ᐅ Reliability of an energy calculation for KfW 55 – is it too high?

Created on: 20 Jun 2016 18:01
W
WT1987
Hello everyone,

For our new build with 2 full floors and a basement, we have now received a calculation for the entire KfW application. However, it seems to me that the numbers are being calculated quite high or may even be incorrect.

Some data about the house:
  • Architect’s plan shows living area: ground floor 75m² (807 ft²) & upper floor 70m² (753 ft²) (difference due to open space)
  • Clear ceiling height: ground floor 2.7m (8 ft 10 in) & upper floor 2.5m (8 ft 2 in)
  • Basement is unheated, air-water heat pump located in the basement
  • Attic is not developed
  • Air-water heat pump with ventilation system including heat recovery
  • The expert assessor calculates a usable floor area of 277m² (2,982 ft²), which seems very high to me! He then uses this to estimate electricity consumption and arrives at a final energy demand of 4,860 kWh/year

Is that the electricity consumption I should expect, or am I misunderstanding something? That seems very high!

Thank you in advance.
MarcWen20 Jun 2016 21:25
That can’t be correct, we are building a corner larger and have a primary energy demand QP of 23.4 kWh.
S
Saruss
20 Jun 2016 21:42
MarcWen schrieb:
That can’t be right, we are building a corner bigger and have a primary energy demand QP of 23.4 kWh.

But per square meter, so the size is already factored out?
MarcWen20 Jun 2016 21:54
Our first version also contained errors; I inquired again and it was then corrected.
  • Heated building volume 1386.8 m² (14,926 ft²)
  • Heat-transmitting envelope surface 745 m² (8,016 ft²)
  • Usable floor area 443.8 m² (4,776 ft²)
L
Legurit
20 Jun 2016 22:02
23.4 kWh/m²a (?) - his is 31.6 kWh/m²a, which is not that far off.
MarcWen20 Jun 2016 22:19
BeHaElJa schrieb:
23.4 kWh/m²a (?) - his is 31.6 kWh/m²a, which isn’t that far off..

Well, we are building about 50% larger and have about 25% less primary energy demand QP.
So I would at least want to follow up on that.
L
Legurit
20 Jun 2016 22:28
per sqm (per square meter)!!!