Choosing a hot water system affects your comfort, your energy bills and how much you’ll spend on repairs down the track. The right choice depends on your household size, how you use hot water, your energy source, available space and what you’re willing to spend upfront versus over time.
The best hot water system is the one that meets your household’s daily demand without costing more than it needs to install or run. There’s no single system that suits every home. Need hot water restored today? You’ll want fast, practical advice. Planning ahead? You’ve got more room to compare running costs and rebates first.
Before comparing models, run through this shortlist:
Working through this list before comparing brands and models saves you time and stops you paying for capacity you don’t need.
A single person and a family of four put very different demands on a hot water system. More people usually mean a larger storage tank or a higher recovery rate, especially for households with teenagers who shower back-to-back each morning.
Focus on peak usage rather than daily usage: a home with two bathrooms running showers alongside the washing machine needs a system that can keep up, not one that just averages out over 24 hours. Rental properties are also worth a second thought, since tenant usage patterns can shift.
Household storage tanks in Australia typically range from around 250 to 400 litres, with smaller households sometimes suited to 125L or 160L units. Exact sizing should still be confirmed with your installer, since fixtures and habits vary from home to home.
Storage tank systems heat and store water in an insulated tank in advance. They suit households seeking a reliable, ready-to-go buffer, though an undersized tank can run out of water during peak demand.
Continuous-flow (instantaneous) systems heat water on demand rather than storing it; they are most common in gas hot water systems. They suit households wanting a smaller footprint, since there’s no bulky tank. Size these to the number of outlets running at once, not just the number of people in the house.
Electric hot water systems are often the cheapest to buy and the simplest like-for-like replacement, popular in apartments and budget-conscious households. They tend to be the most expensive to run and generate the most greenhouse gas emissions, unless paired with an off-peak tariff or solar PV.
Gas hot water systems suit homes already connected to natural gas, are available in storage and continuous-flow models, and are typically cheaper to run than electric systems, depending on local rates. Installation depends on your gas supply and ventilation.
Solar hot water systems heat water directly using roof-mounted collectors, and can provide up to 90% of a household’s hot water needs in the right conditions. They cost more upfront but can significantly lower running costs over time, depending on roof orientation, shading, climate, and whether the unit has a booster for cloudy periods.
Heat pump hot water systems extract warmth from the ambient air rather than generating heat directly, making them among the most energy-efficient options available. Heat pump water heaters use about 30% as much energy as a conventional electric system and pair well with solar PV. The trade-off is a higher purchase cost, an outdoor unit needing airflow, some compressor noise, and reduced performance in cold climates unless you choose a model built for it.
The cheapest system to buy isn’t always the cheapest to own. An electric storage water heater looks attractive on price, but a heat pump or solar system can claw that difference back through lower running costs over five to ten years.
| Factor | Why it matters |
| Purchase price | Sets your upfront budget |
| Installation cost | Varies with plumbing, electrical or gas work and access |
| Running costs | Affects your bills for the life of the unit |
| Maintenance | Impacts long-term reliability |
| Warranty | Reduces your risk if something goes wrong |
| Rebates | Can reduce upfront cost for eligible systems |
Investors usually value reliability and simple servicing over shaving a few dollars off running costs. Emergency replacements may limit your options, but it’s worth asking whether a better system can be installed just as quickly.
Solar hot water systems and eligible heat pump systems can qualify for Small-scale Technology Certificates (STCs), which can be traded for a discount on the purchase price. Some states also run their own rebates or energy-efficiency upgrade programs in addition to the federal STC program. Eligibility and amounts shift depending on where you live and what’s currently funded, so confirm current figures with your supplier before you commit.
Check what you’re working with. Gas or LPG connection, electrical capacity, solar panels or an off-peak tariff, and whether your current unit is indoor, outdoor or roof-mounted all matter. Space is just as important, since a new system won’t always match the old one’s footprint. Heat pumps need airflow clearance, gas units need ventilation, and roof-mounted solar depends on your roof’s condition and access.
