There are many energy sources you can use!
These include electricity, gas (LPG and Natural) and renewable energy sources such as the sun, the air, wood and even pellet type fuel sources. What's more, you can combine energy sources for incredibly efficient and environmentally friendly water heating solutions.
All in all, there are numerous ways to heat your hot water and the right option for you will depend on many things, including your preferred energy source, whether you have a low or mains pressure water source, the number of people, showers and baths in your home, your climate zone and even the actual flow rate of your showers. i.e. the litres per minute.
1. Low Pressure Storage Information Courtesy of Rheem NZ Ltd - The Truth about Hot Water in you Home (2010)
2. Mains Pressue Storage
3. Heat Pump Water Heater
5. Continuous Flow
4. Gas Condensing Boilers.