Aluminum Door and Window Selection Guide

Selecting aluminum doors and windows should not be based solely on the profile brand, color, or frame depth.

The correct system should be selected by evaluating the following criteria together:

• intended use of the building,

• opening dimensions,

• building height,

• facade orientation,

• wind and rain exposure,

• thermal and acoustic performance targets,

• glazing specifications,

• opening type,

• sash weight,

• frequency of use,

• security requirements,

• water drainage system,

• installation conditions.

Therefore, the main question when selecting aluminum joinery should not be “Which profile is better?” but rather “Which system provides the required performance for this project?”

For different aluminum joinery solutions, see Optimal Mimarlık – Aluminum Door and Window Systems.

What Should Be Defined First When Selecting Aluminum Doors and Windows?

The first step is not choosing a product. It is defining the required performance.

The following project data should be established:

• interior or exterior use,

• window or door function,

• width and height of the opening,

• fixed or operable sash requirements,

• facade orientation,

• building height,

• wind load,

• rain exposure,

• thermal-insulation target,

• acoustic requirements,

• security level,

• frequency of use,

• accessibility,

• maintenance conditions.

A residential window, a high-rise office window, a retail entrance door, and a factory administration-building window should not be selected according to the same criteria.

How Should an Aluminum Profile System Be Selected?

Profile selection should not be based only on the series name or frame depth.

The main criteria include:

• frame and sash geometry,

• aluminum wall thickness,

• profile stiffness,

• thermal-break width,

• glazing capacity,

• gasket configuration,

• hardware compatibility,

• corner joints,

• drainage chambers,

• water-discharge channels,

• maximum system dimensions,

• surface finish.

Profile stiffness becomes particularly important in large openings.

As sash dimensions increase, so do:

• glass weight,

• profile deflection,

• hinge or roller loads,

• operating forces.

Maximum dimensions stated in system catalogues should therefore always be evaluated together with actual project conditions.

What Is a Thermally Insulated Aluminum Window?

Aluminum has high thermal conductivity.

In thermally insulated aluminum systems, the internal and external aluminum sections are separated by a low-conductivity thermal break.

The thermal break reduces heat transfer through the profile.

However, good thermal performance does not depend on the thermal break alone.

Overall performance is determined by the combination of:

• frame profile,

• glazing,

• glass-edge zone,

• gaskets,

• insulating-glass spacer,

• frame-to-wall junction.

What Do Uf, Ug and Uw Mean?

These three values must be distinguished when evaluating aluminum windows.

Uf – Frame Thermal Transmittance:
The thermal transmittance of the frame or profile system. In Turkish technical terminology, this corresponds to çerçeve veya profil sisteminin ısı geçirgenlik katsayısı.

Ug – Glass Thermal Transmittance:
The thermal transmittance of the glass or insulating glass unit. In Turkish, cam ünitesinin ısı geçirgenlik katsayısı.

Uw – Window Thermal Transmittance:
The overall thermal transmittance of the complete window, including glazing, frame and glass-edge zones. In Turkish, pencerenin toplam ısı geçirgenlik katsayısı.

The U-value expresses the heat transfer through a building component per unit area. Lower values indicate better thermal insulation.

For this reason, a window should not be evaluated solely by the Ug value of the glass.

The correct comparison should be based primarily on Uw – overall window thermal transmittance.

Thermal-performance calculations for windows and doors commonly refer to:

ISO – International Organization for Standardization / Uluslararası Standardizasyon Örgütü

ISO 10077-1 – Thermal Performance of Windows, Doors and Shutters: Simplified Calculation Method

ISO 10077-2 – Thermal Performance of Frames: Numerical Calculation Method

How Should Glass Be Selected for Aluminum Joinery?

Glass is an integral part of the aluminum system.

The following should be evaluated together:

• thermal insulation,

• solar control,

• visible-light transmission,

• safety,

• acoustic performance,

• glass dimensions,

• total sash weight.

