Rinnai or Rheem hot water heating systems which one is better

Rheem vs Rinnai

If you’re doing your own research on hot water heating systems, you may be reading about gas vs electric, hot water cylinder vs continuous flow hot water system, indoor vs outdoor hot water cylinders. You’re probably finding that two brand names keep popping up – Rheem vs Rinnai hot water cylinders.

There are a few other smaller brands available that provide quality, reliable products. But most of the information available focusses around these two main brands. Because we receive a lot of questions around which brand is better, Rinnai or Rheem, we’ve put together a comparative summary here to answer some of your questions and to help inform your decision making.

Difference between Rheem vs Rinnai hot water cylinders

Let’s start with full disclosure here – we at Cylinder Direct do not get paid by either brand to promote or advertise their products. We purchase their products directly from them, and then install, maintain, repair, replace them for you the customer. We’re not incentivised by the suppliers to choose one brand over the other.

How do we choose between Rinnai and Rheem for hot water systems?

When we look at which brands to work with, our evaluation process focusses on:

  • quality and reliability of their products
  • customer reviews and feedback (here in NZ and overseas)
  • price and value for money
  • service, support, training, customer help available from supplier
  • warranties available
  • range of products available
  • ease of installation, ease of use, ease of maintaining and repairing
  • availability of parts and components
  • company values, brand values
  • brand innovativeness, forward-thinking, proactiveness
  • company sustainability initiatives

It’s quite a long list, when you stop to think about it. We don’t make decisions lightly at Cylinder Direct. We prefer to work with suppliers who share our values and who are proactive about providing value for the customer.

When we use the above criteria to evaluate whether Rinnai is better than Rheem, or Rheem is better than Rinnai, the answer is … neither.

The two brands are top choice for us. We can honestly say that one is not better than the other.

On the other hand, one might be better for you and your needs. It all depends on what your objectives and needs are.

It’s a bit like asking whether apples or oranges are better for you. Which one is better, chicken or fish? White wine or red? We love them all. One is not better than the other based on their features. But when you evaluate them against specific objectives, you may uncover preferences.

Let’s compare Rheem vs Rinnai hot water cylinders




Hot water cylinders – low pressure

Hot water cylinders – mains pressure

Availability of copper, stainless steel, enamel

Size range for residential cylinders

30 – 300 L

25 – 300L

Smart Cylinder™


Installation location



Domestic warranty: Cylinders/tanks

10 years

10 years

Continuous flow gas hot water heating

Domestic Warranty: Heat Exchanger (Parts/Labour)


10/3 years

EZiSET® smart phone remote control system


Heat Pump Water Heating


Two main differences between Rinnai and Rheem hot water cylinder

On the whole, the product offerings from Rinnai and Rheem are very similar, with the range of choice and the warranties available all being excellent.

The only place we can find an obvious difference between Rinnai and Rheem is in their proprietary products that they’ve introduced. These are:

  • Rheem – the EZiSET® system allows you control your Gas Continuous Flow Water Heater remotely from your smartphone. You can set your ideal water temperature and bath level (handy if you need to control water temperature or usage while some else is in the home – great if you have tenants or operate a holiday rental property). Note, some models of smart phones are not compatible. Refer to the product sheet here.
  • Rinnai – the Smart Cylinder™ is an Electric Hot Water Cylinder designed to help you save money on your power bills. It monitors the household’s hot water usage behaviour and only heats the water as and when it’s needed (as opposed to heating all of the water in the cylinder 24/7). The Smart Cylinder™ has three modes: IQ, Manual and Vacation. Refer to the product brochure here.

Whether these options make one brand “better” than the other comes down to personal preference and what you want/need for your household. If you’re using a continuous flow hot water heating system (or are thinking of upgrading to one), the Rheem EZiSET® system might be something that sways you towards Rheem. If an electric hot water cylinder is best for your property, and you’re interested in lowering your power bills, the Rinnai Smart Cylinder™ might be what attracts you to Rinnai.

We’ve installed both of these and are happy to discuss with you the great feedback we’ve had with both.

A bit more about the history of Rinnai and Rheem

Rinnai is a public company based in Nagoya, Japan. It was started in 1920 by two childhood friends, with an oil-based cooking stove as their first product. The product line evolved into gas stoves, ovens and heaters. They now specialise in home heating/cooling, water heating and commercial services. Rinnai has been in New Zealand since 1975 and has their NZ head office in Mangere, Auckland.

Rheem was started in the United States in the 1920s. It is a private company headquartered in Atlanta, Georgia. They specialise in residential and commercial water heaters and boilers, as well as heating, ventilating and air conditioning (HVAC) equipment. Rheem has been in New Zealand since 1958, and has their NZ head office is Avondale, Auckland.

Both Rinnai and Rheem continue to expand globally, focussing on plumbing, heating and appliances. At Cylinder Direct, we proudly supply and install both brands, and enjoy a great relationship with both companies.

In summary, then, both Rinnai and Rheem are fantastic with reliable products that we trust for our clients.

Get in touch with the knowledgeable team at Cylinder Direct for a no-obligation initial chat and we’ll help you determine what’s best for your home and your budget. Have a look at our Hot water cylinder installations page – then contact us.