Vian Nexus Air Source Heat Pumps are designed specifically for hot tubs and swim spas. Whether you already own a hot tub or swim spa, or you’re planning to purchase one, adding a Vian Nexus heat pump is a smart and cost-effective upgrade.
As one of our best-selling accessories, Vian Nexus heat pumps have already helped hundreds of customers significantly reduce their electricity costs while enjoying faster, more efficient heating. Engineered for performance, reliability, and long-term savings, the Nexus range is the perfect companion for any hot tub or swim spa setup.
Make the smart choice—choose Vian Nexus for efficiency, comfort, and real energy savings.
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.
Installing a Nexus air source heat pump is a specialized process that requires the expertise of a qualified hot tub technician. Our team ensures every installation is safe, efficient, and tailored to your spa setup.
Air source heat pumps involve both plumbing and electrical connections, so proper installation is critical for:
Safe operation
Optimal heating performance
Longevity of your equipment
All installations are completed by experienced technicians with extensive knowledge of hot tubs and swim spas.
All our pricing includes standard delivery and installation within our coverage area, so you know exactly what you’re paying for—no hidden costs.
Our Nexus heat pumps represent the latest in UK hot tub heating technology. They have been:
Extensively tested to ensure reliability
Reviewed highly on Checkatrade, reflecting our customers’ satisfaction
This means you can trust the product and our installation service.
Starting from £1,344 and available in a range of sizes, Nexus heat pumps can be fitted to:
Small to medium-sized hot tubs
Larger swim spas
Most standard UK spa designs
By combining UK Hot Tubs’ extensive experience with high-quality equipment, every Nexus heat pump installation is:
Safe and compliant
Optimized for performance
Designed to maximize energy efficiency
Fitting a Nexus air source heat pump is more than just plugging in a device. With professional installation included in our pricing, fully tested UK-ready technology, and flexible sizing for most tubs and spas, you can enjoy:
✔ Safe, reliable installation by experts
✔ Energy-efficient, cost-saving heating
✔ Proven technology with great customer reviews
✔ A solution tailored to your spa
If you want to enjoy your hot tub or swim spa more often, more affordably, and more efficiently, then a Nexus Air Source Heat Pump is the smartest upgrade you can make.
You’ll benefit from:
✔ Significant energy savings
✔ Faster heating times
✔ Reliable performance in cold weather
✔ Quiet, efficient operation
✔ Lower long-term running costs
Unlike many “generic” air source heat pumps, the Nexus range is designed specifically for hot tub and swim spa applications. This means:
Correct flow rates
Compatible control logic
Efficient low-volume heating
Seamless integration with modern spa systems
No compromises—just optimal performance.
The Nexus models offer industry-leading COP values, with the top model achieving a COP of up to 14.2.
This means:
More heat for every unit of electricity
Lower running costs
Faster return on investment
Most standard heat pumps can’t match this efficiency across real-world spa conditions.
With advanced EVI and inverter technology, Nexus heat pumps outperform competitors in cold climates:
Nexus 5: down to –10°C
Nexus 6: down to –20°C
Nexus 7: down to –25°C
This allows stable, reliable heating long after other heat pumps lose performance.
The Nexus range can work in harmony with the hot tub’s existing 3kW electric heater, providing the ideal blend of:
Speed (rapid heat-up when needed)
Efficiency (heat pump as primary source)
Perfect for holiday lets and high-turnover environments.
Each model is engineered with practical installation in mind:
Compact units fit behind most hot tubs
Larger models can be hidden inside custom steps or housings
Minimal visual impact with maximum heating performance
No bulky equipment ruining your garden space.
The Nexus range includes internal heating protection to prevent ice build-up in extreme weather.
This increases:
Reliability
Lifespan
Winter efficiency
A feature rarely found on standard heat pumps.
Nexus heat pumps integrate seamlessly with:
Gecko systems
Balboa systems
(using the correct hardware), enabling:
Direct communication
Intelligent heating logic
Simple, user-friendly control
Not all heat pumps offer this level of plug-and-play compatibility.
The Nexus range was developed with real-world UK spa usage in mind, informed by:
Rising UK electricity costs
Harsh winter conditions
Customer demand for efficiency and reliability
This results in a product range that solves actual spa-owner problems—not just theoretical ones.
These heat pumps are already one of the best-selling hot tub accessories, with hundreds of satisfied users benefiting from:
Lower running costs
Quieter operation
Longer equipment life
Better temperature control
The track record speaks for itself.
With inverter technology, EVI systems, smart integration, and highly efficient components, Nexus heat pumps are built to remain relevant, efficient, and reliable for years to come.
If you are interested in finding out more about the range of Vian Nexus Air Source Heat Pumps we offer, why not call us today on 02382 687 005
Our team would be delighted to help you with any questions or queries you might have, and we will endeavour to get back to you as soon as we can.
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 kWh used by the heat pump to maintain the set point of 40°C. The test period is for 31 days between the 8th Dec 2022 and the 7th January 2023.
This was an ideal test period as the beginning of the test on the 8th Dec 2022 the UK experienced a very cold spell with temperatures dropping several degrees below zero.
Figure 1 shows the recorded temperature on the 10th of Dec 2022 of -3.1°C and the chart shows the kWh usage of 5.62kWh. Compared to figure 2 showing the temperature for the 4th of Jan 2023 being 11.5°C the kWh usage reduced to only 1.66 kWh.
The total kWh used by the heat pump over this period was 116.21 and this equates to an average of 3.75 kWh per day. As the ambient temperature rises, we can easily see that the efficiency of the heat pump increases significantly.
To equate these kWh figures to a cost, we use the current price per kilowatt hour as a multiplier. Currently at the time of updating this case study the new kWh rate as per Ofgem is: 27.35 pence per kWh (1/10/2023)
10th December 2022, a cold day where we experienced temperatures below zero – kW usage = 5.62kWh used / Heating cost = £1.53
For comparison on the 4th January 2023 we had much a warmer temperature and the kW usage was only 1.66 equating to a cost of £0.45p.
The total average daily Kilowatts used during this winter test period of 31 days equated to 3.75 kW meaning the average daily cost of the heat pump was only £1.03p.
Looking at further long-term results we continued to measure the heat pump consumption through the winter, spring, and summer months.
At the time of updating this case study we can report on a ten-month period of testing. This period covers the initial 31-day test period from 8th December 2022 up to the 7th September 2023.
The chart and table below show the total kilowatts consumed by the hot tub air source heat pump by month during this period.
IN SUMMARY
We can now look at a long period of results covering warm and cold months to determine an average overview of the consumption and cost experienced when using the Vian S7 air source heat pump to heat the hot tub.
The total kilowatts used by the air source heat pump over this period was: 749.55.
Resulting in an average monthly kW use and cost of 74.96 kW / £ 20.50.
Resulting in an average daily kW use and cost of 2.46 kW / £ 0.67p when we gross this data over a year and averaging by 365 days.
Quite incredibly these figures mean that the total cost of the air source heat pump consumption over the ten months test period equates to £205.00 at a rate of 27.35 pence per kilowatt hour.
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.