Depending on project requirements, combinations may include:

• Low-E – Low Emissivity glass / düşük yayınımlı ısı kontrol camı,

• Solar Low-E – Solar Control Low Emissivity glass / güneş kontrollü düşük yayınımlı cam,

• solar-control glass,

• tempered safety glass,

• laminated safety glass,

• acoustic laminated glass.

In large and heavy sashes, glass weight directly affects profile and hardware selection.

How Should the Opening Type Be Selected?

The opening configuration affects both usability and technical performance.

Common options include:

• fixed glazing,

• side-hung,

• tilt-and-turn,

• top-hung,

• pivot,

• sliding,

• lift-and-slide,

• folding systems.

Selection should consider:

• available interior space,

• opening dimensions,

• ventilation requirements,

• sash weight,

• frequency of use,

• accessibility,

• security,

• maintenance.

When Should Sliding Systems Be Preferred?

Sliding systems are particularly suitable for wide openings where inward or outward sash movement is not desired.

However, sliding systems should not be selected only for appearance.

The following should be evaluated together:

• rail configuration,

• roller capacity,

• sash weight,

• threshold height,

• water drainage,

• air and water performance,

• locking system.

Lift-and-slide systems provide controlled operation for large and heavy glazed sashes.

For available solutions, see Optimal Mimarlık – Aluminum Sliding Window Systems.

Why Is Air Permeability Important?

Air permeability indicates how much air passes through a closed window or door under pressure differences.

Performance is affected by:

• gasket geometry,

• locking points,

• sash adjustment,

• profile stiffness,

• corner joints.

Air permeability is classified according to:

EN – European Standard / Avrupa Standardı

EN 12207 – Windows and Doors – Air Permeability – Classification

In Turkish:

Pencereler ve kapılar – Hava geçirgenliği – Sınıflandırma

Technical specifications should define the required performance class rather than simply stating that the window must be “airtight.”

Water Tightness and Water Drainage Are Not the Same Thing

One of the most important technical issues in aluminum doors and windows is water management.

The objective of a correctly designed system is not necessarily to prevent every drop of water from entering the external drainage zone.

Under wind-driven rain, a certain amount of water may pass:

• the outer gasket line,

• operable sash joints,

• external profile cavities

and reach the controlled drainage chamber.

The key requirement is that this water must be collected and discharged back to the exterior without reaching the interior dry zone.

Therefore, water tightness and water drainage are related, but they are not the same concept.

How Does Water Drainage Work in Aluminum Windows and Doors?

Modern aluminum systems generally manage water through:

• external gasket lines,

• collection channels,

• pressure-equalization chambers,

• internal drainage channels,

• drainage holes,

• weep-hole covers,

• threshold drainage,

• external sill and water-discharge details.

Water entering the controlled drainage zone is directed into designated profile chambers.

It is then discharged to the exterior through drainage channels and weep holes.

For the system to function correctly, the drainage route must be:

continuous + adequately sized + correctly positioned + open to the exterior

Why Is Pressure Equalization Important?

Wind creates pressure differences between the exterior and interior sides of a window.

This pressure difference may drive rainwater through joints.

In properly designed systems, drainage chambers and profile cavities help equalize pressure with the exterior.

This reduces the pressure driving water inward and allows water within the drainage chamber to discharge by gravity.

Pressure equalization and drainage become particularly important in:

• high-rise buildings,

• highly exposed facades,

• locations subject to heavy rainfall,

• large-format window and door systems.

How Should Drainage Holes Be Designed?

It is not enough for drainage holes simply to exist.

They must be:

• provided in the number specified by the system manufacturer,

• located at the correct points,

• adequately sized,

• connected to the internal drainage path,

• open to the exterior.

Drainage routes must not be blocked during fabrication or installation.

Common causes of blockage include:

• silicone,

• sealant,

• polyurethane foam,

• plaster,

• facade cladding,

• paint,

• mortar,

• construction debris.

