Comparison of Hot Water Systems – electric vs gas water heaters

May 15th, 2014

Appliance Talk Hot Water Systems

Ever wondered what kind of hot water system would best suit your home’s needs?

water heater comparison

Here’s a quick guide that compares different hot water systems, including electric and gas-powered heaters in Storage and Continuous Flow designs, to help you make an informed decision.

Electric water heaters

Rinnai Electric Hot Water System EHF50S36Rinnai Electric Hot Water System EHF50S36

Most electric hot water systems sold at Appliances Online are Storage type water heaters, consisting of a traditional cylindrical tank that maintains a supply of heated water for the home.

Depending on their size (a tank with a capacity of approximately 50L per person should suit most households), these tanks can be installed indoors or outdoors, and are generally cheaper to buy and install upfront than gas hot water systems.  Plus, they only require connection to water and power to function.

Rinnai Electric Hot Water System EHF250S36Rinnai Electric Hot Water System EHF250S36

However, these storage systems are not always the most efficient choice of water heater.  Although insulated, water storage tanks inevitably lose heat, so a significant amount of energy – and therefore money – must be used to sustain the right temperature over time, even when using off-peak electricity.

Storage systems can also run out of hot water – often an issue for members of a large family who are late in line for the shower!

Heat Pump water heaters

These hot water systems are a bit unusual in the way that they heat their water.  Rather than warming their water with an electric element, they do so by extracting solar energy from surrounding air (much like a reverse cycle air conditioner), resulting in less energy use overall – approximately a quarter that of a standard electrical hot water system of similar size.

Atlantic Heat Pump Solar Hot Water System ODYSSEO2Atlantic Heat Pump Solar Hot Water System ODYSSEO2

Heat Pump water heaters have a reputation for a being noisy, to the point where some local councils don’t allow them to operate at night.  However, Atlantic’s Odysseo 2 (pictured above) has been specifically designed to operate quietly, and is in fact recommended for indoor installation.

Due to their more complex technology, heat pumps are one of the pricier heating options to buy upfront; however their energy savings over time should help to justify the initial expense.

Gas hot water systems

Gas hot water systems are often Continuous Flow models – small wall-mounted tankless units that instantaneously heat water only as you use it. When the hot tap is turned on, cold water is fed through a heat exchanger, raising the temperature of the water that is sent onwards through the pipe.

This ensures that your household won’t run out of water, so you should never be surprised by a suddenly cold shower…

Rinnai Natural Gas Continuous Flow Hot Water System INF32EN60Rinnai Natural Gas Continuous Flow Hot Water System INF32EN60

You can calculate the appropriate size of continuous flow hot water system for your household based on its Water Flow specification.  16L/min is enough for a two-person household, and models are available at Appliances Online with a flow of up to 32L/min – according to Sustainability Victoria, this should be enough to suit a large household with at least 3 outlets in use at once.

Rheem Natural Gas Continuous Flow Hot Water System 874E16NFRheem Natural Gas Continuous Flow Hot Water System 874E16NF

It does take a short amount of time for the heat exchanger in one of these units to warm up your water, meaning you could potentially waste one or two litres of cold water each time you turn on your tap and wait for the hot stuff.  You can minimise this water wastage by only turning the tap on at a low rate while the water is warming, or by installing a water recirculation system into new or existing plumbing – at the press of a button, the cold water is pumped back to the heater until the water warms up.

Gas hot water systems are generally more expensive upfront than similar electric systems, though the gas models do tend to have cheaper running costs in the long term.

Natural gas or LPG connection?

Different models of gas hot water system are designed to suit either your home’s built-in natural gas supply, or an LPG tank like you’d use on the barbeque.

If you opt for a natural gas hot water system, you’ll require relatively large diameter gas piping to cope with a continuous flow system’s fuel requirements.

Rinnai Natural Gas Continuous Flow Hot Water System INF26ANPLUSRinnai Natural Gas Continuous Flow Hot Water System INF26ANPLUS

Ideally, the system should be positioned as close as possible to outlets that need the most amount of hot water, such as the shower or kitchen sink. The further away, the more heat dissipates through the pipes and the longer the outlet takes to get the water.

Prior to your install, you should get a quote from a gas technician to see if any modifications need to be made to your gas supply.  Installing a gas hot water system is typically more expensive than installing a similar electric model, but should cost less in the long run through savings on your energy bills.

Rheem LPG Continuous Flow Hot Water System 874627PFRheem LPG Continuous Flow Hot Water System 874627PF

LPG hot water systems are a great alternative for households lacking a convenient natural gas connection, although they should also be set up by a licensed gas plumber for safety’s sake, and of course you will also need to periodically refill the LPG canister.

What’s best for you?

If you need any more assistance figuring out which hot water system models are best suited to your needs, contact the experts in the Appliances Online team – we’re available 24/7, 365 days a year, through email, live chat, and on the phone at 1300 000 500.

Mark joined Appliances Online in November 2011 and has since learned more than he ever expected to know about appliances. He enjoys looking for new and unusual ways for to solve everyday problems using typical household appliances. When he’s not toiling at the desks of Appliances Online and Big Brown Box, he tries to find time to write the next big bestseller and draw satirical cartoons, but is too easily distracted by TV, music and video games. Mark’s favourite appliance is the Dyson Groom Tool, as he loves the concept of vacuuming your dog. Google+

Leave a Reply

Your email address will not be published. Required fields are marked *