ᐅ Extremely High Pellet Consumption (200 kg in 3 Days) in a KfW 70 Multi-Family House!

Created on: 9 Nov 2016 14:35
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rudiherbert
Hello,

I just noticed the following regarding our pellet heating system (6-family new build, KfW70 standard). This is a new build and the first winter...

The consumption in October (which was very mild here) was 1000 kg.
Currently, the consumption is 200 kg over 3 days!
Projected, that would be 2,000 kg per month!
Although temperatures have dropped somewhat, there is still no sign of a harsh winter.

Here is what I observed about the pellet heating system (Eta 20-30).
The underfloor heating temperature is 56°C (133°F) with an outside temperature of 1°C (34°F).
Supply temperature to the underfloor heating in the boiler room is only 30°C (86°F)? The return temperature is the same?
The supply temperature shown inside the apartment is 38°C (100°F) when the room thermostat is active, and 20°C (68°F) when inactive.

The buffer tank is supported by solar thermal collectors on the roof (for domestic hot water and heating).

I am certain that this consumption cannot be correct!
The new build is well insulated. The building is dry. Everyone heats reasonably and ventilates correctly.

2,000 kg of pellets per month in winter is extremely high!
In October, we used 1,000 kg.
In summer, about 500 kg per month.

Before contacting the heating technician or property management, I wanted to get some advice here.

Thank you.
R
rudiherbert
9 Nov 2016 15:12
BeHaElJa schrieb:
No, he writes 200 kg over 3 days... that would be more like 6 tons – right?

Exactly! I wrote 2 tons! 200 kg over 3 days means 2 tons over 30 days! And I consider that quite high for these temperatures and a KfW70 new build.
A
Abzahler
9 Nov 2016 16:09
Before you address the actual problem, please provide more proposed solutions including the calculations showing the likely monthly consumption! :p
AOLNCM9 Nov 2016 16:26
How many square meters (square feet) of living space does the heating system need to cover?
L
Legurit
9 Nov 2016 16:36
😀 Sorry. Brain freeze. Well, just because you think so doesn’t mean it is — you’re not the ultimate authority 😉
R
rudiherbert
9 Nov 2016 16:45
AOLNCM schrieb:
How many square meters of living space does the heating system need to cover?

Hello.
New build summer 2016
Living area approx. 550 m² (5920 sq ft)
6 units
KfW 70 standard
Solar collectors on the roof for washing machine and heating
Underfloor heating with individual room thermostats
ETA pellet system 20-32 with buffer tank

Regards and thanks
Musketier9 Nov 2016 17:30
I have to admit, I’m not very familiar with all the KfW calculations. Still, I have the impression that a pellet heating system disproportionately improves the key values used for the KfW calculations. Most people here are probably aware that these values don’t reflect the actual energy consumption.

In the case of this multi-family house with a pellet heating system, this means, conversely, that the house doesn’t actually have to consume very little energy, but rather that the house has achieved the KfW 70 standard because of the pellet heating system.

Please correct me if I’m mistaken.