A tested system can lose its designed water performance on site if its drainage routes are blocked.

Common Water-Drainage Problems

Many leakage problems are caused not by the basic profile design but by interruption of the drainage system.

Missing Drainage Holes

If the required drainage holes are not machined during fabrication, water cannot leave the profile chamber.

Drainage Openings Blocked During Installation

Sealant, plaster or external finishes can obstruct the drainage outlet.

Interrupted Internal Drainage Channels

Corner joints, hardware screws or incorrect fabrication can interrupt the drainage route.

Incorrect Threshold Levels

This is particularly critical in sliding and lift-and-slide systems.

If the external floor or terrace level is higher than the drainage outlet, water discharge may be prevented.

Incorrect External Sill Detailing

Water discharged from the window can be redirected back toward the system if the external sill is incorrectly designed.

Incorrect or Missing Weep-Hole Covers

Some systems use special external covers to reduce wind pressure at drainage outlets.

Incorrect installation can reduce water performance under wind-driven rain.

Incorrect Frame Level

Drainage systems generally rely on gravity.

If horizontal profiles are installed with incorrect levels or reverse falls, water may collect away from the drainage outlets.

What Is EN 12208?

EN 12208 – Windows and Doors – Watertightness – Classification

Turkish explanation:

Pencereler ve kapılar – Su sızdırmazlığı – Sınıflandırma

This standard classifies the water-tightness performance of windows and doors under rain and pressure conditions.

EN 12208 – Windows and Doors – Watertightness Classification

EN 12208 is a classification standard.

It defines the performance class achieved by the tested product.

What Is EN 1027?

EN 1027 – Windows and Doors – Watertightness – Test Method

Turkish explanation:

Pencereler ve kapılar – Su sızdırmazlığı – Deney yöntemi

EN 1027 – Windows and Doors – Watertightness Test Method

The standard defines how the water-tightness performance of a complete window or door specimen is tested under controlled laboratory conditions.

During the test:

• water is sprayed onto the external surface,

• increasing air-pressure differences are applied,

• the system is monitored for water penetration into areas that must remain dry.

Water that reaches a designated drainage zone and is subsequently discharged through the designed drainage route does not in itself represent failure, provided it does not enter areas that are required to remain dry.

This is an important principle because it confirms that controlled water drainage is an intentional part of modern window-system design.

What Is the Difference Between EN 12208 and EN 1027?

In simple terms:

EN 1027: defines how water tightness is tested.

EN 12208: defines how the test result is classified.

A technical specification should therefore state the required performance class rather than merely stating compliance with EN 12208.

Water Drainage Is Not Only a Profile Detail

An excellent internal profile drainage system is not sufficient if the building junction is incorrect.

Water management must be coordinated with:

• frame-to-wall connections,

• external facade finishes,

• window sills,

• drip edges,

• terrace and balcony levels,

• thresholds,

• channel drains,

• facade waterproofing.

For example, a stone sill installed in front of a drainage outlet may block a correctly designed drainage system.

For this reason, window drainage and building waterproofing must be designed together.

How Should Wind Resistance Be Selected?

As building height increases, windows and doors are subjected to greater wind pressure and suction.

Wind performance depends on:

• profile section,

• profile moment of inertia,

• window dimensions,

• sash dimensions,

• glass thickness,

• fixing intervals.

Resistance to wind load is classified according to:

EN 12210 – Windows and Doors – Resistance to Wind Load – Classification

Turkish explanation:

Pencereler ve kapılar – Rüzgâr yüküne dayanım – Sınıflandırma

EN 12210 – Resistance to Wind Load

What Is the Main Product Standard for Aluminum Windows and Doors?

The main product standard for windows and external pedestrian doors is:

EN 14351-1 – Windows and Doors – Product Standard, Performance Characteristics

Turkish explanation:

Pencereler ve kapılar – Ürün standardı ve performans özellikleri

EN 14351-1 – Windows and External Pedestrian Doorsets

The standard provides the framework for assessing relevant performance characteristics of:

• windows,

• external pedestrian doors,

• fixed elements,

• operable elements.

