Heating load calculation & layout plan DIN: Is a new calculation necessary?

So, the calculation was made before I decided on the ventilation system, according to the heating engineers' statement, but it is not so important even for the individual room consideration. Rather, about 80% of the additional demand due to ventilation can be taken into account again in the total heating demand because of the heat recovery.

: You mean it does not bring much for the overall room temperature?

I do not understand the statement. If the room is ventilated with windows, you ventilate with outside temperature, which is included in the calculation with the NAT. A minimum air exchange of 0.5 x room volume /h is assumed. With a controlled residential ventilation system with heat recovery (WRG), however, you do not ventilate with NAT but with a significantly higher air temperature (depending on the degree of heat recovery). Then, with the same ventilation volume per day, you also have a significantly lower ventilation heat loss. And yes, this is calculated for each room individually, depending on the ventilation concept. Usually, in a single-family home's bathroom, there is only exhaust air, meaning the incoming air volume then has the air temperature of the air-supplying room. The controlled residential ventilation with heat recovery changes not only the total heating load but also the room-specific heating load individually, depending on the function of the room (supply air - exhaust air). And you do not have an increased demand but less heating demand. Unless the windows during window ventilation always remain closed...

Yes, of course. I basically meant less additional heating demand due to ventilation with controlled residential ventilation vs. manual ventilation... Thanks for explaining the relevance also for single-room ventilation! I think he just wants to proceed according to scheme F or not be contradicted. That's why I want to prepare here. So I'll note for myself: Ventilation concept must be finalized (demanded, he must have also created or commissioned it) then based on that, a new room-specific heating load calculation with specified room temperatures. I will try to have him or the general contractor do that, because there is clearly a difference in the heating system design if you have central controlled residential ventilation with heat recovery or not. He knew that I was interested in a ventilation system; he just shouldn’t have commissioned the calculation before I had definitely decided on controlled residential ventilation yes or no. Or he must, if necessary, accept that I commission another firm and he takes over the planning from them...

What does 6100 KW heating load actually mean? That’s not KW/h, so how do I now calculate it into an annual demand? Can I even calculate a rough annual heat energy demand with it?

Thanks and regards

Tolentino

Simply calculate the baths with 20°C instead of 24°C. Then it should also work with 30°C flow temperature. If the heating engineer complains, simply argue that the missing 4°C are covered by a building-side purely electric towel heater. This and the unconsidered internal or solar gains and the oversizing due to the unconsidered controlled residential ventilation ensure that the place still gets warm.

So you mean I can skip a new calculation? I actually want more than 20°C in most living rooms...

I am repeating myself, but still.

Do it like OWL commissioned, preferably the same office that OWL used for the calculation, with your desired temperatures.

You have a construction project here that costs you hundreds of thousands, so if I were unsure about the quality of the calculation by the HB, I would not hesitate to spend a few hundred euros to get an independent second opinion.

yes, I agree. Just need to get the statement from Heizi that he will then also build according to the interpretation / calculation.