Gas hot water systems Sydney, Melbourne and Brisbane — gas storage and continuous-flow units, fast recovery, lower running cost than electric, mature technology, well-suited to most Australian homes. Authorised Rinnai, Rheem and Bosch installer.
Gas hot water remains the most popular hot-water choice in Australia for a reason. Burning gas to heat water is fast (instant warm-up), inexpensive to run (gas tariffs are around a third the price of electric resistance), and the units themselves are mature, robust and inexpensive to buy. AHHAC installs both gas storage tanks and continuous-flow (instantaneous) gas units, with full STC paperwork and certificate of compliance handled in-house.
We're an authorised Rinnai, Rheem and Bosch supplier, and we also install Vulcan, Aquamax and Dux units where required. For Australian homes with three or more occupants, we almost always recommend continuous-flow over storage — never running out of hot water, a smaller wall footprint, and typically a longer manufacturer warranty.
Continuous-flow units heat water on demand through a finned heat exchanger — there's no tank. You only burn gas when hot water is being drawn. Modern Rinnai Infinity, Rheem Continuous-Flow and Bosch HydroPower units sit around 6-star energy ratings and deliver up to 32 litres per minute (twin-bathroom homes).
Storage tanks (130 L to 360 L typical) maintain a reservoir of pre-heated water — fast first-draw and good for homes with surge demand (multiple morning showers at the same time). The downside is standby heat loss — even an insulated tank gives off ~15% of its stored heat per day, which the burner has to make up.
Our default recommendation: continuous-flow for 1–4 person homes with one or two bathrooms, storage for larger families with simultaneous showers and bathtub fills.
Continuous-flow capacity is measured in litres-per-minute at a 25 °C temperature rise (typical Australian conditions). A 26 LPM unit (Rinnai Infinity 26) handles two showers + a kitchen tap simultaneously without drop. A 32 LPM unit covers up to three bathrooms.
For storage tanks, sizing is based on the number of bathrooms and peak draw — typically 170 L for a 2-person home, 250 L for 4-person, 315 L for 5+. AHHAC sizes every install at the design stage with a 30-minute on-site flow test for retrofits.
The current Rinnai Sensei range adds a Wi-Fi gateway, recirculation modes (instant hot at the tap) and built-in flow monitoring — you can see exactly how much gas your hot water is using day to day. Rheem MetroMax II provides similar app control.
Operating cost on natural gas in Australia (2026 average tariffs): a typical 4-person home uses 12,000–18,000 MJ/year for hot water alone — roughly $500–$800 in gas. The same household on electric resistance hot water would spend $1,500–$2,200 a year. Switching from electric to gas continuous-flow typically pays back in 4–6 years.
Replacing an old electric storage tank with a gas continuous-flow system qualifies for Small-scale Technology Certificates worth $300–$600 in NSW and VIC. AHHAC handles the rebate paperwork at the install. Some state programs (VEU, NSW PDRS, REPS) also subsidise gas upgrades.
Installation requires a gas connection of adequate size and a compliant flue path. For continuous-flow units the unit is wall-mounted (typically outside or in a vented enclosure). Storage tanks are floor-mounted in a vented enclosure or external area. All AHHAC gas hot-water installs include certificate of compliance and final pressure testing.
Japanese-engineered 26 LPM continuous-flow gas unit. The dominant Australian choice — Wi-Fi-ready, 12-year heat exchanger warranty, handles two bathrooms simultaneously.
Australian-made 26 LPM continuous-flow with built-in Wi-Fi, recirculation mode, and a market-leading 6-star energy rating.
Continuous-flow gas booster paired with rooftop solar collectors — 70–80% of annual hot water from the sun, gas top-up only when needed.
Premium 360 L gas storage tank for high-demand households — vitreous enamel lined, 10-year tank warranty, fast 130 L/h recovery.
For most households, continuous-flow wins: smaller footprint, never run out of hot water, longer warranty (10–12 years), more efficient. Storage gas is only better in very large households (5+ people) or where you need a big hot water buffer for multiple simultaneous draws.
Modern condensing gas systems achieve 92–96% net efficiency by recovering heat from flue gases. We install Rheem and Rinnai units rated 5+ stars by the Australian Energy Rating Scheme.
Yes — most major models work on LPG with a simple conversion kit. We install LPG hot water across regional areas and properties not connected to natural gas mains.