Time for a New Hot Water System? Choose Once, Choose Right
Hot water systems Adelaide households buy today will likely be running for the next 10 to 20 years, so the choice you make now affects your energy bills for a long time. When the old unit fails, most people just want hot water back fast. But a few minutes of planning can save you hundreds of dollars a year and make sure your new system actually meets South Australian rules.
This guide compares gas, electric, solar, heat pump and continuous flow systems in plain English. You will find out which type suits your home, what a hot water system replacement in Adelaide typically costs, which rebates you may be able to claim, and how quickly a hot water system plumber can have you back in hot showers.
If you have no hot water right now and are not sure whether you need a replacement at all, start with our guide: Hot Water System Not Working? Repair or Replace.
What Is the Difference Between Gas, Electric and Solar Hot Water Systems?
The main difference is how each system heats the water and whether it stores it. That drives what it costs to buy, what it costs to run, and how much hot water you get.
| System | How it works | Pros | Cons |
|---|---|---|---|
| Electric storage | An element heats water in an insulated tank, often overnight on off-peak power | Cheapest to buy, simple to install | Most expensive to run; restricted for many SA replacements |
| Gas storage | A gas burner heats water in a tank | Fast recovery, suits big households | Tank can run out; ongoing gas supply charge |
| Gas continuous flow | Heats water only as you use it, no tank | Endless hot water, compact, long lifespan | Needs a good gas supply and power; higher upfront than storage |
| Heat pump | Draws heat from the air, like a reverse air conditioner, into a tank | Uses about 60 to 75% less electricity than electric storage; rebates available | Higher upfront cost; makes a low hum like an air conditioner |
| Solar | Roof collectors heat water, with a gas or electric booster for cloudy days | Lowest running costs in a sunny climate like Adelaide’s | Highest upfront cost; needs suitable roof space |
| Gravity fed | A low-pressure tank in the roof space feeds hot water by gravity | Common in older Adelaide homes | Low water pressure; usually replaced with a mains pressure system |
Storage or continuous flow? A storage system heats and holds a tank of water, so it can run out if everyone showers back to back. A continuous flow system heats on demand, so it does not run out, but it can only supply so many outlets at once.
Which Hot Water System Suits Your Adelaide Home?
There is no single best system. The right one depends on four things: whether you have mains gas, whether you have rooftop solar panels, how many people live in the house, and how much you want to spend upfront versus over time.
| Your situation | Usually the best fit | Why |
|---|---|---|
| Rooftop solar panels, any household size | Heat pump | Can run on your own daytime solar power, so running costs are very low |
| Mains gas connected, 3+ people | Gas continuous flow | Endless hot water for back-to-back showers |
| Mains gas connected, tight budget | Gas storage | Lower upfront cost than continuous flow, fast recovery |
| No mains gas (common in parts of the Adelaide Hills) | Heat pump or solar | Avoids LPG bottle costs and meets SA’s low-emission rules |
| Sunny, unshaded north-facing roof, planning to stay long term | Solar with gas or electric boost | Lowest running costs over the life of the system |
| 1 to 2 people, small unit or apartment | Compact heat pump or small continuous flow | Smaller tank or on-demand heating avoids paying to heat water you never use |
| Old gravity-fed tank in the roof | Mains pressure replacement (type depends on the above) | Much better water pressure throughout the home |
Thinking of getting off gas? If you are replacing a gas system with an electric one in a home connected to mains gas, SA rules require the new electric unit to be a low-emission type such as a heat pump. Contrary to some sales claims, you do not have to disconnect your other gas appliances to make the switch.
Size matters as much as type. As a rough guide, a 1 to 3 person household often suits a 250 to 270 litre heat pump, and 3 to 5 people a 300 to 315 litre model. Your plumber should size the system to your actual hot water use, not just the old unit’s label.
SA Rules When Replacing a Hot Water System
South Australia has had water heater rules since July 2008, and they apply to replacements as well as new homes. For most houses, a new or replacement water heater must be a low-emission type, such as high-efficiency gas, solar or an electric heat pump (SA.GOV.AU).
What that means in practice:
- You often cannot swap like-for-like with a standard electric storage tank. Many homes now need a heat pump, solar or gas system instead. Some homes, such as those without a mains gas connection, may still qualify for a smaller conventional electric unit in limited cases, so check before you buy.
- Some jobs are excluded. Repairs, replacing a unit under warranty, replacing a single faulty part on a solar or heat pump system, and some gravity-fed roof-space units are not covered by the rules.
- Only a licensed plumber can install a water heater, and they must give you a Certificate of Compliance (eCOC) for the work.
- Water-efficient showerheads or flow restrictors may also be required as part of the installation.
The rules are designed to cut energy use and emissions, and the low-emission options are usually cheaper to run anyway. A good hot water system plumber will check which systems are allowed at your address before quoting, so you are never left with a non-compliant install.
How Much Does a Hot Water System Replacement Cost in Adelaide?
A hot water system replacement in Adelaide typically costs between about $735 and $5,500 installed in 2026, depending on the type and size (What’s The Damage). Electric storage sits at the bottom of that range, and heat pump and solar systems at the top.
