Connect WW treatment to existing heating

The renovation of our two-family old building is imminent, and among other things, we will also renew the old drain pipes and zinc pipes of the water lines. Currently, a total of 3 instantaneous water heaters are installed, so the hot water preparation is electric. However, I am now considering connecting the hot water preparation in the basement to the existing oil central heating (built in 2000), including corresponding new piping and a large water storage tank/boiler next to the heating boiler.

The question is: is the Viessmann heating system "strong" enough to handle the hot water preparation in addition to the heating circuit? Will significantly more kW be required for this? Has anyone here done this before?

If the conversion remains reasonable, I would prefer this hot water preparation over the instantaneous water heaters, especially because the 3 instantaneous water heaters would also need to be replaced (to the current standard) and would not be cheap.

What do you think? The boiler is a Viessmann Vitola 100; the kW value is currently unknown.

Thanks for tips!

If anyone should make a statement here at all, then you should make an effort to determine the KW value of the heating system and maybe also provide the heated area and how many people regularly need hot water ;) ... otherwise, we can only all look for crystal balls and make dull assumptions.

Ok, sure, I'm looking for the data! ;-)

Four people are to be supplied with hot water. The total living area is around 250 sqm, a two-family house. 1x 180 sqm for us (2 people) and a 2-room apartment for rent for 1 or 2 people.

I still need to find the kW output of the burner. The entire central heating system was installed in the year 2000.

Is relatively uninteresting, as problems with the temperature in the house can only occur with a very tight design of the heating. I clearly do not suspect that here.

But: if the small apartment is rented out permanently, I would possibly prepare the piping there, but leave the [Durchlauferhitzer] due to better separation of energy costs. Overall, this is also more hygienic.

Furthermore, provide heat meters at the heating for billing. There is nothing more annoying than having to argue with tenants. This way it is easy to prove what they consume.

Thank you Joedreck, an interesting thought!

It would be easier to equip the rental apartment with a good modern tankless water heater, but our living area (main house) with a hot water storage tank via the heating system.

I'll keep that in mind for the conversation with the installer!

In my previous rental apartment, I had both at the sink: hot water from the pipe and a small boiler. The sink was on the same wall where the boiler was on the other side, so the path couldn't be shorter. Nevertheless, I appreciated having this alternative hot water supply outside the heating season. It was ultimately more efficient than turning on the big boiler. And you could draw hot water without causing temperature fluctuations for someone showering at the same time. So as a turbo, the boiler can be a blessing, even if at first glance you might associate it with outdated technology.