Exhaust air heat pump extends the options

from Ariston

The NUOS exhaust air heat pump is a brand new type of renewable technology that has joined the Ariston range.

The NUOS is similar in appearance to a regular electric wall-hung cylinder, only it incorporates an air source heat pump into its design. The heat pump, situated at the top of the unit, transfers the heat from the ambient air into the cylinder, heating the stored water to a temperature of 55°C.

As a result, impressive energy savings of up to 67% can be achieved compared to traditional electric storage water heaters. The NUOS offers the option of up to 10m of ducting, allowing the appliance to be installed in an alternative location to the area from which heat is being extracted. The most suitable areas from which to extract heat in a domestic setting are places such as utility rooms, kitchens, bathrooms or, for larger properties, separate plant rooms, all of which may generate excess heat that can be utilised.

The NUOS also offers benefits to installers who are interested in offering renewable energy options to their customers. “While it is great news that an increasing number of renewable products are being developed, installers must always consider the issue of training in order to become competent in the installation of new technology,” said Gareth Ash, Product Manager.

“That is where the NUOS comes into its own, as the installation process bears many similarities to installing a regular cylinder. With just a small amount of time spent familiarising themselves with the technology, installers are able to offer householders an energy saving option that does not require them to invest in long periods of specialist training to become qualified. Consequently, the NUOS offers benefits and savings to householder and installer alike.”

The NUOS offers different operating settings, thanks to the backup heating element within the appliance. This has an output of 1.2kW and can be used to ‘top up’ the water temperature if necessary. ‘Eco-mode’ is the default setting for maximum energy savings, whereby the water temperature is increased and maintained only by the heat pump, with automatic switching to ensure the desired temperature is reached at the programmed time.

Alternatively, the ‘override’ function can be chosen whereby both the element and heat pump work together to heat the water if required quickly. Although this is naturally a less energy efficient option, it is still around 30% more efficient than a standard electric water heater. Once the system has reached temperature, the fast mode is automatically deactivated, preventing accidental prolonged use of the immersion when not required. Periodically, an anti-bacterial function boosts the temperature of the water in the cylinder just above 60°C to pasteurise the system.


The NUOS has been designed for ‘plug and play’ installation for those competent in installing unvented cylinders.  The only difference is that this heat pump technology requires an air exhaust, which takes the air that has been cooled after transferring its heat energy to the water cylinder and disperses it outside, so as not to pump cool air into the house.  Ariston offers the appropriate kits and accessories to assist with installation.

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