Aquark Mr Silence Hot Tub & Swim Spa Air Source Inverter Heat Pump 9kW

Mr Silence is built around one idea: heat your water quickly, then get quiet. An airstream-optimised casing and a twin-rotary Mitsubishi DC inverter compressor let it run from 36.5 dB(A) at low speed, roughly the level of a domestic fridge, so it can sit near a terrace or under a bedroom window without dominating the garden.

At the start of a session it works at full output to bring the water up to temperature. As it closes on your set point it steps the compressor down, which is where the efficiency sits: at reduced speed the unit reaches a coefficient of performance of up to 14, meaning up to 14 kW of heat delivered into the water for every 1 kW of electricity drawn.

Why choose this unit

Inverter, not on-off. A fixed-speed heat pump only knows full power or nothing, and cycles hard to hold temperature. This one modulates, so it holds your set point steadily, draws less power doing it, and runs far quieter once up to temperature.

Titanium heat exchanger. The water side is twisted titanium rather than coated steel. Titanium is unaffected by chlorine, bromine and salt-chlorinated water, so treated spa water will not corrode it.

Works through the British winter. Rated to operate down to −10°C ambient. Output and efficiency fall as the air gets colder, which is why two sets of figures are published below rather than one headline number.

App or panel control. Set and monitor temperature from the onboard panel or from your phone, so you can bring the water up before you get home.

Performance

Heat pump output and COP are always quoted against stated air, water and humidity conditions, because performance changes with all three. Below roughly 15°C ambient the unit will take longer to reach your working temperature.

Build and connection

How an air source heat pump works

A heat pump does not generate heat, it moves it. A fan draws ambient air across an evaporator coil carrying refrigerant. Even cold air holds usable energy, and the refrigerant boils off at low temperature as it absorbs that energy.

The compressor then squeezes that gas, which raises its temperature sharply. The hot gas passes through the titanium heat exchanger, giving up its heat to the water circulating from your hot tub or swim spa. The refrigerant condenses back to a liquid, passes through an expansion valve, and starts again.

Because the electricity is only powering the fan and compressor rather than heating the water directly, you get several times more heat out than you put in. That ratio is the COP, and it is the reason a heat pump costs a fraction of an electric element to run.

Before you order

The unit needs a level, free-draining base with clear airflow around the fan and casing, and a position where the discharge air is not blowing straight into a wall or fence. Electrical connection is to a 230V single-phase supply and must be carried out by a qualified electrician. Water connections into your existing spa circulation should be made by a competent installer.

Delivery

Dispatched within 5 to 7 days. Kerbside delivery to UK mainland. At 55 kg you will want a second person on hand to move it into position.

Backed by our 30 day satisfaction guarantee.

See it in action