There are several technical systems that are used as water heaters. Hot water boilers or boiling water devices only heat the water shortly before use or, with a storage function, keep warm water ready at all times. Closed boilers are also known as hot water storage tanks . Open water heaters consist of a tank container in which the water is located without separate pressure. In most cases, the necessary water movement is made possible by gravity by placing it above the tapping point.
The most typical representative of closed water heaters is the instantaneous water heater. With him, the water is only heated at the moment of withdrawal by means of pressure being passed through a heated pipe system . Instantaneous water heaters quickly consume a lot of energy, which is supplied by electricity or gas.
Technical types and modes of operation
Apart from centralized hot water tanks, water heaters are locally used devices. They are usually placed in bathrooms or kitchens and have only a limited supply radius.
As with the central hot water supply, the heat loss on the transport routes must be minimized. The longer the distances, the more the efficiency and effectiveness drop.
The technology in the devices allows different types of hot water supply through hydraulic or electronic control. Some models require a certain lead time, which makes them unusable for removing small quantities.
The heating principle of the devices works as follows:
- Closed boiler / storage tank: The water is constantly left at the set heating temperature and can be tapped at any time without delay.
- Open boilers and boiling water devices are switched on before the need for hot water and heat the water they contain in a few minutes.
- Hydraulic instantaneous water heaters “start up” when the flow of water begins and heat the flowing water in a pipe circulation system. Usually 3 temperature levels are possible.
- Electronically controlled instantaneous water heaters generate a precisely adjusted energy supply in their pipe system in order to deliver and maintain a set temperature. They deliver without delay.
Cost of a water heater
Simple open boilers or boiling water devices are available for purchase prices of less than 100 euros. The power consumption depends heavily on how it is used. If only the amount of hot water that is used is produced in a very targeted manner, the electricity consumption can fall below that of instantaneous water heaters.
Cost of a water heater
Electric water heaters with more precise control technology can draw a high degree of efficiency from the electricity they consume. Instantaneous water heaters in the price range between 100 and 300 euros can be operated very efficiently.
In practice, however, electricity-operated boilers are economically no more than an emergency solution because of their “waste” of heat output, which is difficult to avoid.
Electricity or gas
If a gas water heater can be installed instead of electricity, the energy consumption for hot water is lowest. However, the higher efficiency and profitability are offset by higher acquisition costs. A gas instantaneous water heater is significantly more expensive than the electric version, both to purchase and to install.
In addition, there is a necessary and mandatory annual maintenance, which increases the cost of a gas-powered water heater.
The ratio of around 1 to 4 between gas and electricity can be used as a basis for pure energy costs . For gas operation, however, the following factors still have to be allocated:
- Service, maintenance and acceptance
- Gas meter rental and gas connection fees
- Operating electricity costs for the ignition technology
Soft factors of your needs profile
In order for you to achieve optimal efficiency and profitability with regard to your hot water consumption, the adjustment to your needs, your heating system and your consumption behavior is crucial. Apart from the energy source, you develop an individual consumption profile through bathing, showering and cooking habits.
When planning your hot water supply, you should put this profile at the center of your purchasing decision. The number of people, age and family situation also offer further starting points.