Exterior joinery: managing the building's energy performance

Why is exterior joinery a lever for energy performance?

Exterior joinery constitutes a sensitive point in the building envelope . It ensures the transition between interior and exterior, while also contributing to the management of thermal, light and acoustic flows.

In older buildings, they are often responsible for significant heat loss. Replacing them is therefore an effective way to improve overall performance, provided it is integrated into a coherent approach.

High-performance joinery allows for:

• to limit heat loss in winter
• to control solar gain in summer
• to improve acoustic comfort
• to improve airtightness

"High-performance joinery does not compensate for poor insulation, but it optimizes the entire system."

Definition and role of exterior joinery in the building envelope

Exterior joinery encompasses all the elements that ensure the building's enclosure: windows, doors, shutters, and bay windows. It directly contributes to thermal performance , security, and aesthetics.

Their role is multifaceted and cross-cutting in a construction or renovation project.

Thermal and acoustic insulation

Windows and doors contribute to reducing energy loss . The glazing and the performance of the frame directly influence heating and cooling consumption. Good thermal insulation reduces heating and cooling needs, thus guaranteeing energy savings. The glazing and the quality of the frames play a crucial role in this.

Acoustic insulation becomes essential in urban or exposed environments. The choice of glazing and the quality of installation determine the level of comfort.

Security and burglary resistance

Openings are sensitive access points. Securing them relies on:

• multipoint locks
• laminated glazing
• certified systems

These elements are particularly important on the ground floor or in professional premises.

Comfort and brightness

Window and door frames influence natural lighting. The light transmission factor (TLw) and the solar factor (Sw) determine the amount of light and heat entering the building.

Architectural harmony

The materials, colors, and finishes contribute to the building's identity. The joinery must integrate with the existing architectural style.

What are the main types of exterior joinery?

Exterior joinery comes in several families, each with its own technical specifications and performance.

Windows: ventilation, light and insulation

Windows provide natural light , ventilation, and thermal and acoustic insulation for buildings. Their design must meet climatic constraints and the specific needs of the occupants.

The main types of openings

• Swinging or French style: traditional inward opening.
• Tilt and turn: dual function of full opening or tilting for ventilation.
• Sliding: ideal solution for large openings.
• Fixes: optimize the supply of light.

The most common materials

• PVC windows : practical and economical, minimal maintenance.
• Wooden windows: warm and ecological, requires regular maintenance.
• Aluminium windows: Modern and robust, perfect for large spaces. Requires thermal breaks for good insulation.
• Mixed wood-aluminum: high-performance alliance between aesthetics and durability.

The main types of glazing

• Standard double glazing: two glasses separated by argon gas.
• Acoustic double glazing: different thicknesses for sound insulation.
• Triple glazing : three glasses for maximum thermal insulation.
• Laminated glazing: glasses assembled with a PVB film for safety.

Exterior doors: security and insulation

The front door combines security, insulation, and aesthetics. It is available in several versions:

• Materials : Doors made of wood, steel, aluminum, PVC or a wood-aluminum combination…
• Security: multipoint locks (3 to 7 points), armor plating, laminated glass...
• Insulation: thermal break threshold, insulating panels, etc.

Models vary from traditional to contemporary, with solid, glazed or semi-glazed versions.

Shutters: thermal and solar protection

The shutters also provide thermal and solar protection for the building . They enhance insulation in winter and limit overheating in summer.

Main types of shutters

• Swinging shutters: traditional materials (wood, PVC, aluminum), solid or louvered versions, classic style.
• Roller shutters: integrated trunk, possible motorization, good protection and insulation.
• Adjustable sun blinds: adjustable slats to manage light and heat, contemporary design.

Gates: access and security

The gate is the primary element of security and welcome to a property. It demarcates access while affirming the architectural style of the whole.

The main types of opening

• Beaters: classic opening with one or two leaves, generally opening inwards.
• Sliding: side opening along a rail, ideal solution for tight spaces or sloping entrances.

The most common materials

• PVC: economical and easy to maintain, very weather resistant.
• Aluminum: modern, light and stainless, allows for varied designs and large dimensions.
• Wood : warm and natural aesthetic, requires regular maintenance (stain, paint).
• Steel or wrought iron: very robust and secure, offers a traditional or contemporary style, essential anti-corrosion treatment.

Customization and security options

• Filling: full for total blackout, openwork for brightness or semi-full for an aesthetic compromise.
• Motorization: automation for optimal user comfort, with remote control or connected system.
• Access control : integration of intercom, videophone or digital code to secure the entrance.
• Matching gate: creation of a separate pedestrian access, harmonized with the style of the gate.

Bay windows: light and continuity between interior and exterior

Bay windows provide maximum natural light and create visual continuity between the interior and exterior. They must combine aesthetics, thermal comfort, and sound insulation to ensure a pleasant living environment.

Fixed bay windows

• They do not open, which allows for a large glass surface for optimal lighting.
• Thanks to their design, the risks of heat loss are limited.
• They are particularly suitable for areas where you want to promote brightness without needing an opening.

Sliding glass doors

• They promote smooth circulation between the interior and exterior thanks to their lateral opening.
• Their sliding system avoids clutter, ideal for small spaces or terraces.
• They can be equipped with different options (motorization, integrated roller shutters) for greater ease of use.

Thanks to their large glass surfaces and their insulation performance, fixed and sliding bay windows are a preferred choice for optimizing brightness and creating a harmonious link with the outdoors.

How to evaluate the performance of exterior joinery?

Exterior joinery is evaluated according to three essential criteria. Its actual performance depends on the quality of installation and the sealing of the joints.

