Cylinder vs. Continuous Flow: what's right for your Auckland home?
We break down the running costs, install requirements and lifespan of each system so you can choose with confidence.
The two families of gas hot water
Almost every gas hot water system in Auckland falls into one of two camps: storage cylinders that keep a fixed volume of water hot around the clock, or continuous flow (also called instantaneous) heaters that fire on demand as you open a tap.
Both do the same job. The right choice depends on how many people live in the house, how many bathrooms run at once, whether you have gas already, and where the unit can physically be installed.
Gas hot water cylinders
Cylinders like the Rheem Stellar or Rinnai HotFlo store 130 to 300+ litres of hot water and use a burner underneath to keep it at temperature. You get strong flow to multiple outlets at once and a very quiet, simple system with a 10 to 15 year typical lifespan.
The trade-off is standing heat loss, the burner cycles on even when nobody is using hot water, and the footprint of the tank itself.
Continuous flow (instantaneous)
A Rinnai Infinity or similar unit mounts on an outside wall and only fires when a hot tap is opened. You never run out of hot water and standing losses are effectively zero, which usually makes them cheaper to run for smaller households.
Flow rate is finite though, a 26 or 32 model can comfortably run two showers on natural gas, but on LPG the same unit may only manage one at a time in winter.
Which one fits your place?
Big family, two showers at 7am, older home already piped for a cylinder: stick with a cylinder and size it 180L or larger.
Two-person townhouse, natural gas at the meter, wall space outside: continuous flow is almost always the better answer.
Off-grid or bottled-gas holiday home: continuous flow saves LPG, but check your bottle changeover setup.
