Electric heating instead of a furnace — what the installation must withstand

The scale of changes around us

The transformation of heating in our cities is truly happening: in Dzierżoniów, as part of the Warm Apartment programme, over a hundred heat source replacement projects were completed by autumn 2025 (according to city data on programme implementation), and in premises administered by Świebodzice MZN, solid fuel still heated about 60% of the stock (data concerns stock administered by MZN, not the entire city — according to the commune's status report for 2025). Thousands more such changes lie ahead — and each of them will burden the electrical installation more than anything before.

Power arithmetic — coolly

Roughly, an apartment needs several kilowatts of peak heating power in winter — proportionally more in a poorly insulated building. Meanwhile, the typical contracted power for an apartment is 4–6 kW for everything: heating, kitchen, washing machine, lights. The conclusion is simple: electric heating almost always means a discussion about power — sometimes increasing the contracted power is enough, sometimes increasing the connection power is needed, and in a multi-family building, the question about the condition of the main power supply lines (WLZ) is asked at the very beginning.

Rules that save trouble

• heating on dedicated circuits — a heater permanently connected to its own circuit, not to a socket via an extension lead; an extension lead under a 2 kW heater is the most common winter mistake;
• old aluminium wires and heating — heating is a continuous load, for hours, not momentary like a kettle; a circuit that “somehow tolerated” short peaks will show weaknesses with heating — aluminium connections require inspection, and often circuit replacement;
• heating mats and foils — require RCD and correct sensor installation; this is an electrical installation component, not flooring;
• boiler instead of a geyser — plus several kW; treat it in the balance like a second heater;
• tariff and control — with tariffs with cheaper zones (e.g., G12), automation and contactors allow heating water and accumulating heat when electricity is cheaper; this makes a real difference in bills.

Order: installation first, then heaters

As with a heat pump, the order determines costs: power balance and installation assessment before purchasing appliances avoids a scenario where new heaters are waiting, but circuits still need to be built. In older apartments, a natural solution is often to combine the topic with phased installation replacement — the “kitchen + bathroom + heating circuits” phase completes everything in one go.