The dishwasher at the hot water connection


In addition to the question of whether a dishwasher or manual rinsing is better, there is another question that concerns many consumers: what about the dishwasher and a hot water connection? Is a connection possible and why is it not always advised against it? Below we give answers.

Not easy to answer, whether a hot water connection makes sense

Even with washing machines, the question often arises: does it make sense to connect this with the hot water connection when connecting a washing machine? Also in relation to dishwashers, this question arises again and again. In addition to the question of whether flushing by hand or on the dishwasher is better, this is the next frequently asked question of many consumers.

It depends on many factors

Incidentally, whether it is better to clean by hand or by machine, we also give an answer in the following article: Water consumption of a dishwasher. Regarding the hot water connection it gets a bit more complicated. It depends very much on a variety of individual factors on site.

  • Type of hot water supply
  • Type of water heating
  • whether additional technology (ballast for mixing) should be installed
  • technical details and thus also the age of the dishwasher

Connection to the hot water to save electricity

The connection of the dishwasher to the hot water connection is usually based on the idea of ​​saving energy costs. Finally, the already heated water is yes in the water tank of the house or is heated before consumption. Whether the connection is worthwhile or not is, in principle, a math problem, in which the above-mentioned factors must be taken into account.

Modern dishwashers need under 1 kWh

Up to a few years ago, modern dishwashers were regarded as energy-saving if they required a maximum of 1.5 kWh of energy. However, latest-generation dishwashers generally require less than 1 kWh per cleaning cycle. This includes the cost of heating the water.

The more modern the dishwasher, the lower the savings

The more modern the dishwasher, the lower the possible energy savings. Now it is just as important how the water is heated, stored and passed through the house. There are hot water circuits in which the hot water circulates. In other systems, it is stored in a heat storage or heated immediately prior to use.

Every heat loss in the house system counts

This is accompanied by the length of the water pipes, through which the hot water must be transported to the dishwasher. The longer the way and additionally dependent on the line insulation, a lot of energy is lost here as well. There are hardly any savings left on dishwashers of the latest generation. In older dishwashers, however, it could be quite rewarding.

Is the domestic water heated sparingly?

But there is another aspect: how is the water heated at all? Again, there are a variety of systems:

  • Gas (boiler and water heater, for example)
  • Electricity (boiler and water heater)
  • Photovoltaic with hot water tank or water circulation
  • combined with heating (other regenerative energy such as wood or pellets)
  • combined with heating (fossil fuels such as gas, fuel oil, etc.)

Calculate the detailed costs for your hot water

So you first have to calculate how expensive it is to generate your domestic hot water and how much energy you lose during transportation through the piping system. These costs are then compared to the energy consumption of your dishwasher. But even with efficient methods such as solar technology, the effort is too high, at least for modern dishwashers.

Do not neglect the heat loss in the pipe system

If necessary, there is another point. In some houses immediately hot water comes from the hot water pipe. In other houses, there is again a certain lead time of cold water, but this can vary if, for example, the mixer tap on the same connection as the dishwasher previously turned on. So it can not really be controlled.

Never use only very hot water

This is an important aspect, because the washing power is reduced when rinsing immediately with hot water. Many dishwasher manufacturers also provide specific information. The background is that protein (amino acids) and starch are not as readily soluble at high temperatures as they are at colder water temperatures.

Chiller water is important in the cleaning process

However, dishwashers do not generally heat the water from the first second, but after a certain time or increasing. The cleaning agents and rinse aid may also be adjusted so that initially cold water runs into the machine. For Kombitabs this can mean that they do not dissolve correctly.

Solution: a ballast mixer

But of course there is a possibility for that. You can connect a pre-mix mixer or a ballast to mix hot and cold water and then set a specific temperature (usually between 40 and 50 degrees Celsius). But this brings back several hooks: with washing programs up to 95 degrees, the dishwasher still has to heat the water independently.

This structure can quickly destroy the cost savings

In addition, the cost of such a ballast is not insignificant. This can quickly exceed the costs that are saved. Simply because the saving effect of modern dishwashers is not so significant anymore. However, if you want to run a power-intensive, older dishwasher longer and save energy, the described options would be quite interesting.

Tips & Tricks

If you have decided to connect your dishwasher to the hot water supply, this is not a big hassle. Turn off the shut-off valves, turn off the dishwasher and unplug the power cord. Now the inlet hose is disconnected from the cold water hose and connected to the hot water hose. For more information about the necessary mounting material and tools, see "Connecting a dishwasher".


Video Board: How To Connect Water Supply To A New Dishwasher - Step by Step