Rinnai HydraHeat Hot Water Heat Pump

The experts in water heaters and heat pumps have combined the technology of both to bring you a very clever solution - a Hot Water Heat Pump called HydraHeat™. Using the efficiency of heat pump technology, HydraHeat™ will heat a home’s water while saving you up to 75% on your water heating costs*. The result is a far more cost-effective and more sustainable solution for the homes of tomorrow. Designed and built right here in New Zealand for Kiwi conditions, HydraHeat™ is easy to install for any home.

  • Category
    Heat Pumps, Hot Water Cylinders
  • Range
    Heat Pumps
  • Year
  • Country of origin
    New Zealand
  • Type of use
    Commercial and Residential
  • Installation
    Professional installation required

Storage capacity: 275 L

COP:4.7 W/W*
(inlet water temp 19 ºC, outlet water temp. 55 ºC, ambient temp. 19 ºC)

* Accredited Testing to AS/NZS 5125 Pending by NATA accredited Provider.

Rated heat pump input/output: 802 W / 3725 W
In standard, eco 50/55 modes, the heat pump provides 100% of the heating within the operating range. Outside these limits, the electric element will operate.

Hot water recovery rate: 89 L/h
The recovery rate is calculated at Eco 55 mode, 19 ºC ambient temp., 41 ºC rise.

Cylinder element rating: 2 kW

Cylinder construction: Enamel

Operating temperature: -10 to 42 ºC

Noise level: 45 dB(A)
Sound pressure level measured at 1 m distance from the water heater in a free field. The appliance operated in standard mode (60 ºC) at an ambient temperature of 19 ºC.

Refrigerant type: R290 / 150 g (A3 flammable)

People per household: 2-6

Modes of operation:

  • Standard (factory preset) water stored at 60 ºC
  • Boost, a one-off electric boost to 70 ºC
  • Eco 55, water stored at 55 ºC
  • Eco 50, water stored at 50 ºC
  • High usage, water stored at 70 ºC (heat pump + electric element)
  • Element only (heat pump turned off, electric element heats water to 70 ºC
  • Shutdown (in standby, heat pump and electric element are turned off)


  • Assembled: Height - 1750 mm, diameter 692 mm
  • Heat pump header: Height 510 mm
  • Cylinder: Height 1240 mm

Water supply and connections

  • Min. inlet water pressure - 100 kPa
  • TPR (supplied) - 850 kPa
  • Cold water expansion valve - 700 kPa
  • Pressure limiting valve - 500 kPa


  • Heat pump header - 38 kg (net), packaged 47 kg
  • Cylinder - 87.5 kg (empty), 362.5 kg (full)
  • Full system - approx. 400 kg

IP rating: IPX4 header and cylinder

Market release Nov 2023

Scope of use

Primarily designed for residential applications, but can be used for smaller commercial applications.

Not suitable as a spa or swimming pool heater, or for hydronic applications. Hard and acidic water will need to be treated to use this product, refer to water quality parameters in the support material (downloads).

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About the

For over 45 years, Rinnai has supplied New Zealand homes with a range of appliances that help Kiwis to enjoy comfortable, safe and efficient lives. We’ve designed and manufactured products especially for New Zealand homes and conditions – from heating your water, to heating and cooling your living areas. With over a million appliances sold over this time, Rinnai has established a proud reputation for quality and reliability, and become known as your total home living experts.

At Rinnai, we’re all about comfort.