 10th of December 2022, for example, the recorded ambient temperature was -3.1°C. As shown in Figure 1, the heat pump used 5.62 kWh of electricity on that day to maintain the desired temperature.
By comparison, later in the test period, on the 4th of January 2023, the outside temperature had risen to 11.5°C. As seen in Figure 2, the heat pump used just 1.66 kWh to maintain the same water temperature of 40°C.
In total, the heat pump consumed 116.21 kWh over the full 31-day period, giving an average daily usage of 3.75 kWh. These results clearly demonstrate that as the ambient air temperature increases, the efficiency of the heat pump also improves significantly, making it a highly effective and energy-conscious solution for heating hot tubs and swim spas—even during colder UK winters.
The performance test was carried out in Chichester, West Sussex, UK with a Vian 7kW S7 Plus Air Source Heat Pump. During the test, the electric heater was fully disconnected, ensuring that all heating was supplied by the heat pump alone.
The hot tub used for the trial is a mid-specification model with a capacity of approximately 1,550 litres, located outdoors and completely unsheltered.
To reflect more realistic, everyday usage, the tub was fitted with an older, slightly waterlogged cover, and the pipes leading to the heat pump were not insulated. The heat pump was positioned within one metre of the hot tub.
The heat pump was set to operate in boost mode, and programmed to maintain a water temperature of 40°C. For energy management purposes, the hot tub followed an economy cycle that prevented it from heating between 10:00 PM and 10:00 AM daily, and again from 1:00 PM to 4:00 PM, seven days a week.
To calculate the heating cost, we used the Ofgem rate of 27.35 pence per kWh (as of 1st October 2023).
On 10th December 2022, with temperatures below zero, the heat pump used 5.62 kWh, costing £1.53.
By comparison, on the 4th January 2023, with milder temperatures of 11.5°C, it used only 1.66 kWh, costing £0.45.
Over the 31-day test period, the average daily usage was 3.75 kWh, equating to an average daily cost of £1.03.
We continued monitoring the heat pump’s energy usage throughout the winter, spring, and summer months, covering a 10-month period from 8th December 2022 to 7th September 2023. The chart and table below display the total kWh consumed by the hot tub’s air source heat pump each month during this time.
In Summary
Over the 10-month test period, the heat pump used a total of 749.55 kWh. This resulted in an average monthly consumption of 74.96 kWh, costing approximately £20.50 per month.
When broken down to a daily average, the heat pump used 2.46 kWh and cost just £0.67 per day, based on a 365-day year.
Overall, the total cost for 10 months of usage was £205.00 at the current rate of 27.35 pence per kWh.
From 1st October 2023 new kWh rate will be set at 27.35p website reference (Ofcom)
These recordings and data are only for representative purposes as there are so many variables with different locations, temperatures and usage that could result in different figures.
Whilst not independently vetted, we have performed this test to measure the kWh power consumption of our Vian 7kw S7 plus heat pump to show some of the real-world results.
We used a simple inline kWh meter that connects to a smart home system to measure and record the usage.
We chose to undertake this testing during the colder months and incorporate a very cold period of weather to record the results in these conditions. As the ambient temperature increases through the seasons then the efficiency of the heat pumps will increase, and the kWh usage will reduce as can be seen with the longer-term testing results.
Our figures and recordings are only relating to the consumption of the air source heat pump. Whilst fitting an air source heat pump to your hot tub or Swim Spa will significantly reduce overall running costs it will only reduce costs pertaining to heating.
We believe it is clear to see that a Vian Power Heat Pump is an extremely efficient heating solution for your hot tub or Swim Spa.
Sale ends 1st December
All hot tubs to be delivered before we close for Christmas
