Six questions that determine the right system for your household. We'll walk you through each, then quote three options.
The best hot water system in Australia depends on six things: household size, how many bathrooms run at once, which fuels you have, roof orientation, your up-front versus running-cost budget, and how long you will stay. Heat pumps and solar pay back best if you are staying five or more years, gas continuous-flow suits most homes on mains gas, and electric storage suits tight budgets or holiday homes. AHHAC sizes and quotes three options side by side.
Reviewed by the AHHAC Technical Team — licensed plumbers & hydronic engineers, NSW Lic 262528C.How we write & review
1. How many people in the household? (sizes the tank or flow rate). 2. How many bathrooms running simultaneously? (peak flow). 3. Gas, electric or both available? (rules out non-options). 4. Roof orientation and shading? (eligibility for solar). 5. Budget split between up-front and running cost? (heat pump payback or not). 6. How long will you live in the home? (longer = better case for solar/heat pump).
There is no single best hot water system in Australia, only the best one for a particular house, household and state. Rather than rank products, we start from the situation. These are the patterns we see most often, with the option we usually recommend and the households it does not suit.
Location changes the shortlist. Victoria no longer allows new gas connections for most new homes, and the ACT has stopped new gas network connections, so for a new build in Melbourne or Canberra gas is usually off the table and the real choice is heat pump or solar. In frost-prone areas, check that collectors have frost protection and that a heat pump is rated for your winter lows.
Then compare on total cost, not purchase price. We put three options side by side over a 15-year horizon, including installation, likely running costs and any rebates or STCs you are eligible for, which we check for you. The system that costs more up front is often the cheaper one over its life.
For more detail, read our guides to solar and heat pump hot water, gas hot water systems and electric hot water.
Written from on-site experience by the AHHAC Technical Team.
AHHAC's in-house design and service team — licensed plumbers and hydronic engineers (Lic 262528C) who have designed and installed 2,400+ hydronic heating, cooling and hot water systems across Australia since 1998.
Every plumbing and hot water job is assessed on site, carried out by our own licensed plumbers and gasfitters to AS/NZS 3500 (plumbing) and AS/NZS 5601 (gas), pressure-tested and documented, and backed by ongoing service. Nothing is subcontracted out.
Annual operating cost over 15-year horizon, including all rebates. A unit with $1,500 higher up-front cost that saves $400/year in running costs is dramatically cheaper over its lifespan. We'll show you the all-in comparison for three options.
Storage: 50L per person (more if you have spas, bathtubs). Continuous-flow: 16 L/min for 1 bath, 20 L/min for 2 baths, 26 L/min for 3+ baths. Account for peak simultaneous use (showers + washing machine + dishwasher).
Registered solar and heat pump water heaters qualify for Small-scale Technology Certificates (STCs), and state hot water programs (e.g. Victorian Energy Upgrades, NSW incentives) may add more. Values depend on the model, postcode and year, so we confirm them at quote and handle all paperwork.
"AHHAC delivered our 22-zone underfloor system on time, on budget and to spec. The crew were tidy, the documentation was thorough, and the commissioning was textbook."
"We've worked with AHHAC for 17 years. They've installed and serviced our hot water plant across three commercial buildings — and they pick up the phone on weekends."
"Three mobs quoted us; AHHAC's design was the only one based on a proper heat-loss calculation. The system runs beautifully — the others would've been oversized and expensive."