The installation of new windows is a moment many homeowners look forward to with great anticipation. This stage determines whether the investment in modern joinery will meet expectations. It is worth remembering that even the best windows from renowned manufacturers can lose their insulating properties if installed improperly. For that reason, the inspection of installation works should not be treated merely as a formality, but rather as a key element of the construction or renovation process. An informed client who knows what to pay attention to can avoid many issues — from heat loss and air leaks to malfunctioning mechanisms.

Checking compliance with the order

The first step in window inspection is ensuring that the installed products match what was stated in the contract and order. It is recommended to have a copy of the documentation on hand to verify elements such as dimensions, profile color, type of glass, opening method, and additional features like micro-ventilation or decorative grilles. While differences may appear minor, in practice they can significantly affect both functionality and appearance. Logistic errors sometimes occur during execution — a quick check of compliance helps catch them immediately and avoid later warranty claims.

Checking geometry and positioning of windows

The next step is to make sure the windows have been installed according to building standards. Geometry plays a crucial role here. By using a level, one can check whether the window frame has been set vertically and horizontally. Permitted deviations are minimal — generally they should not exceed 1.5 mm per meter of length. Excessive tilting may cause improper sealing or eventual warping.

It is also important to check the expansion gap, the space between the frame and the wall. If it is too narrow, it may cause stress and cracking in the frame; if too wide, proper sealing becomes difficult. Professional installers typically maintain a gap of 15 to 25 mm depending on the technology used.

Quality of installation and construction details

Windows must not only be properly aligned but also firmly secured. It’s worth checking whether the team used a sufficient number of anchors, dowels, or fixing screws. Their spacing should comply with both manufacturer guidelines and construction standards to ensure stability of the entire structure.

Another aspect involves sealing materials. Increasingly, the so-called “warm installation” is used, which employs vapor-tight and vapor-permeable tapes along with mounting foam. This method improves thermal insulation and protects against moisture. When inspecting the work, ask the team what materials were used and request to see them.

Checking glass and window frames

Frames and panes are the most visible elements while also being vulnerable to damage during transport and installation. Therefore, carefully inspect the surface of profiles to detect any scratches, chips, or dents. This is especially important for wood-effect or colored finishes where damage is difficult to repair.

Glass should be inspected both up close and from a distance. Minor scratches or dirt may only be noticeable in daylight. A light reflection test can also help — by standing at an angle, imperfections become easier to spot. If the windows have special features such as burglary-resistant or acoustic glazing, check whether the glass has been properly marked.

Hardware mechanisms — handle operation and window functionality

A window is not just its frame and pane but also the mechanisms that determine its usability. During inspection, open and close each sash several times. The handle should operate smoothly, without sticking or resistance. Also test tilt function, micro-ventilation, and handle misplacement lock.

Hardware components are crucial for window tightness and security. Issues such as a loose handle or difficulty closing may indicate improper installation. It is better to report concerns immediately rather than wait for the problem to worsen.

Airtightness and thermal insulation

One of the most important window parameters is airtightness. Even slight leaks can lead to heat loss, drafts, and moisture buildup indoors. As part of the inspection, a simple test can be performed — run your hand along the frame to check for airflow. Another method is to use a candle: if the flame flickers, it signals air penetration.

Professional window installation involves proper sealing with foams, tapes, or special profiles. A correctly mounted window should ensure not just thermal but also acoustic insulation, protecting against outdoor noise.

Collecting documentation and warranty

A thorough inspection covers not only workmanship but also the complete documentation the client should receive. This includes the warranty card, user and maintenance manual, technical certificates, and the handover protocol signed by both parties.

Such documents are critical for any future warranty claims or service. Without them, enforcing your rights can be difficult. Always make sure all papers are handed over and signed on the day of inspection.

Who benefits most from a proper inspection?

Taking an informed approach to window inspection is useful for every client but especially important in the following cases:

• new homeowners who want to ensure their investment in energy-efficient windows brings the expected results,
• people renovating apartments who cannot afford extra repair costs,
• investors and developers for whom work quality impacts property value and the satisfaction of future residents.

In every case, a thorough inspection helps avoid costly issues and improves the comfort of living in the building.

Summary

The inspection of new window installation is not merely a formality but a crucial stage that determines comfort and durability. Checking compliance with the order, geometry, quality of installation, functionality of hardware, airtightness, and documentation completeness are fundamental steps every client should take.

If you want to ensure your windows are installed with the utmost care, contact Fintecnic. Our experts will guide you on what to check during inspection, and our experienced fitters will take care of every detail so you can enjoy comfort and security for many years.