dirstir wrote: All sellers count for every 100 m2 of 10 kW plus 5 kW of stock, but this is unnecessary in new buildings due to thermal insulation, so in your case a 25 kW stove will be the best solution.
Because it is in their interest to sell a larger-more expensive boiler. 100W / m2 were the norms from 30 years ago. People don't take into account building insulation? Does giving the demand to the average daily temperature (!!) -20 degrees C make any sense? When were these tempreatures? 10 years ago for a few days?
The average temperature of the heating season is + 3-4 degrees C, not -20! And here, 30-45 W / m2 will actually come out, which gives a real 8-max12kW + a small reserve for DHW, thermophilic, weaker fuel, poorly cleaned boiler, etc. So, as a colleague wrote
@ irus.m 15kW and can't do any more. The boiler is supposed to burn, not smolder at 45 degrees, and then overheat at a standstill, because there is no heat reception from the blow-bys. Efficiency is going bad.
Zbigniew Rusek wrote: But 3kW for hot water is far too little. After all, obtaining a normal stream of hot water by the flow-through method requires (if the water is very cold, e.g. in the middle of winter) at least 18kW of power. After all, a bathroom stove is either 19.2 kW or 23.6 kW. Of course, only a combi boiler will heat the water in flow.
And what is the point of comparing to flowing DHW? 2kW is enough for the thermal bath and what?
When the boiler has 15kW, all power goes to DHW, - for example, work with DHW priority works like this. It will heat up in several minutes and return to heating CO. I can assure you that no one will get cold in a well-insulated house if the radiators do not heat up during this time, no one will even notice it.
