Best Hot Water Systems: Reviews & Prices
Need a new hot water system?
Want to find the best hot water systems?
Concerned that what your plumber recommends may not be the best choice for you or your home?
What size hot water service do I need?
Want to find the best price?
We review hot water system types and prices, comparing the pros and cons of the various alternatives, to help you make an informed decision.
Picking the Best Hot Water System for You
There are four key decisions involved in picking a new hot water system:
1. Hot water systems type
2. The energy source that powers it
3. Hot water service size you need
4. Hot water system price you pay
In turn, these decisions will affect the upfront cost of purchase and installation and the ongoing running costs.
Given that hot water often consumes around 25% of a home’s energy budget, you really want to get this right.
Compare Hot Water Systems Prices
Compare prices for all the major brands of gas hot water systems including Rinnai, Bosch, Kelvinator, Rheem, Dux and AquaMAX.
Click on your category of interest to compare prices:
Hot Water Service – A Review of Your Choices
Electric Storage Hot Water Systems
Also known as hot water tanks or cylinders, these have been the most common hot water system in Australia for decades.
Gas Storage Hot Water Systems
Appearing similar to an electric tank or cylinder, the primary difference is that the electric heat element is replaced with a gas burner.
Gas storage hot water units are energy efficient, particularly if you choose one of the new 4 or 5-Star models, and they have much lower greenhouse gas emissions.
Also, there are no time-of-day tariff issues with gas.
This means that gas storage units do not need to be as large, as the gas burner can operate whenever required.
Solar Hot Water System
A solar hot water system can have some of the lowest running costs and greenhouse gas emissions, but they are typically the most expensive to install, with installed cost as much as 4X that of a storage unit, even with rebates.
Solar hot water system boosters can be electric, natural gas or LPG.
Solar hot water system option may take a number of days to install.
Heat Pump Hot Water
Heat pump hot water systems heat your water by extracting heat from the ambient outside air, in the same way that a reverse cycle air conditioner would heat a room.
The heat pump hot water is kept in a tank, similar to storage systems.
Heat pump hot water can be quite efficient and have low greenhouse gas emissions but, once again, the upfront costs are substantial.
Heat pump hot water units can be very noisy.
Gas Continuous Flow Hot Water Systems
On Demand Gas Water Heater Reviews
Sometimes referred to as ‘instantaneous’ or ‘tankless’, these units heat the water as you need it – on demand.
Instantaneous Electric Hot Water Systems
Instantaneous electric hot water systems are also available.
However, they are not very common.
As they are used during the day, you pay the full electricity tariff, as opposed to off-peak electric storage units.
This higher cost of operation is the main reason for the rarity of instantaneous electric hot water systems.
How a Tankless Water Heater Works
• Cold water flows into the water heater when a hot water tap is opened inside your home.
• The water flow is detected by a sensor that ignites the gas burner, to heat the water in the heat exchanger.
• The water typically follows a serpentine pattern through the heat exchanger, absorbing as much heat as possible.
• An electronic control unit modulates the gas burner to maintain a set water temperature.
See all the details on:
Combustion Efficiency & Star Ratings
Star ratings encapsulate both a start-up heat up factor for each appliance and combustion efficiency.
As a result, combustion efficiency for each star rating can vary a bit.
However, if we look at combustion efficiency in isolation, it does make it a bit easier to understand what it all means.
The following are all approximate but will give you a good idea what to expect based on what star rating you choose:
4 Star = 73%
5 Star = 80%
6 Star = 87%
7 Star = 94%
Size and Aesthetics
Storage tank hot water heaters are big, especially the electric off-peak models.
Even when installed outdoors, the size can get in the way, particularly with today’s smaller lot sizes.
Having this large object next to your house also does nothing for the appearance of your home.
At about the size of a small suitcase, tankless water heaters are much smaller than a traditional storage tank heater.
Mounted flush against the wall, the smaller tankless units take up less space and are also more aesthetically pleasing, as they don’t dominate the exterior appearance of your home.
