Old building requires new heating system

Hello everyone,

we are in the process of buying an old building that has only been heated with electric radiators until now. Since this is absolutely uneconomical, something new needs to be installed.

The house was built in 1890. It has a living area of 170m². This should be divided into two units (50+120m²). These will be occupied by us and my sister, so the consumption should be measurable separately. The house has no basement, so the boiler should be installed on the upper floor due to space reasons. The attic is not insulated yet, but this will be done first because it is going to be inhabited. Therefore, the ground floor, the upper floor, and the attic should be heated. Bathrooms will be installed on every floor.

We have thought about a gas combi boiler without a water storage tank, as well as aluminum composite pipes. So everything must be newly installed, built, and fitted. The gas connection still has to be provided by the city (approx. €2000), and we will of course leave the connection to the boiler to a professional company.

I am not worried about the craftsmanship since we are quite skilled in that area. However, I wanted to hear your opinion, as I have not installed a new heating system before. It would be great if you could recommend a few things.

Best regards

Masabidi

Gas combi boiler means with instantaneous water heater? I wouldn’t do that, because the instantaneous water heater is better installed directly at the point of use so that there are no long distances for the hot water. I would accordingly take a normal condensing boiler and then install the instantaneous water heater directly next to the shower(s). Then the boiler does not have to run in summer either. The instantaneous water heaters must be applied for at the municipal utility company. We have 2 with 22kW, that was only possible under the condition of a load shedding relay (if one is running, the other cannot run). For more distant outlets like possibly the kitchen, you can also use an under-sink instantaneous water heater with 3.5 kW or something like that, which is sufficient. An alternative to the instantaneous water heater would also be a domestic hot water heat pump, e.g. the very affordable Ariston Nuos as a wall unit with 80 or 100L (we also considered that back then, but ended up sticking with the instantaneous water heater due to the low consumption costs).

When the bathrooms are renewed and the gas heating as well, then get a boiler with a proper hot water storage (120-180l) and nothing dlh or similar. With three bathrooms and two kitchens, the combination boilers with small or no storage are no longer sufficient. Better a heating system with some storage and low output. If possible, put the heating system in the attic and the three bathrooms one above the other.

Are you planning to rent to your sister forever?
If not, I would consider two separate heat generators.
That makes many things easier.

Thanks first of all for the numerous responses. I actually didn’t want to install a tankless water heater. I was told that modern combi boilers manage it without any problems, but it’s good that I’m asking here. That shows you shouldn’t always rely on the statements of individuals.

Unfortunately, the boiler can’t be placed in the attic for space reasons. For the kitchens, I could imagine using a tankless water heater there. If it is really better or more efficient, a hot water storage tank could be installed.

The apartment will be rented to my sister, so she needs separate meters.

I quickly made a sketch of how I actually intend to do it.

It would be nice if you could maybe even recommend suitable boilers or say which manufacturer is advisable and which is rather not.

Have a nice Sunday

All right, thanks for the info.