Gas Hot Water Systems: Pros, Cons and Running Costs

Hot water accounts for a meaningful chunk of most household energy bills, and the type of system you run has a real impact on what that bill looks like every quarter. Gas remains one of the most popular choices for Adelaide homes, but it is not the automatic best option for every household anymore.

Below is an honest look at what gas hot water actually costs to run, where it genuinely outperforms the alternatives, and where it falls short.

How Gas Hot Water Systems Work

There are two main types worth knowing about before comparing costs.

1. Storage gas systems heat and hold water in an insulated tank, ready to use on demand, similar to how an electric storage system works but heated by a gas burner instead of an element.
2. Continuous flow (instant) gas systems have no tank at all. Water is heated as it passes through the unit on its way to the tap, which means there is technically no limit to how much hot water you can use, provided the flow rate stays within the unit’s capacity.

Continuous flow has become the more common choice in newer Adelaide installations. Why gas instant hot water systems suit modern homes covers the practical reasons behind that shift in more detail.

The Case For Gas Hot Water

• Fast, reliable heating: Gas heats water quickly, and a continuous flow system never runs out, which matters for larger families running showers back to back or filling a bath while the dishwasher is going.
• Lower running cost than electric storage: Gas is generally cheaper to run than a standard electric storage system, particularly for households with high hot water demand, since gas heats water more efficiently per unit of energy used.
• Works during a power outage: Most gas systems, particularly storage models, continue to function during an electricity outage since the heating element runs on gas rather than mains power. This is a genuine practical advantage during Adelaide storm season.
• Compact options available: A continuous flow unit mounted on an external wall takes up very little space compared to a large storage tank, which matters in homes with limited yard or garage space.

The Case Against Gas Hot Water

• Rising gas prices: South Australian gas prices have climbed steadily, and that trend shows no sign of reversing. The cost advantage gas once held over electricity has narrowed considerably in recent years, particularly for households with solar.
• Ongoing supply charges: Gas comes with a fixed daily supply charge regardless of how much you use, on top of usage costs. For a household using gas only for hot water and nothing else, that fixed charge is a meaningful chunk of the overall cost.
• Not compatible with solar generation: Unlike an electric or heat pump system, a gas hot water system cannot be powered by your rooftop solar. If you already have solar panels generating free electricity during the day, that generation cannot offset your hot water costs at all under a gas system.
• Requires a licensed gas fitter for any work: All gas appliance installation, repair, and servicing must be carried out by a licensed gas fitter in South Australia. This is not unique to gas hot water, but it does mean ongoing maintenance always involves a professional callout.
• Carbon monoxide risk if poorly maintained: A gas hot water system that is not serviced regularly or is improperly installed can develop a carbon monoxide leak. Carbon monoxide safety and how to detect it is worth reading regardless of which gas appliances you run in your home.

Running Costs: What to Actually Expect

Exact costs vary by household size, usage habits, and current gas pricing, but here is a general breakdown for a typical Adelaide household.

• Storage gas system, family of four: typically the most economical gas option for moderate hot water use, though standby heat loss from the tank adds a small ongoing cost
• Continuous flow gas system, family of four: slightly lower running cost than storage gas since there is no tank to keep hot between uses, but higher upfront purchase and installation cost
• Comparable electric storage system: usually higher running cost than either gas option unless run on a cheap off-peak tariff
• Heat pump hot water system: often the cheapest to run of all options, particularly for households with rooftop solar, since it uses a small amount of electricity to extract heat from the air rather than generating heat directly

That last point is worth sitting with. If you have solar panels or are considering installing them, a heat pump hot water system frequently works out cheaper to run than gas over the system’s lifetime, even though gas still wins on raw heating speed.

Want a clear comparison for your specific household? Call the Sharpe team on 8262 5000 or book online through the Easy Book system for advice from a licensed Adelaide technician.

Installation and Replacement Considerations

If your home already has a gas connection and an existing gas hot water system, replacing like for like is usually the most straightforward and cost-effective path. Sharpe’s gas hot water system installation covers both storage and continuous flow options across Adelaide.

If your existing system is failing and you are weighing up whether to repair or replace, age is the biggest factor. Storage systems typically last 8 to 12 years, and once a system passes that mark, repair costs start to compete with the cost of a full replacement. Speedy hot water replacement before a silent flood becomes a real one covers the warning signs that indicate a tank is on the way out rather than just due for a minor repair.

If you are switching from electric to gas, or relocating an existing system, the job involves running a gas line and may require additional gas fitting work depending on your home’s existing setup. A licensed technician needs to assess this before quoting.

Maintenance: What Gas Systems Need

Gas hot water systems are not maintenance-free, and skipping servicing is a false economy.

• Annual safety check: A yearly check verifies the burner is combusting properly, checks for any signs of corrosion or leaks, and confirms the flue is venting correctly. Sharpe’s hot water safety check and test covers exactly this.
• Sacrificial anode check (storage systems only): The anode inside a storage tank corrodes over time to protect the tank itself from rusting through. Once the anode is fully corroded, the tank starts deteriorating instead, shortening its lifespan significantly.
• Watch for warning signs: Reduced hot water pressure, rusty or discoloured water, unusual noises from the tank, or a pilot light that will not stay lit are all signals that a system needs professional attention rather than waiting for the next scheduled service.

If your system is showing any of these signs now, do not wait. Hot water repair services across Adelaide are available for exactly this kind of issue, and catching a fault early is almost always cheaper than dealing with a full tank failure later.

Get the Right Hot Water System for Your Adelaide Home

There is no single correct answer between gas, electric, and heat pump hot water. The right choice depends on your household size, whether you have solar, and what your existing setup already supports.

Sharpe Trade Services has installed and serviced hot water systems across Adelaide for 45 years, with in-house licensed gas fitters and electricians, $20 million in insurance cover, and a 10-year workmanship warranty.

Book online through Sharpe’s Easy Book system or call the team on 8262 5000.

Sharpe Trade Services. Trusted, licensed, and experienced across Adelaide.