ᐅ House electricity consumption – what is your usage?

Bookstar schrieb:

I think the household certainly has 5,000 kWh. That leaves 5,000 kWh for the heat pump. Fits.

Assuming the numbers are correct, I would say something doesn’t add up.
If the heat pump draws 5,000 kWh of electricity, the house would have used around 20,000 kWh of heat energy, or the heat pump’s annual performance factor (COP) is between 2 and 3.

If, as previously assumed, the delivered heat output is around 10,000 kWh, there would likely be no problem.

Reliable figures are needed to properly evaluate this.

Joedreck schrieb:

Assuming the numbers are correct, I would say something doesn’t add up.
If the heat pump’s electricity consumption is 5000 kWh, then either the house required about 20,000 kWh of heat output, or the heat pump operates with a seasonal performance factor between 2 and 3.

If, as previously assumed, the delivered heat output is around 10,000 kWh, then there’s likely no issue.

We need accurate figures to properly assess this.

For a heated area of 240 m² (2,583 ft²), 5 kWh per day could be realistic. That would translate to only about $90 heating costs per month. It might indicate a seasonal performance factor between 3.5 and 4, which is quite average!

Depending on the indoor temperature and location, it could even be pretty good! We simply don’t have enough information.
It’s unlikely to be heat output though, such an efficient pump doesn’t really exist 😀

teh_M schrieb:

Interesting thread, I felt a bit bad about our 200W base load :p

Since the beginning of October, we have used about 780 kWh. It has been exactly 78 days since we installed the SMA Home Manager, so roughly 10 kWh per day (2 adults and 2 small children).
Of that, 213 kWh was self-consumption + 207 kWh from the battery storage, and the rest was purchased from the grid.

The photovoltaic system generated a total of 9,837 kWh over the entire year (10 kWp, southwest orientation with a flat roof at 8°).

I have no idea how such a low consumption is possible! There’s no heat pump installed, right? Do you heat with gas?

I’m just asking because until December 12, we didn’t turn on the heating and still had a monthly consumption of 450–500 kWh, and we already paid close attention to only drawing power when the sun was shining. See screenshots.

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We use about 150 kWh per month 😀 but we heat with gas.

We don’t have a heat pump, I forgot to mention that. We heat our 150 sqm (1,615 sq ft) house with district heating (KfW40+ standard). Since moving in at the beginning of August, we have used 2000 kWh of heat for both hot water and heating. With an annual performance factor of around 3 to 4, that would mean about 500–600 kWh of electricity consumption.

The hot water might partly explain the difference, since you also use a heat pump for that, right?

My plan is to cover the ongoing heating and electricity costs with photovoltaics, and that might actually work out: It looks like we will need about 6,000 kWh of heat annually. The goal for electricity is to only have to buy about one third from the grid. The cost per kWh of heat is 5.1 cents, with no base fee, so that’s roughly 300 € heating costs per year. Electricity costs about 30 cents per kWh (excluding the base fee), so around 360 €, or a bit more. This matches quite well with the income from the photovoltaic system, which consistently produces between 9 and 10 MWh per year.

We could save more by optimizing the base load. At a constant 200 W, that adds up to 1,700 kWh per year, nearly 50% of the total consumption. That includes some luxury items like a Synology NAS, some smart home devices, ventilation, network equipment, and cameras...

Maybe your base load is also quite high?

Bookstar schrieb:

For 240 m² (2,583 sq ft) of heated area, 5,000 kWh could be reasonable. That would mean heating costs of only 90 Euros per month. It could correspond to an annual performance factor between 3.5 and 4, which is quite average!

For a KFW 55 building of this size with a heat pump, I would expect that a 5,000 kWh electricity consumption does not necessarily indicate an optimal heat pump setting. But of course, you can just let it run.