Thermal insulation

The thermal insulation of a window or door frame is assessed on two levels:

• The glazing alone, characterized by the coefficient Ug : double glazing with argon reaches Ug ≈ 1,1 W/m²K, triple glazing reaches Ug ≈ 0,5 W/m²K.
• The entire window (frame + glazing + spacer), characterized by the coefficient Uw : the common values ​​are Uw ≤ 1,3 W/m²K, or Uw ≤ 1,0 W/m²K for the passive building.

Doors are characterized by their thermal transmittance coefficient Ud (in W/m²K). The lower this value, the higher the insulation performance. Roller shutters or hinged shutters enhance insulation: a PVC or aluminum shutter reduces heat loss by 5 to 15%, while a shutter with insulated slats achieves a 20% reduction.

Soundproofing

Sound insulation is measured in decibels (dB). An Rw value of 30-32 dB is suitable for quiet environments. In urban areas or near roads, glazing must achieve an Rw value of ≥ 40 dB . Near airports or railways, an Rw value of ≥ 45 dB is required.

Asymmetrical glazing ( 6-16-4) attenuates certain frequencies, while acoustic laminated glazing (44.2) provides more uniform insulation. ACOTHERM certification (AC1 to AC4) guarantees a sound reduction of 28 to 40 dB, provided that the installation is carried out carefully and with appropriate seals.

Weather resistance (AEV classification)

This classification evaluates the resistance of the carpentry according to three criteria:

• Air permeability (A): scale from 1 (poor) to 4 (excellent),
• Watertightness (E): scale from 1 (low) to 9 (high exposure),
• Wind resistance (V): scale from 1 to 5 (pressure) and A to C (deformation).

These laboratory tests allow for the selection of window and door frames suited to their exposure. Windy or humid areas require high ratings (e.g., A4 E9A V4C) to guarantee long-term weatherproofing.

Safety and standards

The safety of joinery is based on several certifications and standards.

Certification of locks

The A2P certification assesses the resistance of locks to burglary. It offers different levels of protection, with particular attention paid to main access points and sensitive areas of a building.

Certification of glazing

Cekal certification guarantees the quality and performance of different types of glazing:

• Insulating glass, attesting to their thermal and acoustic performance,
• Laminated glazing, evaluated for their safety, durability and sound attenuation properties,
• Tempered glass, certified according to their specific usage.

European standards

Two European standards govern the safety of joinery: 

• EN 356: defines the levels of protection of glazing, with classes ranging from P1A to P8B (from burglar-resistant to bulletproof).
• EN 1627: joinery resistance standards (RC1 to RC6).

When and why should you replace your windows and doors during an energy renovation project?

Replacing windows and doors is usually part of a comprehensive renovation strategy. It must be coordinated with other work.

Typical situations:

• single glazing
• air infiltration
• thermal discomfort
• noise

The correct order of work consists of:

• treat the insulation
• then replace the joinery
• adjust the ventilation

Poor coordination can lead to problems, particularly those related to humidity.

What architectural and regulatory constraints govern exterior joinery?

Exterior joinery shapes the architectural appearance of a building . It must comply with the urban planning regulations defined by the Local Urban Development Plan (PLU ). Modern materials offer numerous customization possibilities thanks to their finishes and colors.

Finishes according to materials

• Le  wood comes in natural finishes with stain or in paint shades.
• Le PVC offers different colors and wood imitations, suitable for traditional constructions.
• L'aluminum material stands out for its thermo-lacquered, textured or matte finishes, with two-tone option.
• Mixed joinery wood-aluminum combine the warmth of wood inside and the strength of aluminum on the facade.

The entrance doors incorporate decorative glazing and two-tone finishes, harmonizing with classic and contemporary architecture.

Urban planning constraints

The integration of joinery is subject to regulatory constraints. The Local Urban Development Plan may impose specific colours and materials, prohibit certain components such as PVC, or require adherence to the original proportions.

In protected areas, particularly near historical monuments, modifications require the approval of the Architect of the Buildings of France . This regulation preserves heritage by favoring traditional solutions, such as the use of wood.

What innovations are transforming exterior joinery?

Home automation and eco-design are transforming the joinery sector, combining improved comfort and respect for the environment.

Home automation and connected joinery

The joinery is integrated into the building's intelligent systems:

• Motorized roller shutters become automated : night programming, gradual awakening, or even adaptation to the weather via sensors.
• The windows incorporate innovative technologies : photovoltaic cells for electricity production, electrochromic glasses regulating brightness and heat.
• Security is enhanced by connected functions : remote control by smartphone, break-in detection, biometric recognition, etc.

Smart windows

• electrochromic glazing
• photovoltaic integration

Eco-design and performance

The sector is developing eco-friendly solutions . Wood, certified by FSC or PEFC, benefits from natural treatments for its durability. PVC incorporates up to 70% recycled material in its profiles, while aluminum reaches 95% recyclability.

Glazing also shows significant progress. New-generation triple glazing achieves a Ug value ≤ 0,6 W/m²K thanks to rare gases and warm edge spacers. Phase-change films represent a major innovation, storing daytime heat and releasing it at night.

Exterior joinery plays a crucial role in a building's energy performance and comfort. Its selection and implementation must be part of a comprehensive approach, integrating the building envelope, ventilation, and energy systems to ensure sustainable and consistent results.

Exterior joinery solutions are supported by an ecosystem of industrialists, manufacturers and specialized networks , who are constantly innovating to meet the requirements of energy performance, sustainability and comfort, in a context of profound transformation of the building sector.

Text written and documented by batipole.com, a media outlet for professionals in the building, housing and real estate sectors.