... By utilizing the exhaust heat, condensing boilers achieve a 10% higher heating output from the same amount of fuel compared to conventional boilers.
But only if the design of the heating surfaces allows for appropriate temperatures for supply and return flow. In domestic hot water preparation, condensing heat utilization is usually not possible at all.
... Modulation means that modern condensing units are capable of operating over a range of heating outputs, e.g., from 3 to 17 kW.
There are already devices that achieve a modulation ratio of 1:10.
... Studies have shown that simply by replacing old devices with modern gas condensing boilers, heating costs of around 30% can be saved, ..
A bit bold. ;) The theoretically maximum achievable condensing heat utilization is about 11%. Considering domestic hot water preparation, perhaps 7..8% can actually be realized. Where do the remaining 22..23% come from? ;)
Moreover, general savings effects are very questionable since the starting point is always the existing condition of the system considered.
If this is already relatively good, only little additional savings can be achieved.
best regards