ᐅ Is the house well insulated?

Hello,

What do you think of the following house and which KFW energy efficiency rating could be achievable with it?

112 sqm (1,205 sq ft) according to living space calculation
411 m³ (14,502 cu ft) volume
340 m² (3,660 sq ft) building envelope area
0.24 H’T transmission heat loss
0.828 1/m A/Ve
170 sqm (1,829 sq ft) exterior wall area
10.9% window-to-wall ratio

Foundation slab U-value 0.239:
5 cm (2 inches) WLG035 perimeter insulation → 20 cm (8 inches) foundation slab → 8.5 cm (3.3 inches) WLG035 insulation → underfloor heating → screed

Walls U-value 0.211:
36.5 cm (14.4 inches) aerated concrete with a lambda value of 0.08

Intermediate ceiling ground floor ↔ upper floor U-value 0.57:
20 cm (8 inches) thick reinforced concrete with 5 cm (2 inches) external formwork insulation

Roof slopes and upper floor ceiling U-value 0.17:
with 24 cm (9.5 inches) mineral wool insulation between rafters

Windows U-value 0.98:
Triple-glazed with Ug-value 0.55

Decentralized ventilation system with 4 exterior wall units and heat recovery of 90,x%.
Decentralized ventilation system with 3 exhaust units in wet rooms without heat recovery.

No bay window, dormer, conservatory, basement, or windows in roof slopes
4 floor-to-ceiling windows facing southwest (60° deviation from south towards west)
5 sqm (54 sq ft) solar thermal for hot water (without heating support, 60° deviation from south towards west)

Gas condensing boiler heating and underfloor heating throughout the house

Thanks in advance for your responses!

[QUOTE="BauProjekt14, post: 62254, member: 21518"]...what do you think of the following house and which KFW rating can be targeted with it?...[ /quote] What is the deeper purpose of such quiz-like surveys, which realistically can only be answered reliably by the person preparing the certification, provided they do it correctly!

Best regards

I often read sentences here like "Never sufficient for KFW xyz."
If someone makes such statements, they should have expertise in the subject matter, right?
It should be easy for a professional to assess the data I provided, or is there something important missing?

I thought for this type of calculation you pay a fee to someone who is trained for it 🙂

BauProjekt14 schrieb:
I often read statements like "Never sufficient for KFW xyz." If people make such claims, they should actually have expertise on the subject, shouldn’t they?...

On the internet and in forums, many opinions are expressed, often by anonymous advisors without any professional training. The actual reliable value of these claims is easy to count on one hand.

Best regards.