Solar yield is not readable

Washing machines and dishwashers connected to hot water are not worth it anyway. Your heating engineer has already told you the truth, even if it's the first time now. These things are important for approval purposes. Nevertheless, they obviously have to work ;-)

Whether the ST works can be seen on the thermometers at the solar station.

The rest, as said, is subject to an additional charge. Turning off the heating system is not always possible, as the controllers often want to work together with the systems.

Even if you could read it off, the values are worthless (at least for our Vaillant). Only one thing is important to me: We have had the gas boiler completely off for more than 4 weeks now, meaning gas consumption is 0.0. When our buffer is full (95 degrees), that is enough for about 5 days of hot water without sun. So we are definitely saving :)

Moin Moin

Suppressing the reheating should actually always be possible.
If necessary, lower the storage temperature significantly.

Alex, how do you come to the conclusion that supplying the washing machine and dishwasher with solar thermal is not worthwhile?
The figures are certainly not precise, but:
Electricity €0.30 per hWh
Gas €0.08 per kWh
Solar €0.00 per kWh

Olli

Alex, how do you come to the conclusion that supplying the washing machine and the property with solar thermal is not worthwhile? The figures are certainly not precise, but: Electricity €0.30 per hWh Gas €0.08 per kWh Solar €0.00 per kWh

Because dishwashers need cold water! Especially fats should be treated cold first before warm water is used. The machines use cold/warm water alternately depending on the program to achieve their cleaning results, e.g. pre-washes and intermediate rinses do not require warm water at all. Well, if you already have solar thermal in abundance, it doesn't matter, but if your hot water costs something, especially in winter, you actually lose money. In addition, dishwashers use very little water anyway, meaning the hot water line should be connected to the circulation so that cost advantages can really be realized; otherwise, the machine will heat electrically again after 2-3 liters of cold water flow in, even though hot water is needed. By the way, about half of the heat energy in a dishwasher is absorbed by the dishes when washing machine water flows in, meaning the dishwasher will always heat electrically afterwards. So you must not believe that the energy demand of the dishwasher can be massively reduced if it is connected to the washing machine.

The washing machine must have a separate connection, among other reasons because washing programs below the inlet water temperature otherwise don’t work. It's just stupid to start a 30°C gentle cycle and have 50-degree hot water flow in. There are only a few models that have a separate hot water connection, and they cost, with otherwise identical features, about €200-300 more.

Then there is the investment for piping, ideally circulation (if not "already there").

You also have to consider that dishwashers and washing machines are rarely on more than once a day each, meaning the hot water in the supply lines regularly cools off, which is not conducive to the idea of energy savings (yes, the heat is still in the heated casing but simply doesn’t end up in the dishwasher or washing machine). Circulation helps there too, but it causes both investment and ongoing costs.

We decided against it. I don’t need a new washing machine; circulation is a big hassle and the savings for the dishwasher with 10-12 liters of water usage are effectively zero anyway, no matter how you calculate it, simply because the amount of hot water there is lacking.

The numbers are certainly not precise, but: Electricity 0.30 € per hWh Gas 0.08 € per kWh Solar 0.00 € per kWh

I am not against solar systems, but the above prices, as you mentioned, apply if you rent (but are usually included in the rent). Otherwise, investment and maintenance costs come in, which are not negligible from a price perspective.