7 Reasons to Choose Tankless Instantaneous (Instant) Gas Hot Water System

Last Updated August 27, 2026
TL;DR • Quick Summary
  • Tankless gas systems heat water on demand, so you get continuous hot water with no waiting for a tank to reheat.
  • They cost more upfront but typically last up to 20 years, against roughly 12 years for a standard tank.
  • Running costs are lower since the unit only heats water when a tap is actually turned on.
  • Switching from an existing tank system usually requires a gas flow check before installation.

If you’re worried your old hot water tank won’t keep up with your household’s needs, it might be time to look at a tankless instant system. Here’s why more homeowners are making the switch.

Related → Continuous flow hot water systems explained | Why gas systems fail early

7 Reasons to Choose Tankless

1
Continuous water supply. Traditional tanks run out and need to reheat. Instantaneous systems heat on demand, so hot water doesn’t run out regardless of how many showers or loads of washing run back to back.
2
Energy savings. Storage tanks burn energy around the clock keeping water hot. An instant system only heats water when a tap is turned on.
3
Less bulk. Roughly the size of a small suitcase, compared to a large storage tank, which frees up space in smaller homes.
4
Reduced emissions. Instant gas systems generally produce lower emissions than traditional electric storage systems.
5
Durability. Storage tanks typically last around 12 years. Tankless systems are built to last up to 20 years with proper maintenance.
6
Cleaner water. Water isn’t sitting in a tank for extended periods, so it comes fresher straight from the mains.
7
No bacteria growth. No standing water means no reservoir for bacteria like Legionella to establish.

What to Consider Before Switching

Tankless systems need adequate gas flow and, in most cases, a compliant flue installation. If you’re replacing an existing tank system, your installer will need to check your current gas line can support the new unit’s demand before quoting the job.

Worth knowing: if your hot water system has come to a premature end, a tankless system is worth considering as the replacement rather than a like-for-like swap.

Ready to make the switch?
Aus Star Plumbing & Gas installs tankless and continuous flow systems across Perth’s south corridor and Peel region, including checking your existing gas line can support the new unit before any work starts. Licence PL7378, Gas Number GL011668.

Aus Star Plumbing & Gas, Licence PL7378, servicing Perth’s south corridor and Peel region including Rockingham, Baldivis, Kwinana, Mandurah, Cockburn and surrounds.

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