The amount of kWh electric hot water systems use depend on the size of the system, the temperature setting, and how often the water is used.

Typically, a hot water system will use between 2 and 4 kWh per day. Every water heater comes with an energy rating label to give you a better understanding of the energy consumption. If you are looking to save energy and money on your hot water bill, be sure to choose a new hot water system with a low BTU input. You can compare the energy efficiency of different models before buying to ensure you're purchasing an efficient unit that's right for your household needs. A gas hot water heater is useful in our homes for many reasons. You can heat water to use it for bathing, cleaning, space heating and for many other reasons. When buying heat pump water heaters, you need to keep in mind the energy consumption so that you don't get a shock looking at your monthly energy bill.

What is the lowest kWh hot water system?

Hot water systems vary in energy efficiency. A low Btu input system generally uses between 2 and 4 kWh per day, while a high BTU input hot water system can use as much as 7 or 8 kWh per day.

What does BTU mean?

BTU stands for British thermal unit, a standard of measurement used to describe the rate of heater energy production or transfer. A low BTU input hot water system uses less electricity and produces more efficient results than a high Btu input system.

How do you calculate kWh on a hot water system?

The amount of kWh a hot water system will use depends on the water tank size of the system, the temperature setting, and how often the water is used. For example, a 125-litre tank at 55 degrees Celsius that's used twice a day will use about 3 kWh per day.

Energy factors

To calculate the annual running costs of different types of water heaters, you also need to consider the energy factor of that water heater. Energy factor or EF is used to determine the efficiency of a water heater. To calculate the EF, you need to take the amount of energy your electric heater is put to use and divide it by the energy required to power that heater. Calculating the EF of your water heaters will allow you to get a good idea of how long should you use them so that your electric bill remains within your budget.

How much electricity does a heat pump hot water system use?

A heat pump hot water system uses electricity only to power its heater pump. It does not use any energy to heat the water, because it relies on the outside air, which is free, instead of the electricity used by conventional solar hot water systems for this purpose.

Heat pumps work most efficiently when they are operating at around 20 degrees Celsius. Therefore if it is cold where you live and your house is well insulated, your heat pump will be able to use less electrical energy than a heat pump in a warm climate such as Queensland's Gold Coast or Cairns. However, even in cold climates such as Canberra, Tasmania and central NSW, you can expect up to 80% efficiency so you should still save money every year compared with what you would spend using an electric hot water system.

The electrical energy usage of a heat pump hot water system is about the same as that of a refrigerator. So if you have a big fridge, it will use about the same amount of electricity as a heat pump hot water system.

If you are replacing an old electric hot water system with a heat pump, your existing wiring should be able to handle the extra load. You may need to install an outdoor switch to turn your heat pump off when you are not using it.

But even if you don't have a switch, the system will only use power when it is running and it will stop heating the water when it reaches the set temperature so you will still save money on your energy bill.

What types of hot water systems can I get?

There are two main types of hot water systems, electric storage and gas storage. There is also a new type of system which is called a heat pump.

Electric storage systems

These systems use electricity to heat the water in a tank. The water is heated by an element that is either turned on all the time or turned on when you need hot water.

Electric hot water systems are the most common type of hot water systems in Australia. This is because for an electric hot water heater, you don't need to install a separate connection.

Plus, technology has become so advanced that you can now install a mini electric water heating system in your showerhead and bathe without worrying about electric shocks. You can even buy a washing machine these days that has its own mini electric water heater to clean your clothes better than before.

Gas storage systems

These systems use natural gas or LP gas to heat the water in a tank. The gas is turned on all the time and heats the water in the tank. Gas storage systems are not as common as electric storage systems, but they are becoming more popular because of the high cost of electricity.

A gas hot water system can have an EF of 0.5 to 0.7. It is true that electric water heating systems are far more efficient, but natural gas prices are lower compared to electricity these days, so you can save some money on your electricity bill.

The upfront cost of an electric water heater can be far lower than that of a gas water heater, but in the long run, the running costs of the latter is lesser.

Heat pump systems

These systems use electricity to heat the water. Heat pump systems are more efficient than electric storage or gas storage systems because they use a heat pump to get the water hot instead of an element. A heat pump is like a refrigerator, but it is reversed so that it takes the heat out of the air and puts it into the water. Heat pump systems are becoming more popular because they save money on energy bills.

What temperature should a hot water system work at?

Most hot water systems work best at around 55 degrees Celsius. At this temperature, the water is still cool enough for basic tasks such as showering and hand washing but it is warm enough to provide comfort on really cold days. Most electric storage or gas storage systems can't be set above 60 degrees Celsius because they may not be able to heat the water any hotter. Most systems are designed to maintain a constant temperature of 60-65 degrees Celsius rather than maintaining an exact temperature that you set. This is known as "thermal runaway" and if your system does get into thermal runaway it will probably sustain some permanent damage. If your system uses natural gas, LP gas or LPG, you should be sure that its maximum operating temperature.

How many kWh does it take to heat hot water?

The amount of energy used to heat your hot water depends on the temperature that you want and the type of hot water system that you have: If you use an electric storage system, it will use about 4.3 kWh for every hour that it heats the water to 60 degrees Celsius. For example, if you take 5 showers a week and each shower uses about 8 minutes of hot water at 60C, then your system will use about 22 kWh every week (5 x 8 x 4.3). The size of your home and how often you do laundry or run other appliances such as dishwashers also affects electricity usage. If you use a gas storage system, it will use about 1.5 kWh for every hour that it heats the water to 60 degrees Celsius. For example, if you take 5 showers a week and each shower uses about 8 minutes of hot water at 60C, then your system will use about 7.5 kWh every week (5 x 8 x 1.5). If you have a heat pump system, it will use about 0.8 kWh for every hour that it heats the water to 55 degrees Celsius. For example, if you take 5 showers a week and each shower uses about 8 minutes of hot water at 55C, then your system will use about 4 kWh every week (5 x 8 x 0.8).