Rinnai vs Rheem — Best Hot Water Brands in NZ

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Rinnai — NZ's Continuous Flow Leader

Rinnai is New Zealand's most popular gas continuous flow hot water brand. The Rinnai Infinity range — available in A20, A26, and A32 models — is the go-to choice for gas instant hot water across Auckland. The Rinnai Infinity A26 is the unit we install most often: it delivers 26 litres per minute, enough for two showers running simultaneously, and comes with a 12-year heat exchanger warranty from Rinnai NZ.

Rinnai continuous flow systems heat water on demand using electronic ignition — there is no stored tank, no standby heat loss, and no running out of hot water. For Auckland homes with an existing gas supply, a Rinnai Infinity is the most efficient way to get unlimited hot water. Japanese engineered with parts widely available through NZ plumbing suppliers, Rinnai units are straightforward to service and maintain.

Rinnai also manufactures the Enviroflo and HydraHeat integrated heat pump ranges for homeowners looking to move away from gas entirely. These are electrically powered and can reduce hot water running costs by up to 75% compared to a standard electric cylinder.

See our Rinnai Infinity guide for a detailed breakdown of the range, or view the heat pump range for Rinnai Enviroflo and HydraHeat.

Rheem — NZ's Electric & Gas Storage Leader

Rheem is the most common hot water cylinder brand in New Zealand. If your Auckland home was built in the last 30 years, there is a good chance it came with a Rheem electric cylinder. They are solid, reliable, and affordable — the straightforward choice when your existing cylinder needs replacing. The Rheem Optima range covers mains pressure and low pressure configurations from 135L to 300L.

For gas storage hot water, the Rheem Stellar Outdoor range is the direct replacement for old Vulcan Freeloader cylinders — available in 130L and 160L sizes. The Stellar is manufactured in Australia, runs on natural gas, and comes with a 10-year cylinder replacement warranty from Rheem NZ. It uses Rheem's SuperFlue technology for improved efficiency and a vitreous enamel lining for long-term corrosion protection.

Rheem also makes the Integrity 27 continuous flow unit (a solid gas instant alternative to Rinnai) and the AmbiPower and AmbiHeat integrated heat pump ranges for homeowners looking to reduce their power bills by up to 75%.

See our electric cylinder guide, gas storage guide, or heat pump range for detailed product breakdowns.

Rinnai vs Rheem — Which Should You Choose?

Both brands are excellent. The right choice depends on your fuel type, household size, and what you are replacing:

• Replacing an old gas califont or want unlimited hot water? — Go Rinnai Infinity. The A26 suits most Auckland homes.
• Replacing an old electric cylinder? — Go Rheem Optima. Match the existing size and pressure type.
• Replacing an old Vulcan gas cylinder? — Go Rheem Stellar. The 130L or 160L drops straight in.
• Want the lowest running costs long-term? — Go heat pump from either Rheem (AmbiPower) or Rinnai (Enviroflo).

Not sure which direction to go? Give us a call and we will talk you through the options based on your home and usage. See our cylinder replacement guide for more detail on the switchover process.

For the full brand comparison and pricing, visit wgw.co.nz/hot-water/brands

Frequently Asked Questions

Which hot water brand is most reliable in NZ?

Rheem and Rinnai are the two most widely installed hot water brands in New Zealand. Rinnai dominates the continuous flow market with the Infinity range, while Rheem leads in electric cylinders and gas storage with the Stellar range. Both have strong NZ warranty support and readily available parts.

Is Rinnai better than Rheem for hot water?

They excel in different areas. Rinnai is the leader in gas continuous flow — the Infinity A26 is the most popular unit we install. Rheem leads in electric cylinders and gas storage — the Rheem Stellar is the go-to replacement for old Vulcan gas cylinders. For gas continuous flow, go Rinnai. For cylinder replacement, go Rheem.

What warranty do Rinnai and Rheem hot water systems come with in NZ?

Rinnai Infinity units come with a 12-year heat exchanger warranty. Rheem Stellar gas storage cylinders come with a 10-year cylinder replacement warranty. Rheem electric cylinders typically carry 5-10 year warranties depending on the model. We register all warranties on installation day.

What brands of hot water system do you install in Auckland?

We primarily install Rinnai and Rheem — the two most trusted hot water brands in New Zealand. Rinnai for continuous flow gas systems and Rheem for electric cylinders, gas storage, and heat pump hot water. We can source other brands on request.