Hot Water Systems FAQ’s

Every family and home is different, so understanding the how, the what and the why about hot water systems can save you money and disappointment. We’ve chosen a list of frequently asked questions to help you learn more about which system is right for you

How do I select a hot water system?

First you need to establish what kind of energy source is available to your property – Gas, Electricity or Solar, then decide which system is best for you.

What are the different types of heating methods for hot water?

Electric, Solar, Heat Pump, Water Boilers

What kind of hot water systems are there?

Storage systems or continuous flow (known as instantaneous).
Storage Systems – Water is heated and stored in an insulated tank ready for use. Most gas, electric, solar and heat pump hot water systems use a tank.

– Instant hot water heaters heat only the water required and because there is no storage tank (they are also known as tankless water heaters) so they do not experience heat/energy losses of storage systems. They operate on natural gas, LPG or electricity. Most models use gas, but electric models are available.

How much should I pay for a hot water system?

System Type  Avg. Minimum Price Avg. Maximum Price
Electric – “Storage” type $450 (25L) $1800 (400L)
Electric – “Instant” type $660 $1300
Gas – “Storage” type $850 (135L) $1500 (360L)
Gas – “Instant” type $750 $1600
Solar – Roof Mounted (electric boost) $3600 $4400
Solar – Split System (electric boost) $3900 $5000+
Solar – Split System (gas boost) $4900 $6500+
Solar – Evacuated tube $4000 $5500
Heat Pump $3300 (160L) $4000 (315L)

How do I determine what size water heater to buy?

This depends on how many people live in your home, how much hot water you use, and when you use it. A storage heater that is too small will continually run out of hot water, while one that is too large will be more expensive to run because it will maintain the water temperature even when it is not being used. It is important to select the right hot water system for your needs. Australian Hot Water will help you choose the right-sized system for your household.
Water heater size chart

How do I choose an energy efficient hot water system?

This will depend on your energy source, household size, budget, and preference for instantaneous or storage systems. If you’re connected to mains gas and your house gets a fair amount of sunlight, the most ideal system could be a solar storage hot water system with gas boosters. If your property doesn’t get much sunlight, the next best thing is an instantaneous gas system.
There is never one model that suits all households when it comes to cutting your energy bill, but electric hot water systems have high emissions and are often considered to be the most expensive option.

How do the different systems work and what are the pros and cons?

Electric water heaters
How it works
Electric storage hot water systems heat water with an element in the bottom of the unit and store it in an insulated tank ready for use. Continuous systems are similar, but instead the element is coiled around the pipes to quickly heat the water inside.
Electric hot water systems have quite low up-front costs and are a reliable way to keep your water warm. Some electric hot water systems can also be pre-set to do the majority of its heating during off-peak periods to help minimise your energy bill.
Electrical hot water systems are almost always the most expensive long-term solution. They also have high greenhouse gas emissions and are generally advised against.
Gas water heaters
How it works
Storage systems use a gas burner to continuously heat and maintain water in a tank. Continuous flow systems or tankless gas water heaters use a burner which ignites only when the water is needed.
Gas hot water systems produce less greenhouse gas emissions than electric systems. Additionally, depending on your location, gas systems are usually considered to have lower usage rates compared to electricity, making them the most cost-effective option long term.
Gas hot water systems are only really viable if you’re connected to mains gas, as using gas bottles is more expensive and you could end up running out of hot water. Gas hot water systems must also be located outside, or have an exhaust vent if they are located inside.
Solar water heaters
How it works
Solar hot water systems are storage units which generate heat from the sun using panels mounted on the roof of the property. This heat is used to warm and maintain the water in your tank.
Solar hot water systems are able to reduce your hot water systems energy consumption by up to 90%, significantly saving on your power bill. Solar hot water systems are also the most environmentally friendly option and energy efficient.
Solar hot water systems have the highest up-front costs – anywhere from $2,000 to $7,000 after rebates depending on the system size, and excluding installation costs. Some solar hot water systems can be unreliable on overcast days, though most models will kick-over to gas or electric back-up heating if the water isn’t hot enough.
Heat pump water heaters
How it works
Heat pumps have a fan that draws warm air into the system, which is transferred to the water storage tank. Like a reverse fridge. Rather than pumping out hot air to keep your fridge cool, it pumps hot air in to heat the system up. Heat pumps circulate water from the storage tank through a compressor using Co2 refrigerant and the hot air drawn in from the outside temperature to heat the water and send it back to the storage tank.
Heat pumps are one of the most energy efficient hot water solutions. While they need electricity to run, they are roughly three times more efficient than traditional electric water heaters.
Heat pumps are only suitable in warm environments. While some heat pumps do come with boosters, if the climate isn’t suitable, there is little benefit in spending the extra money on a heap pump.

How much does it cost to install a hot water system?

If you’re replacing an existing hot water system with the same type in the same position, installation costs are relatively low, in the range of $220 to $660. If additional valves are required, or if plumbing or electrical systems require upgrades, costs will be higher.
If you need to reposition your hot water system to a different site on the property, installation costs could be another $1000 to $2000 depending on the plumbing and electrical work required.
Changing energy type, for example, switching from electric to gas, will require additional work and cost in the realm of $1500 to $3000. If you are upgrading the size of your system, additional plumbing and electrical work may be required.

How long do hot water systems last?

Check out the article in the following link to get an idea of how long hot water systems last.

Are gas hot water systems energy efficient?

Energy efficiency depends on daily water usage. For example, tankless heaters that use 155L or fewer can be 24-34% more energy-efficient than regular water heaters. Whereas tankless heaters that used greater than 325L daily can be 8-14% more energy-efficient.

How much energy does an electric hot water system use?

The average thermal dispersion for water heaters is between 1 and 2 kWh/24 hr.

Can I switch to a gas hot water if I don’t have the piping? 

If you have gas piping in your street, your home can be connected to natural gas. If gas is not available, you can install a propane (also known as LPG) gas water heater, which can be run from refillable gas bottles.

Does a Hot Water System need servicing? 

Yes and regularly. It is heating water, expanding and contracting, building and releasing pressure day in and day out. Yet it is often the most neglected and overlooked appliance in a houses. Most modern water heaters have a life expectancy of between 7-10 years.  Check your manufacturers and trade recommendations to see if your unit needs to be serviced every 5 years, annual or bi-annual maintenance. 

Still have questions? Speak to a hot water plumber near you to get professional advice specific to your requirements.