ᐅ Single-family house, 140 m², KfW Efficiency House 55 achievable through insulation and air-to-water heat pump?

SamSamSam schrieb:

Is 28°C (82°F) a typical target value or just an example?
I understand from this that the spacing should not simply be the same everywhere by default, but rather calculated for each room. However, it should be kept as small as possible to save heating costs (lower supply temperature), right?!

It was an example. Currently, the trend is toward 30°C (86°F) supply temperature and 26°C (79°F) return temperature.
Proper underfloor heating planning must take the following into account:

• desired room temperatures (typical default is 20°C (68°F) everywhere)
• room-by-room heat load calculation
• number of heating circuits
• length of heating circuits (e.g., one at 160m (525 feet) or two at 80m (262 feet) each – the latter is clearly better)
• flow rates
• pipe spacing (in my case, I ended up with a variety of 5/7.5/10cm (2/3/4 inches))

Each of these factors depends on the others.

SamSamSam schrieb:

Isn’t this only relevant when the heating system is put into operation? What influence does this have during construction?

Hydraulic balancing must be considered directly during planning (heating circuit lengths, flow rates...) and after installation, the heating system must be commissioned exactly as planned.

SamSamSam schrieb:

Who should I hire to have the heating system optimally adjusted if not the heating engineer?

Planned or adjusted? The optimal settings can only be determined during actual operation in winter (you’ll probably find the settings that suit you best only by the second heating season). Settings are personalized; the heating engineer provides the framework. Whether the heating curve needs to be adjusted becomes clear only once you live in the house and can easily fine-tune the heating yourself. For example, in the transition season, the heating might turn off too early because it’s already warm during the day but still cold at night. You need to figure that out for yourself. It’s similar to adjusting colors, contrast, etc., on a TV—fine tuning.

Thanks in advance for the detailed contributions here 🙂 They really help to get familiar with the topic.

nordanney schrieb:

Correct underfloor heating planning must take the following aspects into account:

Shouldn't the energy consultant also consider things like this? So that, as you also mentioned, the heating system can operate efficiently?
Otherwise, why would you pay so much money 😀 even if you get half of it reimbursed.

SamSamSam schrieb:

Thanks in advance for the detailed posts here 🙂 They really help to get into the topic.

Doesn't the energy consultant also have to consider things like this? So that, as you mentioned, the heating system can be operated efficiently?
What else do you pay so much money for 😀 even if you get half of it reimbursed.

They only have to ensure compliance with KfW55 standards. If that results in €500 (approximately $540) higher electricity costs per year, then so be it 🙂

SamSamSam schrieb:

Shouldn't the energy consultant also pay attention to things like this? So that, as you mentioned, the heating system can be operated efficiently?

See @Acof1978

KfW 55 is KfW 55... If the consultant does a proper job, of course they also look at topics like these or give tips. But that’s not the primary reason they are hired.

Acof1978 schrieb:

It only has to meet KfW55 standard. If that means €500 (about $545) higher electricity costs per year, then so be it 🙂

Crazy! 🤨
In my ideal world, I would expect this to be checked everywhere energy savings can be made! And that such savings through execution would automatically be taken into account.

SamSamSam schrieb:

In my ideal world, I would look everywhere energy can be saved and automatically consider those savings through proper implementation of measures.

The Emily strawberry world exists only on TV 😉. Apart from that, the biggest factor is the occupants. Anyone who wants 24 degrees Celsius (75°F) and always fresh air through tilted windows will have huge heating costs even in a KfW40 house. Those who are content with 20 degrees Celsius (68°F) and controlled mechanical ventilation will have low heating costs in an efficient house.
But yes, it would be great if all energy consultants looked not only at the raw numbers but also at the practical implementation.