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:
Is that the electricity consumption I should expect, or am I misunderstanding something? That seems very high!
Thank you in advance.
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.
S
Sebastian7921 Jun 2016 13:23This clearly shows once again that the KFW rating doesn’t really mean much.
We have KFW70 and are calculated at 38 kWh/m² (3.5 kWh/ft²)...
We have KFW70 and are calculated at 38 kWh/m² (3.5 kWh/ft²)...
T
toxicmolotof21 Jun 2016 13:43Sebastian79 schrieb:
This clearly shows once again that the KFW rating really doesn't say much.
We have KFW70 and our calculated consumption is 38 kWh/m² (4 kWh/ft²)...Well, it’s not quite that simple.S
Sebastian7921 Jun 2016 13:47No, not that bad, but some people seem to think that by building a KFW55 house, they've achieved an exceptionally high standard 😀.
To put it better: it actually tells you very little about the energy consumption – even less today than it did in the past.
To put it better: it actually tells you very little about the energy consumption – even less today than it did in the past.
T
toxicmolotof21 Jun 2016 14:28The KfW standard is not meant to compare money saved down to the last euro.
The absolute value already reveals a lot (under laboratory conditions).
A typical house of this building type would require even more energy. That’s what it shows.
If you want a nice, custom house design (or are forced to due to building permit / planning permission requirements), you have to pay the price for it.
Considering that every room in our house has four exterior walls, I find the value very good.
The absolute value already reveals a lot (under laboratory conditions).
A typical house of this building type would require even more energy. That’s what it shows.
If you want a nice, custom house design (or are forced to due to building permit / planning permission requirements), you have to pay the price for it.
Considering that every room in our house has four exterior walls, I find the value very good.
S
Sebastian7921 Jun 2016 14:32How many rooms does your house have?
I know what the KfW value stands for, but apparently many others don’t, because they only look at the number and then say a house is good or bad... which is nonsense.
I know what the KfW value stands for, but apparently many others don’t, because they only look at the number and then say a house is good or bad... which is nonsense.