In Türkiye, the corresponding standards may be published as:

TS EN – Turkish Standard adopting a European Standard / Avrupa Standardının Türk Standardı olarak kabul edilmiş karşılığı

The current status of applicable standards should be verified through the TSE – Turkish Standards Institution / Türk Standardları Enstitüsü.

TSE – Turkish Standards Institution

How Should Gaskets Be Selected?

Gaskets are key components of:

• air tightness,

• water tightness,

• sash compression,

• vibration control.

A correct gasket should:

• have geometry compatible with the system,

• retain adequate elasticity,

• remain continuous,

• have correctly formed corner joints.

Gasket performance depends not only on material quality but also on sash and profile geometry.

How Should Hardware Be Selected?

Hinges, locks, espagnolette systems, handles, stays and sliding rollers must be selected according to sash dimensions and weight.

Selection criteria include:

• sash weight,

• sash height,

• sash width,

• frequency of use,

• security,

• opening type.

Window and door hardware is covered by the:

EN 13126 series – Building Hardware – Hardware for Windows and Door-Height Windows

Turkish explanation:

Pencere ve kapı donanımlarının performans ve deney kriterlerini kapsayan Avrupa standart serisi

What Should Be Considered for Large Sashes?

Large glazed sashes create wide, uninterrupted transparent surfaces.

However, increasing sash size also increases:

• glass weight,

• profile deformation,

• hinge loads,

• roller loads,

• operating forces,

• sensitivity of air and water sealing.

Profile, glazing and hardware capacity must therefore be checked together.

The maximum dimension shown in a catalogue should not be treated as the only design criterion.

When Should Flush or Low Thresholds Be Used?

Flush and low thresholds provide advantages in terms of:

• accessibility,

• visual continuity between interior and exterior,

• architectural appearance.

However, for doors directly exposed to the exterior, the following must be designed together:

• rain exposure,

• external floor level,

• internal profile drainage,

• terrace or balcony slope,

• linear channel drainage,

• facade orientation,

• wind exposure.

Before specifying a flush threshold, the required EN 12208 watertightness classification should be checked.

How Should Security Performance Be Defined?

Security does not depend only on the lock.

The complete system includes:

• profile,

• hardware,

• locking points,

• glazing,

• glazing beads,

• frame fixings.

Where resistance to burglary is required, reference may be made to:

EN 1627 – Pedestrian Doorsets, Windows, Curtain Walling, Grilles and Shutters – Burglar Resistance – Requirements and Classification

Turkish explanation:

Yaya kapıları, pencereler, giydirme cepheler, ızgaralar ve kepenkler – Hırsızlığa karşı direnç – Gereklilikler ve sınıflandırma

EN 1627 – Burglar Resistance

How Should Fire-Resistant Aluminum Joinery Be Selected?

Fire-resistant aluminum doors and windows are tested complete systems and differ from conventional aluminum joinery.

The system is evaluated as a complete assembly of:

• special aluminum profiles,

• fire-resistant insulation inserts,

• fire-resistant glass,

• seals,

• hardware,

• fixings,

• installation details.

One of the principal standards is:

EN 16034 – Pedestrian Doorsets, Industrial, Commercial, Garage Doors and Openable Windows – Fire Resisting and/or Smoke Control Characteristics

Turkish explanation:

Yaya kapıları, endüstriyel ve ticari kapılar, garaj kapıları ve açılabilir pencereler – Yangına dayanım ve/veya duman kontrol özellikleri

For project-specific solutions, see Optimal Mimarlık – Fire Resistant Aluminum Joinery Systems.

How Is Acoustic Performance Achieved?

Acoustic performance does not depend only on glass thickness.

