Windows are the building component through which heat loss, noise and draughts are felt most clearly. Window fitters replace windows and external doors, adapt the junctions and fit the hardware. The quality of the result depends less on the window itself than on the installation: a very good window with a poor seal at the junction is worse than an average one with a proper seal.
They take measurements, remove the old windows, fit the new ones, create an airtight, driving-rainproof seal to the wall, install window sills and adjust the hardware. This also includes external doors, balcony doors and lift-and-slide doors, as well as disposal of the old units, which in older buildings may be contaminated with hazardous substances.
For a standard window of around 100 × 120 cm, the guide price is about CHF 800 to 1'500 per unit depending on the frame material, according to our Renovation Costs guide. Large units and lift-and-slide doors cost significantly more. Scaffolding, adjustments to reveals and blinds, and painting work after installation are not included.
uPVC is the cheapest and low-maintenance, timber-aluminium combines an attractive interior look with a weather-resistant outer shell and sits at the top end of the price range, while timber needs regular maintenance and is mainly suitable where the local streetscape requires it. In protected and core zones, the material may be prescribed. Clarify this before requesting quotes, otherwise you will be comparing variants that are not permitted at all.
In noisy locations, replacing windows is the single most effective measure against noise. What matters is the glazing build-up and the tightness of the junction, not simply the number of panes. State what external noise you are exposed to when requesting quotes, so the contractor can offer the right glazing build-up instead of fitting standard glazing.
Ask for an itemised list for each window with dimensions, opening type, material and glazing build-up instead of a single lump-sum price. Check whether removal, disposal, internal and external sealing, window sills and adjustment of the blinds are included. Clarify who will handle the painting of the reveals after installation; this is the most common omission.
New windows are airtight; old ones were not. The unintended air exchange through leaky windows disappears, and the moisture from cooking, showering and breathing stays in the room. Without changing your ventilation habits or installing a mechanical ventilation system, mould often appears for the first time after window replacement. Plan for this instead of discovering it later.