Everything you need to know about heat pump water heaters

At Cylinder Direct we’re all about sharing information to help you make informed and confident decisions about water heating methods and efficiencies. In this article, we’re going to focus on a different type of hot water cylinder system – the Heat Pump Water Heater (HPWH).

What exactly is a Heat Pump Water Heater?

It’s a way of heating the water in your cylinder using a heat pump, essentially extracting heat from the air outside. You may, therefore, hear them referred to as air-source heat pumps. They act like a refrigerator in reverse, using ambient heat from the outside air to heat water.

HPWHs are available as integrated, all-in-one systems, where the heat pump is part of the hot water cylinder. They are also available as split systems, where the hot water cylinder is located inside the house, and the heat pump is located outside.

HPWHs can be a bit noisy, so we suggest having them away from bedrooms (if using an integrated model inside) or outside away from bedroom windows (including the neighbour’s bedroom window).

Both Rheem and Rinnai, our trusted brands, have developed their products to reduce the noise caused by the air compressors, lowering the operating noise level somewhat since the early models.

Why would you use a Heat Pump Water Heater?

An HPWH is usually selected because of its energy-saving benefits. Instead of generating heat directly, they work by using electricity to move heat from one place to another.

An HPWH is a much more efficient way to heat water than standard electric or gas cylinders. According to the Smarter Homes website (administered by the Ministry of Business, Innovation and Employment): “Consumer NZ research shows that a well specified and installed heat-pump water heater would reduce your hot water bill by two-thirds over standard electric water heating.” (Source:

Because they rely on the heat of the outside air, heat pump water heaters work most efficiently at warmer outside temperatures (above 6-7°C). Additionally, as they remove heat from the air, they make the space they operate in cooler, meaning they tend to work more efficiently in a warm climate.

At Cylinder Direct, we can help you decide if a heat pump water heater is right for your property by looking at the following criteria:

  • the space and location available for your water heating
  • the fuel type or energy source you use for water heating
  • the energy efficiency needs and concerns for your household and usage
  • the budget – upfront costs as well as ongoing costs and cost savings

Models and brands of HPWHs available

Cylinder Direct offers a range of heat pump water heaters from our trusted brands Rheem and Rinnai. We can advise on what model is best for your property and water use. Feel free to have a look at the brochures here for Rheem and Rinnai.

We can also retrofit a heat pump to work with your existing conventional storage water heater.

A heat pump water heater must only be installed by a qualified professional. The team at Cylinder Direct is experienced and qualified to supply and install HPWHs. Remember, when you contact us, you deal with us directly. No subbies, no surprises!

Get in touch for a no-obligation chat about what’s best for your water heating.