Rinnai Infinity B20

The Rinnai Infinity B20 delivers 20 litres of hot water per minute, placing it firmly in the mid-to-large household category. It suits families of 3-4 people in homes with 2 bathrooms, and is recommended for properties where two outlets are commonly used simultaneously, such as a shower and a dishwasher, or two basins running at once. It is a popular choice in Perth four-bedroom homes and larger townhouses where the 16L/min models provide insufficient buffer for peak morning demand.

Both the Rinnai B20 and the Rheem 20 deliver 20L/min and carry 12-year heat exchanger warranties. The Rinnai B20 at $1,479 is $80 more expensive than the Rheem 20 at $1,399. The Rinnai B20 has a 6.1-star energy rating versus the Rheem 20’s 6-star rating, a slight efficiency advantage. Rinnai’s Puretemp temperature control and the Rheem Q Factor technology both aim to deliver consistent temperatures — they take slightly different approaches technically, but both perform well in practice. The Rheem 20 benefits from Ember’s additional 2-year extended warranty. Ember’s team can help you weigh up these differences for your specific situation.

Yes. Ember’s own blog post on Rinnai Infinity vs B Series confirms that the B20 and Infinity 20 use the same internal parts, including the heat exchanger, burner, and control board. The practical differences are the front panel display (Infinity has one; B Series does not), and to some degree the aesthetic finish. Both have a 6.1-star energy rating. The B Series is priced lower as a result of the simplified exterior, making it the more cost-effective choice for homeowners who prioritise performance over appearance.

The Rinnai B20 carries a 6.1-star energy rating. To put this in practical terms, Rinnai estimates that compared to a conventional 3-star gas storage hot water system, a 6.1-star continuous flow unit uses approximately one-third less gas per year. Over a typical Perth household’s annual hot water use, this represents a meaningful reduction in gas bills. The 6.1-star rating is achieved through electronic ignition (no standing pilot gas waste), Puretemp burner modulation, and on-demand heating with no standby losses.

At 20L/min, the Rinnai B20 can support two standard showers running at the same time (most showers use 7-9L/min each), leaving a small buffer. However, the effective output depends on incoming cold water temperature, in Perth’s warmer climate, the cold water supply is warmer than in southern states, which means the system achieves its rated flow at the set temperature more easily. In winter when cold water temperatures drop slightly, performance at full simultaneous load is still reliable. For three simultaneous outlets, the Rinnai B26 is the better choice.

Yes. Like all models in the Rinnai Infinity B series, the B20 is compatible with the optional Rinnai MC-601Q temperature controller. This wall-mounted controller allows you to set and adjust the hot water temperature from a convenient location inside the home — useful for households with young children, older residents, or anyone who adjusts their shower temperature preferences seasonally. Up to four controllers can be connected to a single B20 unit for temperature management across multiple areas of the home. Ask Ember at booking if you would like a controller included.