Hot Water Heat Pumps

Hot water heat pumps are an energy-efficient and low-emissions technology that significantly reduces household water heating costs.


Frequently Asked Questions

Euroheat - The difference between split and integrated hot water systems.
A cross-section image of the inside of a hot water heat pump to demonstrate how a domestic hot water heat pump works, including the compressor, evaporator, exhaust fan, hot water outlet, cold water inlet, heated refrigerant from compressor.

Images from EECA.

Rinnai HydraHeat™ Hot Water Heat Pump

Rinnai logo for Hot Water Heat Pumps

Rinnai has designed HydraHeat, a top-notch integrated system powered by only 150g of high-efficiency refrigerant, making it one of the most sustainable options on the market.

Operating much like a refrigerator in reverse, the HydraHeat™ utilises the surrounding air’s ambient temperature and amplifies this energy to heat water at significantly reduced costs compared to conventional hot water cylinders.

Rinnai HydraHeat mains pressure integrated hot water heat pump system.
  • Designed and Built in NZ Specifically designed for New Zealand climatic conditions (from - 10°C to +42°C), as well as coastal locations.Operates in full heat pump mode right down to - 10°C without the need for electric boosting.

  • Up to 75% Savings on Hot Water Costs* Provides highly efficient water heating, minimising energy consumption and lowering operating costs.

  • Dedicated to Sustainability Powered by only 150g of high-efficiency R290 refrigerant with low Global Warming Potential and COP of 4.7.**

  • Reliability The inbuilt electric element guarantees a consistent and dependable supply of hot water, at all times.

  • Modular 'Heat Pump Ready' Design Ability to upgrade from a standalone electric water heater to Heat Pump Technology with addition of Heat Pump unit.

  • Easy Servicing Removable Heat Pump unit allows for easy servicing, and ensures uninterrupted supply of hot water.

  • Frost Protection Built-in defrost and frost protection functions to handle colder climates.


  • Warranties 5-year head unit warranty and a 7-year cylinder warranty.

  • User-friendly Control Interface Features OLED screen and six operation modes for versatility.

  • 6 Operation Modes Standard, Boost, Eco 55, Eco 50, High Usage, and Element Only.

  • Suitable for Hard or Soft Water Areas Featuring an enamel cylinder with a magnesium anode for effortless use in both hard and soft water areas.

  • Ideal for a Range of Residential Styles Suitable for homes of 2–6 people. Plus an operating sound level of only 45dBA makes it suitable for a wide range of homes, including built-up residential areas.

  • Renowned Quality Crafted with exceptional quality by Rinnai New Zealand, the trusted name in total home living.

  • * Compared with a standard hot water cylinder in Zone 5 (Auckland). Annual energy performance estimated according to AS/NZS4234:2008 and AS/NZS5125:2014, medium load size. ** Accredited Testing to AS/NZS 5125 Pending by NATA accredited Provider.

    How many kW are used in a Rinnai HydraHeat Hot Water Heat Pump Integrated system

    Split Systems

    The Mitsubishi Range

    Mistubishi Electric logo for hot water heat pump split systems

    Mitsubishi’s Black Diamond AquaCore heat pump system is made with local conditions in mind and can operate in a wide temperature range from -15°C all the way up to 45°C.

    The Ecodan Co2 QUHZ model has a dedicated pre-plumbed 200L thermal store with low noise output and built-in energy monitoring.

    Made in New Zealand

    Coefficient of Performance, COP (AS/NZS 5125.1) = 4.0

    Refrigerant = R32 GWP of 675 (Global Warming Potential)

    Hot water production up to 70ºC

    Mitsubishi BDT Black Diamond AquaCore Hot Water Heat Pump installation by Euroheat

    Mitsubishi BDT Black Diamond AquaCore Hot Water Heat Pump

    • Split system with bespoke outdoor unit, can be used with new or preexisting cylinder

    • WiFi control

    Mitsubishi Ecodan Co2 QUHZ Heat Pump and Cylinder Installation by Euroheat

    Mitsubishi Ecodan Co2 QUHZ Heat Pump and Cylinder

    • Split system

    • 4kW output