Their power source is clean, convenient and available at most locations.
Their purchase cost is relatively low and they require very little maintenance or servicing. They are also inexpensive to service.
They can source power from photo voltaic (PV solar) cells and run at off-peak times to greatly reduce power costs.
They come in a wide range of sizes and configurations, including storage mains pressure element type units, small to large volume on-demand and commercial fast recovery three phase storage units
Storage versus instantaneous systems
Electric hot water can use a storage (tank at mains pressure) system or an instantaneous (on demand) heating unit.
For low volume needs, such as small households with few members, an on-demand water heater can make a lot of sense.
All on-demand units require three phase power.
For larger-households, in which more than one person may want to use hot water at the same time, storage systems work better.
Storage water heaters are less expensive and less prone to mechanical problems. They also encourage thrift when showering, since there's a finite amount of hot water.
More electric hot water facts
Electric heaters cost more to run that equivalent gas heaters but this can be offset over the life of the system due to lower purchase, installation and maintenance costs.
Electric systems produce 25%-30% more greenhouse gas emission's than equivalent gas-powered units.
The Australian Standard for the delivery of hot water is 50o C (kid safe).
Electric power is measured in Kilowatts (kW).
Electric hot water systems do not come with energy efficiency star ratings.
The life expectancy of a mild steel hot water storage tank unit at 60oC for a 4 person family in Perth averages 10 years. Tank life span is affected by water quality, pressure, volume of water heated and the operating temperature. Reducing any of the last three of these variables will extend tank life span. The oldest stainless steel storage tank we've replaced was a 22 year-old Aquamax tank.