Company Lüumel, trench collector

Phew. That's a lot if you don't have well over 200m². We managed about 2700KWh last year with 125m² of living space. In the first years, an estimated 3500-4300kWh.

1. Our heat pump (brine/drilling) is relatively quiet. It is located in the basement with the door open and the stairwell open, and can only be heard in operation in the evening when it is really quiet (children in bed, TV off, etc.). When you close the door of the room, you can no longer hear it. 2. For about 240m^2 of space (of which 80 in the basement, included in the insulated building envelope, not all rooms actively heated there, but always > 16°C warm), I have used a total of slightly less than 10,000kWh of electricity for heating and hot water over the last 4.5 years. About 2000 kWh of that was for the screed heating program. Additionally, there was a heating system maintenance a week ago - the first one - everything is fine (thus no special maintenance costs, such as replacement parts or similar).

Do you have a heat meter? What kind of KfW does your house have?

KfW70 Energy Saving Ordinance 2009 according to the calculation before construction. Somewhere in the forum there are details, the house was subsequently built with somewhat higher-quality materials (e.g. significantly better insulating window frames, slightly thicker basement insulation, roof AND attic insulated...), so that it (technically "anyway") might also correspond to a KFW55+. The amount of electricity was determined with a calibrated electricity meter. As a heat meter I use the internal one of the system, the values during heating correspond with those I calculated (with the real components!) as heat losses of the building, so it should be reasonably accurate. However, I have deliberately not specified a heat quantity. Incidentally, I have very meticulously adjusted the heating curve and other parameters of the heating system to the house (for example, although I installed individual room controllers, all of these are deactivated without loss of comfort, i.e. the room temperature fluctuates less than 0.5 degrees C during the heating months).

We have 140 sqm, half of the rooms are at around 22-23 degrees room temperature and the rest at 20 degrees room temperature. Since we keep having malfunctions, we should always switch on the heating cartridge. Not for a long period, maybe one week with the heating cartridge. Every technician sets the heating differently. Who could I contact to get good advice and reduce electricity consumption? 8000 kWh per year is clearly too much for us.

I have adjusted the heating curve similarly to Saruss and deactivated most of the individual room controllers (ERR). By default, Lüumel probably specifies a slope of 0.3 and a shift of the heating curve of +2° during the day and 0° at night. Possibly also a comfort increase of 1-2° at selected times.

We had the ERR everywhere as a limiting element. My idea was whether we could lower the heating curve a bit to save energy. I started with the rooms with the highest temperature demand (living room and bathroom). With the ERR fully turned up and the valves in the heating circuit distributor fully open, it was too warm for me in winter. So I lowered the slope to 0.2° and shifted the heating curve slightly upwards. Then it was a bit too cool, especially in the transition period, so I shifted the heating curve further up during the day and at night until the two warmest rooms matched. The desired temperature was then reached by us at +5°. Then I went ahead and fully opened the ERR in the other rooms. In most rooms, of course, it was too warm. So I adjusted the flow in the valves in the heating circuit distributor so that the temperature in these rooms was correct with fully opened ERR. Since the valves are now always open and thus constantly powered, I removed the automatic controllers in the heating circuit distributor and set the ERR in the rooms to zero. This way, no power flows. The ERR in the guest room is still in operation, as adjustments should be made there depending on usage.

A small tip: write down what you do and how it affects things, and don’t change too much at once. The whole thing is not done within 14 days but took us well over 2 years.