Source: What’s The Damage, October 2026. Running costs are for a 3 to 4 person household at Brisbane energy prices; South Australia’s higher electricity prices tend to widen the gap between electric storage and efficient systems.
The cheapest to buy is rarely the cheapest to own. Over 10 years, that same guide estimates a typical heat pump comes out around $3,200 ahead of electric storage once purchase price, rebates and running costs are added up.
Extras to check on every quote:
- Removal and disposal of the old unit
- A tempering valve, required to limit bathroom hot water temperature
- New gas line, gas meter upgrade or an extra electrical circuit when changing system type
- Access costs for roof, upstairs or tight-cupboard installs
- Whether rebates have already been taken off the price
At SOS Plumbing & Gas, you get an upfront, itemised price before any work begins, so there are no surprises on the invoice.
Hot Water Rebates in South Australia
If you choose a heat pump or solar system, you can usually take several hundred dollars, and sometimes more, off the upfront price. There are three places savings can come from.Good to know:
- Only solar and heat pump models on the Clean Energy Regulator’s register earn STCs.
- You do not need to be a customer of an energy retailer to access its REPS offers.
- STC values are falling each year until the scheme winds down in 2030, so the discount shrinks over time.
- Always ask for every rebate to be shown as a separate line on your quote, so you can see the real price.
Rebate amounts and eligibility change often. Your SOS plumber can tell you what applies to your home when we quote.
How Quickly Can a Plumber Replace a Hot Water System?
A like-for-like replacement usually takes 2 to 4 hours on site, and switching to a different type of system can take up to a full day (What’s The Damage). In most cases, SOS Plumbing & Gas can have you back in hot water the same day you call.
Here is how a replacement runs from first call to first hot shower:
- Call and send a photo. A quick photo of the label on your old unit tells us the brand, size and age, and helps us bring a suitable replacement.
- Check and quote. We confirm which systems are allowed at your address under SA rules, talk through your options and give you an upfront, itemised price with any rebates shown.
- Remove the old unit. We isolate the water and energy supply, drain the tank and take the old system away.
- Install the new system. We connect water, gas or power, fit a new relief valve and tempering valve where required, and make sure the install meets current standards.
- Test and hand over. We fire it up, check temperatures and for leaks, show you how it works and explain any maintenance.
- Paperwork. You receive your Certificate of Compliance, and we handle the STC paperwork for eligible heat pump and solar systems.
Planning ahead pays. If your system is over 10 years old and showing warning signs, replacing it before it fails gives you time to compare options and claim rebates, rather than taking whatever is available in an emergency.
Which Hot Water Brand Should You Choose?
We install and service all the major brands sold in Adelaide, including Rheem, Rinnai, Dux, Bosch, AquaMAX, Chromagen, Vulcan and Thermann. Rather than chasing a brand name, compare these four things:
- Warranty on the tank and parts. Longer cylinder and parts warranties are a good sign of build quality. Check what labour is covered, and for how long.
- Local parts and service. Popular brands with parts stocked in Adelaide mean faster repairs down the track.
- Energy rating and STC eligibility. For heat pumps and solar, check the model is on the Clean Energy Regulator’s register so you get the rebate.
- The right size and type for your home. A premium brand in the wrong size will still run out of hot water.
Our plumbers will recommend a model that suits your budget and household, not the one with the biggest margin.
Hot Water System Replacement in Adelaide, Done Properly
SOS Plumbing & Gas is a small, local team founded by Adelaide plumber Lawrence. We will give you honest advice on which system suits your home, check it meets SA rules, and install it properly the first time.
- Same-day replacements across Adelaide, with a 1-hour arrival guarantee*
- Licensed plumbers and gas fitters for gas, electric, solar and heat pump systems
- Upfront, itemised pricing with rebates shown on the quote
- All major brands supplied, installed and serviced
- No callout fees,* pensioner discounts and no-interest payment plans
- Old unit removed and your compliance certificate supplied
Ready for a new hot water system? Call 1300 307 498 or request a free quote. Need a repair instead? See our hot water repairs Adelaide service.
FAQ
Do heat pumps work in Adelaide’s winter?
Yes. Adelaide’s mild winters suit heat pumps well. They work less efficiently on the coldest nights, which is why many models have a backup element and can be set to heat during the warmer part of the day.
Can I switch from gas to a heat pump?
Yes, and it is a common upgrade. You do not have to disconnect your other gas appliances to do it. The heat pump needs a power point or circuit and a suitable outdoor spot with airflow.
Is continuous flow cheaper to run than gas storage?
Usually a little, because it only heats water when you use it and has no tank losses. The bigger benefit is never running out of hot water.
Can I put my new system in a different spot?
Often, yes. Relocating a system means extra plumbing and gas or electrical work, so ask for it as a separate line on your quote.
Will my new system need a tempering valve?
Most new installations do. It mixes in cold water so bathroom taps cannot deliver scalding hot water, while the tank stays hot enough to control bacteria.