Hot Water Decisions Guide

Hot Water Decisions Guide

Hot Water System Decision Guide

Your hot water unit is the engine room of your home. It helps to ensure your bathroom, kitchen and laundry can perform well every day.

From the invigorating morning shower to the heavy-duty clothes wash, you need a hot water unit that can effectively meet the needs of your family.

Recently, rising energy costs and an increased emphasis on sustainability, have made choosing an efficient hot water unit even more important. That’s why we’ve put together this handy guide. It’s designed to help you select the perfect hot water unit for your needs.

iSpecialise can also provide you with valuable advice when deciding which hot water system is ideal for you.

Did you know?

About 25% of homes’ energy is used to heat hot water

Gas Units

Natural Gas hot water systems are generally cheaper to run than electric. If you are in an area which does not have natural gas available you could consider LPG. There are options for gas systems to be installed inside, however, they do require fluing.

Solar Gas Boosted


  • Utilises free energy from the sun
  • Reduced monthly gas bills
  • Government incentives
  • Uses a continuous flow unit for a backup booster, which means you will never run out of hot water


  • High installation cost
  • Tank takes up more space than continuous flow units
  • Less efficient in winter
  • Panels have to be installed on a north-facing roof to maximise the efficiency of the sun

Continuous Flow


  • Save space with small footprint mounted on your wall
  • They heat water as you need it, so you will never run out of hot water
  • Controllers can be installed to accurately deliver water temperature


  • You may need to upgrade your gas line which can add to upfront costs
  • Small amount of water is wasted in the initial delivery
  • Takes longer to deliver hot water than a storage heater

Gas Storage


  • Upfront purchase costs are usually lower than other types of hot water units
  • Lower installation costs as there is usually no gas mainline upgrades required
  • 5 Star energy-efficient models also available


  • Tank size takes up space
  • Heat loss from the tank, whether the water is being used or not
  • Not as energy-efficient as a solar or continuous flow unit

Electric Units

Electric hot water units are generally more expensive to run than natural gas units. The cost of running them can be reduced by setting the unit on an off-peak tariff or taking advantage of a free energy source like the sun. Unless the unit is running off a renewable energy source, it is likely to emit more greenhouse gas emissions versus other units

Solar Electric Boosted


  • Utilises free energy from the sun
  • Reduced monthly electric bills
  • Great for climates that receive a lot of sunshine
  • Government incentives
  • Boosting element


  • High upfront cost for equipment and installation
  • Less efficient in winter
  • Panels have to be installed on a north-facing roof to maximise the efficiency of the sun

Heat Pump


  • Can be connected to extended off-peak tariffs
  • Ease of installation as a heat pump uses the similar connections as an electric hot water system and similar footprint
  • Takes heat from ambient air to. heat water
  • Environmentally friendly


  • Can be. noisy when operating
  • Suited to warmer climates

Electric Storage


  • Same footprint when replacing a like for like unit, saving money on replacement cost
  • Most affordable unit to purchase
  • Lower tariffs are often available, which will heat water during off-peak times


  • Rates as the highest when it. comes to Co2 emissions
  • When installed on an off-peak tariff, high chance of running out of hot water during heavy load days. Water will not be reheated until overnight


  1. For SOLAR SYSYEMS, collectors should face true north and need to be inclined correctly to catch the most sunlight.
  2. CONTROLLERS can be installed to accurately deliver hot water at your desired temperature.
  3. When buying a GAS STORAGE HEATER, choose a system with a 5-star energy rating. These systems provide maximum efficiency.
  4. When you install a SOLAR hot water unit, you may be eligible to receive assistance with your purchase and installation costs via government incentives.
  5. HEAT PUMPS work at their highest efficiencies in warmer climates. Although some also have an electric booster as back up to supply hot water.

It is important to understand which electricity tariff your hot water unit is connected to. Check with your energy supplier to learn more.

OFF-PEAK  – Water is only heated at night, cheaper to run, larger size capacity is required so hot water does not run out during the day.

DOMESTIC / CONTINUOUS – Water is heated throughout the day and night as required, more expensive to run, a smaller unit can be selected as hot water can be continually heated throughout the day

If you need hot water system repairs, replacements, upgrades or general advice contact the experts at iSpecialise today.

Hot water systems we recommend are Rheem/Vulcan, Aquamax, Rinnai, Therman, Bosch

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