The total sound-insulation performance is affected by:

• glazing configuration,

• laminated acoustic interlayers,

• frame system,

• gasket arrangement,

• sash compression,

• installation gaps,

• frame-to-wall junctions.

Where high acoustic performance is required, the complete window or door assembly should be evaluated rather than the glass alone.

What Should an Aluminum Window and Door Specification Include?

A proper technical specification should define at least:

• system type,

• profile series,

• thermal break,

• surface finish,

• glazing configuration,

• Uf – frame thermal-transmittance target,

• Ug – glass thermal-transmittance target,

• Uw – complete-window thermal-transmittance target,

• air-permeability class,

• water-tightness class,

• wind-resistance class,

• drainage and water-discharge principles,

• hardware type,

• security requirement,

• opening type,

• gasket system,

• installation and sealing details.

A brand name alone is not an adequate technical specification.

Aluminum Window and Door Performance Standards

The current TS EN – Turkish Standard adoption of European Standards and their validity should be checked through TSE – Turkish Standards Institution.

Recommended Decision Sequence for Selecting Aluminum Doors and Windows

The correct selection process generally follows this order:

1. Define the intended use of the building.

2. Determine opening dimensions and actual site conditions.

3. Evaluate facade orientation and building height.

4. Determine wind and rain exposure.

5. Define thermal-insulation targets.

6. Define acoustic requirements.

7. Select the opening type.

8. Determine the glazing configuration.

9. Select the profile system.

10. Verify hardware capacity.

11. Define air, water and wind-performance classes.

12. Evaluate water-drainage and discharge design.

13. Resolve thresholds, sills and external floor levels.

14. Define security requirements.

15. Resolve installation and building-junction details.

16. Prepare the technical specification.

17. Verify fabrication dimensions on site.

Optimal Mimarlık Aluminum Door and Window Systems

Optimal Mimarlık does not evaluate aluminum joinery solely through the selected profile series.

The correct system is created by resolving:

profile + glass + gaskets + hardware + surface finish + water drainage + installation + building junctions

as a coordinated whole.

Thermally insulated windows and doors, sliding systems, concealed-sash systems, large-opening solutions and specialist aluminum joinery should be selected according to the actual requirements of the building and project.

Optimal Mimarlık – Aluminum Door and Window Systems

Optimal Mimarlık – Aluminum Sliding Window Systems

Quick Answers

How should an aluminum window be selected?

Opening dimensions, building height, wind, rain, thermal performance, acoustics, glazing, opening type, drainage and frequency of use should be evaluated together.

What does Uw mean?

Uw – Window Thermal Transmittance means the overall thermal-transmittance value of the complete window, including glass, frame and glass-edge effects.

What does Uf mean?

Uf – Frame Thermal Transmittance means the thermal-transmittance value of the window frame or profile system.

What does Ug mean?

Ug – Glass Thermal Transmittance means the thermal-transmittance value of the glass or insulating glass unit.

Why do aluminum windows have drainage holes?

Drainage holes discharge water that reaches the controlled drainage chamber back to the exterior. If the openings are blocked, water may accumulate inside the system and eventually reach the interior.

Is water entering the profile always a defect?

No. Water entering a designated drainage chamber can be part of the intended system operation. The defect occurs when water reaches areas that are required to remain dry or cannot be discharged correctly.

What is EN 1027?

EN 1027 – Windows and Doors – Watertightness – Test Method defines how window and door water performance is tested under controlled water spray and air pressure.

What is EN 12208?

EN 12208 – Windows and Doors – Watertightness – Classification defines the performance classification achieved in water-tightness testing.

Is drainage important in flush-threshold systems?

Yes. Profile drainage, external floor slope, linear drainage channels, threshold detailing and wind-driven rain exposure must be designed together.

What is the best aluminum window system?

There is no single best system. The correct system is the one that satisfies the required thermal, air, water, wind, acoustic, security and operational performance for the specific project.

Technical Editor and Content Review:
Mehmet Beşe Polatkan, Architect (YTU)

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