Health & Safety
With storage tank water heaters, there is the potential for bacteria growth within the tank.
The World Health Organisation -- WHO -- recommends that stored hot water be kept at a minimum of 60°C.
Unless a minimum of 60°C is maintained, hot water tanks can be a breeding ground for Legionnaires’ disease, or Legionellosis, that is caused by a bacterium, Legionella pneumophila.
It is a respiratory disease that can cause severe pneumonia and is sometimes fatal.
However, Canadian studies have shown, even when the thermostat is set at 60°C, a high percentage -- approximately 40% -- of electric water heaters remain contaminated.
This is because of the lower temperature, of about 30°C to 40°C, at the bottom of the tank.
With tankless systems, the prevention of bacterial growth is not an issue, as there is no stored water in which bacteria can breed.
Tankless systems can also be set at 50ºC, so the risk of scalding is greatly reduced without the need of a tempering valve.
What Size Hot Water System Do I Need?
Don't Calculate by Number of People or Bathrooms
The sizing information available is very confusing because manufacturers, and others, are trying to provide a simplified answer to a complicated question.
Some suggest that you calculate by the number of bathrooms in your home while others say to go by the number of people in your family.
Also, in many cases, their recommendations are based on the worst case scenarios, assuming higher consumption than your actual water use.
Buying Too Large Wastes Money
The result is that many people end up buying a larger system than they actually need.
This costs them extra money when they buy the hot water system and will increase the ongoing operating costs, in many instances.
Factors to Really Consider
Simultaneous use is one of the fundamental determining factors.
The number of people in your home combined with how and when they use hot water is the key.
Do they all take showers at the same general time of day?
Do they take showers simultaneously in different bathrooms?
Do the showers have WELS 3 Star Rated Showerheads (maximum 9L/Min) or standard 18 to 25L/Min showerheads?
Do some prefer baths, which use more hot water? Is the bath or spa oversized, requiring even more hot water?
Do you run the washing machine, using hot or warm water, while people are showering?
Is your dishwasher connected to the cold or hot water? If hot, do you use it while hot water is being used elsewhere?
Showers Are the Key
Showers use the most hot water in a home. People generally shower for 5 to 10 minutes.
Assuming you have a 3 Star shower head and you mix in some cold water with the hot, the typical hot water consumption would probably be in the 7 litres per minute range.
If you also assume an 8 minute shower, you will consume about 56 litres of hot water per shower or a family of four would consume 224 litres.
The use of WELS (Water Efficiency Labelling and Standards) 3 star rated showerheads is an important factor in saving water and energy whilst reducing the size and cost of the hot water system required.
Hot Water Tank Example
In the above example, if all four people take their showers in the morning, you would only need a storage hot water system with 224 litre first hour capacity, regardless of how many take showers at exactly the same time.
This all presumes that you are not using any other hot water devices at the time.
The use of additional hot water, after the shower period, would depend on the hot water system’s recovery time required to achieve full temperature.
So, with a larger family or house guests, a bit of scheduling may be required to avoid the need for a larger unit.
Off Peak Electric Issues
Off peak electric storage units are a completely different story.
Inasmuch as they only heat water at night, they need to be quite large to make sure you don’t run out of water during the day.
So, some of the electric savings is offset by the fact that you need to heat a larger tank.
The bigger tank would also cost more to purchase.
Tankless Hot Water Example
For a tankless continuous flow unit, it would depend on how many showers are being used simultaneously.
Using the example above, if it’s two showers, then you only need a unit with a minimum flow rate of 14L/min.
If you have 3 people showering at exactly the same time, you would need a minimum 21L/min.
This does assume that you are not using other hot water devices simultaneously.
Recovery time is not an issue with continuous flow units, so even a large family with guests would not run out of hot water.
Comments, questions or feedback?
The information in this article is derived from various sources and is believed to be correct at the time of publication. However, the information may not be error free and may not be applicable in all circumstances.