How composite windows and doors can boost energy efficiency

As part of the tenth annual World Green Building Week, which took place in September 2019, the World Green Building Council (WorldGBC) issued a bold vision for how buildings around the world can reach 40 per cent less embodied carbon emissions by 2030. To meet this goal, changes need to be implemented throughout a building’s infrastructure. Here, Gert De Roover, Buildings Segment Manager, explains why composite materials contribute to the drive for greener buildings.

According to WorldGBC, buildings and construction are responsible for 39 per cent of global energy-related carbon emissions. Out of this, 28 per cent come from the operational “in use” phase to heat, power and cool buildings while eleven per cent of these emissions are attributed to embodied carbons — the carbon released during construction and material manufacturing. But no matter where these carbon emissions come from, the sector must tackle energy inefficiency across the entire building lifecycle. A way of improving building efficiency is to evaluate where energy is wasted. One area that contributes to a large portion of wasted energy is through a building’s entry and exit points, or its windows and doors.

Keep in heat in

On average, around 30 per cent of a building’s heat escapes through its windows alone. During colder months, the efforts of a building’s heating system can be in vain as much of the expense and energy to keep the building at a desirable temperature goes to waste.

Unlike metal, fiberglass composite materials are effective thermal insulators, making them the ideal candidate for window and door frames. Typically, insulation in an aluminium window frame is referred to as a thermal break — the continuous barrier between the inside and outside window frames that prevents thermal energy loss. While effective, this insulation method requires thicker frames, which can alter the desired appearance of windows. The insulating properties of composite materials such as fiberglass mean that there is no need for a thermal break, as the material is capable of ensuring thermal efficiency alone.

Built to last

When a wooden frame faces changes in moisture and humidity, it risks warping, swelling, or contracting. This could impact the condition and operation of the window or door, and create draught space for warm air to escape and cold air to leak out. Repeated exposure to moisture may even cause rot. Unlike wood, fiberglass doesn’t expand or contract when exposed to wet or humid conditions, and it does not rot, meaning it can last longer and work effectively in any environmental conditions.

While another common window frame and door material, polyvinyl chloride (PVC), does not swell or warp like wood, it presents its own challenges. PVC can be easily misshapen, so metal inserts are sandwiched between the exterior and interior frames of the window to match wood’s structural stiffness. However, the problem arises when the seal binding these elements together isn’t maintained — stopping it from keeping the elements out and the heat in. These inserts create complexity, and complexity can create costs. Fiberglass window frames do not require structural inserts, as the stiff material is manufactured in a single profile.

Combining forces

From a materials performance perspective, fiberglass offers several benefits over traditional materials. First it has the stiffness and strength without the need for adding stiffeners, and this simplifies the manufacturing process. Secondly, fiberglass is resistant to thermal expansion, corrosion and rot. This means less maintenance over the lifespan of the window or door frame. Thirdly, fiberglass frames are a great insulator helping to retain heat or cooling to help save energy.

No matter where you use composites, the benefits of the material will greatly impact the efficiency of windows and doors. With our engineering and manufacturing experience, we produce cost-competitive window and door profiles that meet both your desired aesthetic and which help save costs across the window’s lifetime.

In order to improve sustainability, homeowners and construction companies will have to take a number of measures to reduce unnecessary energy loss. Windows and doors may be a necessary feature in any home, but the wasted energy that escapes out of them is anything but needed. To tackle lost energy and improve efficiency, composite materials for windows and doors are an advantageous option.