Which heating system is suitable for an old building apartment?

Hello, I bought an old apartment (60m²) where a more than 25 years old Vaillant gas boiler (heating and instantaneous water heater for hot water) is installed, I would like to replace it with a new modern heating system. The chimney sweep told me on site that I cannot install a condensing boiler, as three apartments are connected to the chimney and all of them would have to get a condensing boiler because of the chimney. Now I am looking for a gas boiler that is as economical as possible (not condensing), compact, wall-mounted, and above all quiet, which also provides a decent amount of hot water (in my old apartment the water pressure while showering always seemed too low to me). Does anyone have a recommendation? Best regards Ingo

There is really a lot going on in the forum here, 3 questions asked and not even 1 answer after 3 days, respect!:rolleyes:

Hi Ingo, the problem is not the pressure but the physics. Even the smallest heating-value boiler has enough power for your apartment but only produces moderately warm water. With an 18kW boiler, you get about 5 liters of warm water per minute in the flow-through principle. So if you want very good hot water performance, you have to choose a combination boiler with a hot water storage tank. That is, a storage tank that stores warm water. If the space allows it. Regards Scarfy

.....Does anyone have a recommendation?...

Yes, first carry out (or have carried out) a basic assessment. => Actual demand (power, energy) for heating and hot water!

v.g.

Thank you for the answers, the current heating system has 19/23KW, a smaller one would definitely be sufficient for the heating, the chimney sweep mentioned 11KW (then a condensing boiler with a flue directly through the wall would also be possible), but my 19KW gas boiler (condensing) in the old apartment definitely produced too little water pressure, even with a special showerhead there was no question of a massage jet, it was more like a moderate summer rain :rolleyes:. The new heating system is to be installed in a niche above the washing machine, the maximum space is 70cm wide, 60cm deep (preferably less, so that I can still put something on the washing machine). The ceiling height is just under 2.5m. A second option is above the toilet directly on the chimney, but then the unit would have to be extremely shallow (max. 30cm deep). I will find out what is available with hot water storage. Actually, I am against hot water storage, to keep water at temperature all day for max. 2x a day :cool: (and an electric instantaneous water heater is out of the question), isn’t there some kind of combination unit that, for example, has 11KW heating power but 30KW hot water power? Regards Ingo