A system that performs brilliantly in Queensland won’t necessarily suit Tasmania or the high country. Solar performance depends on how much direct sun your roof gets, and heat pump performance varies by model and climate, with colder regions needing a heat pump built for those conditions. A local installer who knows your area’s water quality and typical setups is worth more than a generic guide.
| Property type | Suits | Why |
| Apartments and townhouses | Smaller electric or continuous flow systems | Limited space, sometimes strata restrictions |
| Family homes | Larger storage, heat pump, solar or gas systems | Multiple bathrooms, higher morning and evening demand |
| Investment properties | Well-supported brands with solid warranty backing | Tenants need reliable, straightforward systems |
| Renovations and new builds | Any energy source, including solar PV or fully electric | Most flexibility to reconsider setup from scratch |
Don’t choose on price alone. Warranty length, parts availability and installer familiarity all affect how much hassle you’ll deal with down the track. Same Day Hot Water Service carries all the major brands, including Rheem, Rinnai, Dux, Bosch, Vulcan, Aquamax, Quantum, Evoheat, and Stiebel Eltron, so you can compare brands and system types in one place.
| Situation | Likely direction |
| Current system worked well and failed suddenly | Consider like-for-like replacement |
| Household has grown | Review tank capacity and recovery rate |
| Energy bills are high | Compare heat pump, solar or a more efficient option |
| No gas connection | Electric, heat pump or solar may suit better |
| Planning long-term ownership | Weigh total cost over time, not just purchase price |
| Need hot water today | Ask what fast replacement options are available in your area |
Like-for-like is often the fastest, simplest path if your current system served you well and your household hasn’t changed. It’s still worth asking whether a different system could cut your running costs, particularly if you’re upgrading rather than facing an emergency.
| System type | Best suited to | Main consideration |
| Electric storage | Budget replacements, apartments, simple installs | Running costs can be higher |
| Gas storage | Homes already connected to gas | Needs gas supply and suitable location |
| Gas continuous flow | Smaller spaces, on-demand hot water | Needs sufficient gas capacity |
| Heat pump | Energy-conscious homeowners, solar PV homes | Higher upfront cost, needs outdoor space |
| Solar hot water | Sunny homes with suitable roof space | Higher upfront cost, roof suitability required |
| Instantaneous electric | Small demand or single outlet | May not suit whole-home high demand |
Talk to a specialist when your system has failed, your household keeps running out of hot water, you’re switching energy sources, installation space is tight, or you’re weighing up capacity across several bathrooms. A specialist can confirm what will actually fit and which systems genuinely suit your home before you commit.
Same Day Hot Water Service supplies and installs electric, gas, solar and heat pump hot water systems across Australia, with same-day installation available in Sydney, Melbourne, the Central Coast and Newcastle. Whether you need fast advice after a system failure or you’re comparing options ahead of a planned upgrade, our team can talk you through what suits your household, budget and property before you book anything in.
It depends on your connections and budget, but families generally need enough capacity for peak shower times across multiple bathrooms plus appliance use. Gas, heat pump, solar or a larger electric system can all work.
Sizing depends on household size, bathrooms in use, shower habits, bath use, and appliance use. Get expert sizing advice rather than a general estimate.
Heat pumps can cut running costs because they use about 30% as much energy as a conventional electric heater. Whether it’s worth it depends on your budget, outdoor space, climate and rebate eligibility.
Like-for-like is usually quickest, particularly in an emergency, but check running costs and capacity against better alternatives first, especially if your old system was undersized.
Solar can be cheaper to run once installed in sunny areas with good roof access, but costs more upfront. Electric is simpler and cheaper to install but generally costs more to run over time.
It depends on location, system type and stock availability, but Same Day Hot Water Service offers fast installation support across Sydney, Melbourne, Newcastle and the Central Coast.