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Types Electric Hot Water Systems and how they work: Electric Storage vs Instantaneous Electric
How an electric storage hot water system works
An electric hot water system works by water being stored inside a tank which is then heated by an immersion element. The element is energised by a thermostat which will turn off the element once the desired temperature has been reached. This temperature will always be above 60 degrees for legionella purposes. Also, electric storage hot water systems have a pressure temperature relief valve which is needed for expansion as when the water heats it expands. This expansion is then relieved through this relief valve or in some parts of the country a cold water expansion valve.
How an instantaneous electric hot water system works
Rather than heating water and storing it for use later, an instantaneous hot heats water as it flows through the system. This is achieved by a slower water flow rate along with adding electricity more quickly to the water compared to a storage tank. The most common instantaneous electric hot water system is 3 phase. Though there are single phase units available. Please consider that these single phase units only work well in warmer climates in Australia as not enough electricity is able to be put into the hot water system.
Brands of Electric Hot Water Systems
Here at Same Day Hot Water Service we generally try to use Australian owned and manufactured products. Fortunately, the majority of large capacity electric storage tanks are made right here in Australia! Rinnai has a manufacturing facility in Melbourne Braeside. Rinnai still has some products manufactured in China. Rheem has a vitreous enamel factory in Sydney Rydalmere. In addition, Rheem has an Aquamax/Stainless Steel factory in Moorabbin Melbourne. Rheem also owns a manufacturing facility in Vietnam that manufactures some of their small capacity electric storage hot water heater range. Dux have their manufacturing facility south of Sydney in the suburb of Mossvale Southern Highlands of NSW. Additionally, Dux has some of their small capacity electric storage hot water heater range manufactured in factories in China.
Instantaneous electric hot water system brands include Wilson, Zip, and the most common in the market Stiebel Eltron.
Warranties and Longevity of Electric Hot Water Systems
Warranty varies based on the brand and material the tank is manufactured with. The warranties for Electric Hot Water Systems range from 7 years up to 12 years. Electric Storage Hot Water Tanks are available in both stainless steel and vitreous enamel. Note the stainless steel tank is only available in Rheem for mainstream products. Vitreous enamel electric storage tanks are protected by a sacrificial anode. For the majority of the country the sacrificial anode is usually made from magnesium. Though in some parts of Australia where there is a higher level of total dissolved solids the anode is made from aluminum. As the name “sacrificial anode” suggests, the anode sacrifices itself for the longevity of the tank.
Efficiency of Instantaneous Electric and Electric Storage Hot Water Systems
The thermal efficiency of the instantaneous electric hot water systems is approximately 25 percent more efficient than electric storage hot water systems. Though there are a couple of catches including that the water is significantly slowed down going through as it flows through the system compared to the storage tanks.
Although electric storage tanks are not quite as efficient, they are still extremely good at holding their heat. Even after a few days an electric storage hot water system will still provide a usable hot water temperature.
Across Australia there are 3 main tariffs for electricity. They include: Off peak/night time tariff; Shoulder Tariff/ Off Peak 2 ; Peak load or Continuous Power
Off peak/night time tariff heating usually heats water between approximately the hours of 11:00PM to 7:00AM. As the off peak name suggests, this electricity is made available during the off peak period when there is a surplus amount of electricity available. Depending where you live in Australia affects the cost of off peak power electricity. However, in a lot of cases the cost is significantly less and can be half the cost of regular electricity. The best electric hot water heaters suited for off peak power tariffs are large capacity electric storage tanks. This is electric storage heaters with a capacity of 250 litres, 315 litres, or 400 litres.
Shoulder tariff also known as Off Peak 2 is very similar to Off Peak One tariff. The difference is that Off Peak 2 has an additional heating cycle during the day from between approximately 10:00AM-4:00PM. In return for allowing you to heat your water during this period the electricity companies will usually charge you two thirds of your peak electricity costs. Off Peak 2 can be used for electric storage heaters with capacities of 125 litres and 160 litres. Though more commonly Off Peak 2 tariff is used for larger families when the off peak simply is not enough to keep your family in hot water.
Peak load or Continuous Power electricity is the most expensive out of the three tariff types as you are having 24 hour access to electricity. In most cases this power cycle is used for electric storage tank sizes from 25 litres to 160 litres. This tariff is especially popular in apartments and townhouses.
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- Pricing is subject to site conditions and onsite inspection.
- Note: laundry, apartment, and cupboard installations will likely require onsite quotation and may not be subject to advertised pricing due to complexity of works.
- Supply & Install prices are for like for like installations.
- Supply & Install prices include removal of old system.
- Supply & Install products purchased by credit card are subject to an additional 1% surcharge.
- Open air free parking space will need to be provided by customer at the same location as the installation. Additional charges may apply if this cannot be provided.
- Additional ($90.00 Incl GST) cost for installation of a cold water expansion valve if required.
- Hot Water Systems may require a 20% restocking fee.
- Non 50˚C preset models require a tempering valve ($185.00 inc GST) if feeding bathrooms or general hand washing areas.
- Additional ($90.00 inc GST) cost for installation of 15mm Duo Valve if required.
- Additional ($110.00 inc GST) cost for installation of 15mm Pressure Limiting Valve if required.
- Additional ($65.00 inc GST) cost for Concrete Slab or Pizza Base if required.