Winter–Summer Window Adjustment: What Does “Winter Mode” Really Mean?

The phrases “window winter mode” and “winter–summer window adjustment” usually refer to changing how firmly the sash compresses the gasket. Some hardware systems allow this compression to be adjusted, but that does not mean every window has a universal “summer/winter” switch or needs to be changed twice a year.

The important point is to identify the actual hardware system and the cause of the problem. If the window is airtight, closes correctly and the handle operates without excessive resistance, a change of season alone is not a reason to adjust it. If a draught appears, the handle becomes difficult to operate or the sash rubs against the frame, the first step is to establish what actually needs correction.

What does “winter mode” mean on a window?

“Winter mode” is a widely used term for seasonal sash-to-frame compression adjustment in hardware systems that allow it. Technically, it means adjusting the elements responsible for locking the sash and pressing it against the gasket. Depending on the design, these may be adjustable rollers, locking cams, locking pins or other hardware components that control compression.

There is no single universal “winter position” shared by all manufacturers. Hardware systems differ in their adjustment mechanisms, ranges, markings and tools. For that reason, generic advice to rotate every eccentric element in one particular direction may be wrong for the hardware installed in a specific window.

Does every window have winter–summer adjustment?

No. Whether sash compression can be adjusted depends primarily on the installed hardware system and its configuration. It cannot be determined reliably from the age of the window or the appearance of the profile alone.

Many hardware systems include components with adjustable compression, but the adjustment method is not universal. “Winter mode” is therefore best understood as a commonly used term for seasonal compression adjustment rather than one standardized setting shared by all PVC windows.

How can I check whether my window has adjustable compression?

Open the sash, inspect the hardware around its perimeter and look for the manufacturer's markings. Windows may use systems from manufacturers such as Roto, Winkhaus, MACO or SIEGENIA, but the manufacturer's name alone does not determine the adjustment method — the specific hardware system and installed components matter.

The most reliable approach is to check the manufacturer's instructions for the identified system. Do not assume that the direction of rotation, marker position or required tool is the same for every window. If a component does not move without force or its function is unclear, it is better not to alter the setting by trial and error.

When does increasing compression make sense?

Adjusting compression can make sense when a draught is felt between the sash and frame and the specific hardware system allows the components that control compression to be adjusted. However, insufficient compression is only one possible cause of a draught.

Before making an adjustment, check whether the sash closes correctly, does not rub against the frame, the handle operates normally and the gasket has no obvious damage. Correct compression should support even contact between the sash and gasket, not compensate for unrelated defects.

When should you not increase compression?

The sash rubs against the frame. This indicates that the sash geometry and relevant hardware settings should be checked. Increasing compression does not correct the cause of rubbing.

The handle requires significant force. Increasing compression further may make closing even more difficult. First determine whether the resistance comes from hardware adjustment, sash geometry or another problem.

The gasket is cracked, permanently deformed or has lost elasticity. Its condition should be assessed before deciding whether the problem requires an adjustment or gasket replacement.

The draught is felt at the joint between the frame and the wall. In that case the cause may lie outside the sash itself, and changing sash compression will not solve it.

The installed hardware system is unknown. Randomly turning locking components is not a reliable diagnostic method. First establish which elements are designed to be adjusted.

How can compression be adjusted without risking damage to the hardware?

There is no single safe instruction such as “turn all eccentrics in the same direction” that applies to every window. A safer sequence is:

— identify the hardware manufacturer and system,
— check the adjustment instructions for that specific system,
— identify which components control compression,
— remember or mark the original position,
— make changes only within the range specified by the manufacturer,
— after the change, check handle operation and whether the sash closes correctly around its entire perimeter.

If the adjustment point cannot be moved as described in the manufacturer's instructions, requires excessive force or the window operates worse after the change, stop further attempts. In that situation it is safer to have the window checked as part of a professional window adjustment.

Do windows need to be adjusted twice a year?

There is no need to automatically change every window setting in autumn and spring. If the window works correctly throughout the year, there are no signs of leakage, the sash does not rub and the handle operates smoothly, adjustment based only on the calendar is unnecessary.

As with other hardware settings, adjustment should be performed when there is a specific reason. We discuss this in more detail in our guide on how often windows should be adjusted.

How do you seal windows for winter if compression adjustment does not help?

If the window still lets air through after compression has been checked, the next step is to identify where the leak is coming from.

A draught between the sash and frame may be related to hardware settings, sash geometry or the condition of the gasket. If air is felt around the outer edge of the frame, the source of the leak may be the frame-to-wall joint. If the sash rubs against the frame, its geometry should be checked rather than simply selecting a “stronger mode”.

We explain how to distinguish these situations in more detail in our guide to a draught from a window and choosing the appropriate repair.

What about balcony doors?

The same principle applies to balcony doors: if the installed hardware system allows compression adjustment, it can be carried out in accordance with the documentation for that system. Because the sash is larger and heavier, correct geometry and hardware setup are particularly important.

If a balcony door starts rubbing, requires substantial force to close or the handle becomes difficult to operate, stronger compression should not be assumed to be the solution. First establish whether the issue concerns compression, sash geometry or another component.

What is worth checking before the heating season?

Before winter, briefly check the condition of the gaskets, the operation of the handle and hardware, sash closing and any areas where air leakage can be felt. Only when the specific hardware system allows compression adjustment and there is a reason for it should changing the setting be considered.

We cover the complete seasonal inspection, including hardware maintenance and other checks, separately in our guide to window service before winter.

When is it better to leave adjustment to a technician?

It is worth leaving the adjustment to a technician when the hardware system cannot be identified, the sash rubs against the frame, the handle operates with significant resistance, hardware components are damaged or the draught remains despite checking compression and the gasket. In such cases the solution may involve sash geometry adjustment or a broader window repair rather than compression alone.

The scope of work is matched to the actual cause of the problem. The initial diagnosis and technician's visit are free of charge, and the cost of the required work is explained before the repair begins.

Summary: not every window needs a “winter mode”

“Winter mode” is a convenient common term for compression adjustment, but it does not refer to one setting shared by all windows. Whether and how compression can be adjusted depends on the specific hardware system. If a window works correctly, its settings do not need to be changed simply because winter is approaching. If a draught or closing problem appears, identify the cause first and adjust the appropriate component only afterwards.

If the question is about frequency rather than season

A change of season does not itself determine when a window should be adjusted. If you want to know when it is actually worth returning to the window settings and which symptoms justify a check, see our guide to how often windows should be adjusted. It separates the calendar from the actual condition of the window and helps avoid adjusting a correctly functioning window “just in case”.