Energy efficiency and sound insulation are certainly important criteria when choosing new windows. However, if you live in a detached house, on the ground floor or in a dark mezzanine, the first thought before you go to sleep is: "Is my home safe?"
Today, the European Union has established strict, measurable standards - the EN 1627 standard - that classify windows and doors according to exactly how long they can resist an actual attack. These are the Resistance Classes (RC), ranging from RC1 to RC6.
Before we analyse the categories, we need to understand the psychology of burglary. Police research proves that the average burglar wants to enter quickly and silently. If a door or window resists for more than 3 to 5 minutes, the risk of noise and detection increases dramatically.
In 90% of cases, if the door resists for more than 5 minutes, the burglar gives up and moves on to the next, easier target. The RC categories measure exactly this: the guaranteed minutes of resistance under continuous attack with specific tools.
Modern anti-burglary technology doesn't just aim to "hold out" - it also aims to deter. A high-class RC mechanism is visible - the burglar recognises that the risk isn't worth it and moves on.
RC1 - the burglar uses only physical force (kicks, shoulder pushes). RC1 windows do not protect ground floors or easily accessible balconies, as they yield quickly even with a simple screwdriver.
The most recommended category for the average home. It resists at least 3 minutes of continuous forced attack with simple hand tools (screwdrivers, pliers, wedges). The mechanism features reinforced mushroom cams and a keyed or Secustik handle.
The RC2 N class is identical in mechanisms but does not require anti-vandal glass. Ideal for upper floors, where the burglar cannot easily reach the glazing but will attempt the hardware.
Upgrading to RC2 typically costs €80–150 more per window compared to basic mushroom cams. A small investment that buys 3 minutes of security - and, in practice, peace of mind.
If you live in an isolated detached house, a dark ground floor without grilles, or a high-crime area, RC3 is the right choice.
The professional burglar uses a heavy pry bar, a second screwdriver and a small hammer. RC3 resists at least 5 minutes of continuous, hard attack with these tools.
In the RC3 category, Triplex/Laminated P5A safety glass is mandatory - a multi-layered pane that withstands multiple impacts without allowing a human body to pass through.
The distance between locking points in RC3 is much shorter compared to RC2. The metal alloy is harder, the perimeter mechanism thicker - essentially impossible to bend with a pry bar.
💡 RC4, RC5, RC6: Power tools, cutting discs, bullet-proof glass - 10 to 20 minutes of resistance. Intended exclusively for banks, jewellers and military installations.
For a window to receive RC2 or RC3 certification, a single factor is not enough. Three prerequisites must be met simultaneously. If even one is missing, the certification is void.
The frame and perimeter mechanism must be manufactured specifically for the corresponding RC class. Stronger alloys, thicker mushroom cams, reinforced security keeps.
The glass cannot be standard - otherwise the burglar smashes it and climbs through. It must be certified anti-vandal glass (P4A for RC2, P5A for RC3).
An RC3 window fixed only with PU foam is not RC3. A pry bar can tear the entire frame off the wall! Heavy-duty screws at specific intervals are required.
💡 Tip: When requesting quotes for new aluminium windows, don't ask vague questions. Ask for the RC class in writing (e.g. RC2) that the windows meet, together with the corresponding certificate number.
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