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Gas vs electric instant hot water systems

Instant hot water systems offer a compact, often energy efficient water heating option. Once you’ve decided instant, also called continuous flow or instantaneous, is the way you need to choose between either a gas (natural gas or LPG) and electric models.

Instant electric hot water systems only make up around 3% of water heaters used in Australia with instant gas a much more popular 21%.

Electric instant hot water units are becoming an increasingly popular substitute for homes and businesses with more models from reputable brands, such as Stiebel Eltron, coming out each year. Gas instant hot water heaters have been around for many years and have been proven to be an energy efficient alternative to traditional storage models.


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Running costs

Both gas and electric instant hot water systems offer significantly lower running costs when compared with traditional gas or electric storage tank models. Although instant systems can be more expensive to at the initial purchase stage, the lower operating costs more than compensate over the years.

For smaller applications or those with minimal hot water demands electric instant annual energy costs present significant savings compared with storage electric models. $395 instant electric per year - storage electric $555.

For higher demand applications, such as those in a 4 person household, natural gas is where the big savings are found. $970 electric vs $420 natural gas or $660 LPG.

Instant electric hot water

The yearly costs to run an electric instant for a home with 4 people is around $970, compared with $1115 for an electric storage HWS on peak tariff. Instant electric is a better option for smaller homes with one or two residents, $585 instant vs $740 storage peak.

Pros and cons of instant electric hot water

  • Both single phase 240V and 3 phase options available - units designed to supply hot water for several taps or homes with several units will typically require high power input.
  • Easy installation.
  • No ventilation requirement like gas water heaters.
  • Can be fitted in a cabinet or close to the tap or sink which means almost instant hot water when you turn on the tap, no lag.
  • Can be used in conjunction with a solar hot water system as a booster without needing a secondary power supply.
  • Quiet operation.
  • Some brands, such as Zip hot water, are designed to supply a single tap or outlet.
  • Ideal for supplying hot water to an isolated sink or shower, reducing gas pipe infrastructure needs.

Instant gas hot water

Instant gas hot water systems are a money-saving option for a huge variety of water heating needs. Your home could save $750 over the year on running costs by converting from storage electric to natural gas instant. ($365 natural gas instant - storage electric $1115 per year)

  • Up to 75% fewer greenhouse gasses produced by a gas continuous unit compared with a storage electric unit.
  • Space saving installation - taking up only a small wall area, freeing up valuable garden or cupboard space.
  • Can handle higher flow rates than electric options.
  • Need to be flued to get rid of moisture and other potentially dangerous by-products such as carbon monoxide.
  • Can be banked for higher demand hot water applications. Or multiple units installed throughout the building or home.
  • Often last twice as long as storage alternatives with fewer maintenance requirements.

Both systems have their pros and cons, applications with hot water demands on the lower end of the scale or restricted installation options, such as a studio apartment or an office kitchen, could be ideal for an electric storage hot water heater. Larger applications, such as those needed for a busy household, could be more suited to a gas powered continuous flow hot water system.

Speak to your local Sydney hot water specialists for expert advice on the best hot water solution for your home or business at Pure Plumbing Professionals today. Give us a call on 9191 7374 or complete our online hot water booking form.

Please Note - running costs quoted are to be used as a guide only.

Ref - http://energyrating.gov.au/products/water-heaters


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