ᐅ Is the district heating consumption too high for a KW 55 house?

Created on: 21 Nov 2019 15:55
T
Tom1971
Hello,

We have just taken over our house from the developer. It is a detached KfW Efficiency House 55, the blower door test was passed with flying colors, so the house is airtight. We have underfloor heating, and the heating system is connected to a district heating network (heated area 230 square meters (2475 square feet)). But now we have the following problem:

1. Within the first three days after handover, the calibrated meter recorded 470 kilowatt-hours of district heating consumption. Keep in mind that at the moment only the underfloor heating is running at 21 degrees (70°F), bathrooms and showers are not in use yet (we are moving in next month). So this consumption is exclusively from the underfloor heating.

2. When I extrapolate this to 30 days in November, this results in about 4700 kilowatt-hours of heating energy. Historically, November accounts for about 11.4% of the annual heating energy (source: Munich utility company averaged over all their district heating customers). Based on this, the annual consumption would be nearly 43,000 kilowatt-hours, or 185 kilowatt-hours per heated square meter per year.

3. According to the 2018 heating cost index for district heating, the average value is 133 kilowatt-hours per heated square meter per year, and this includes tens of thousands of buildings from the 1970s, 80s, and 90s with poor insulation. We are therefore nearly 40% above the average, which probably means 70–80% above the value expected for KfW 55 houses if compared.

Does this sound strange to you as well?

A technician for the heating system will visit tomorrow, but if they don’t find anything to explain the discrepancy, I will have to file a complaint immediately.

What do you think?

Many thanks in advance for your replies!

Best regards,
Thomas
S
Scout
21 Nov 2019 17:02
No, a underfloor heating system doesn’t have an automatic refill inlet—so your neighbor won’t find a geyser on their lawn because of it.

I would wait for the technician tomorrow.
T
Tom1971
21 Nov 2019 17:40
Thank you, that is somewhat reassuring. I’ve created a table showing the daily consumption and total usage, including a projection for November and the entire year, and I will present this to the technician tomorrow. Something must be wrong. I’ll keep you updated here!
Dunkles Dokument: Tabelle zum Fernwärmeverbrauch im Haus 40 mit roter Warnzeile unten.
G
guckuck2
21 Nov 2019 17:43
So if you show the technician a PowerPoint presentation tomorrow, he will understand it even better.
Just wait and feel free to share your experience here.
tomtom7921 Nov 2019 17:45
Hard as a hammer.. are you for real or just fresh out of university?
T
Tom1971
21 Nov 2019 17:47
Seriously. Why isn’t an owner allowed to do the calculations? Maybe I’m overreacting, and if the values hadn’t been so extremely high, I would have waited first. But this just looks pretty severe.
D
DanielHamburg
21 Nov 2019 18:14
And are you sure the unit kWh was read and converted correctly?