The mistake in brief
The most common mistake when charging a fixed electricity rate is trying to fit one price to very different usage patterns. The family that comes for three days to sleep and shower pays the same as the group that runs the air conditioning day and night and uses the sauna. In practice, this means: the economical guest pays too much, and the host covers the bill for the guest who uses a lot.
This almost always happens because the fixed amount is based on an average week, while consumption per booking sometimes varies three to five times over. A week in summer with air conditioning and pool pump uses considerably more than a quiet autumn week without heating. If you apply one amount to that, you're essentially choosing either to charge too much or to cover the difference yourself.
Why a fixed amount seems so attractive
A fixed amount looks fair and straightforward: the guest knows in advance what he pays, and you don't have to measure or read meters. For a short stay in a small apartment without air conditioning or sauna, this often works fine, because consumption there hardly varies. It only becomes difficult once there are appliances in the home that can significantly increase consumption, such as air conditioning, a sauna, a hot tub, or a charging point.
What goes wrong in practice
Suppose you charge a standard 15 euros for electricity per booking, based on average consumption of around 30 kWh per week. A modest guest in spring might use only 15 kWh and thus pays double what he actually uses. A guest who runs the air conditioning continuously during a heat wave and heats the hot tub in the evening quickly reaches 80 to 100 kWh — and pays exactly the same fixed amount. The difference, often tens of euros per booking, simply comes out of your own margin.
The second problem is less visible but equally annoying: guests who feel disadvantaged sometimes let that show in their review. A fixed amount that is too high for one guest and too low for another creates exactly the kind of confusion that ends up in reviews, while nobody — neither you nor the guest — can say exactly how much was actually consumed. If you want to know how much an average home actually uses per week, you'll find that worked out in the knowledge base with consumption by dwelling type.
How you recognize the mistake before it costs you money
A good rule of thumb: if your home has equipment that can increase consumption by more than a quarter — air conditioning, sauna, hot tub, electric heating, a charging point — then a fixed amount is almost always too rough. For a simple apartment without that kind of equipment, the variation is small enough that a fixed amount does little harm. If you're unsure whether your situation falls into the first or second category, the selection tool with a few short questions gives you an immediate indication.
What does work: billing for what is actually used
The way to structurally prevent this mistake is to bill electricity based on actual consumption instead of a fixed amount per booking. This does require a way to make that consumption visible without you having to note down meter readings yourself or make corrections afterwards. With a system where the guest buys kWh himself via a QR code in the home and sees his consumption live, every guest automatically pays for what he himself uses — the economical guest just as much as the guest who uses the sauna. How such a measurement and billing system works exactly is explained on the page that shows where the information comes from.
The switch from a fixed amount to billing based on consumption doesn't have to be a major operation; it's mainly about choosing a system that fits the number of properties you rent out. An overview of what this costs per property or charging station can be found on the pricing page with rates per object.
Finally
A fixed electricity amount is not a bad choice in itself, but only becomes a problem once consumption in your property can vary considerably. If you want to know in a few minutes whether your situation is susceptible to this, the free quick-scan will get you started, and you'll find all the background information neatly organized in the knowledge base.