Increasing Need for Energy Efficiency Spurs Demand for Windows and Doors

Windows and doors – demand for which hit $27.6 billion in the US in 2018 – are an integral part of any home or commercial structure. They enable entry and egress, provide access to light and air, and, in many cases, can improve the exterior appearance of a property.

Beyond these functions, construction professionals and consumers understand that windows and doors also play a crucial role in improving the energy efficiency of a building.

ENERGY STAR Standards are a Key Element in Minimizing Energy Consumption

Traditionally, windows and doors have served as the main culprits in building energy loss, as their frames would allow warm or cool air to escape, while their glazing could allow sunlight to create uncomfortably warm interiors – a particularly important consideration for much of the southern half of the US.

In response to this, the US Department of Energy – in conjunction with manufacturers and other industry participants – developed the ENERGY STAR program, which established minimum standards for energy efficiency. ENERGY STAR standards are based on local climate conditions, ergo:

• ENERGY STAR-compliant windows and doors designed for use in the northern half of the US must prevent heat loss
• Windows and doors used in the southern half of the US must minimize solar heat gain while maximizing visible light transmission

ENERGY STAR-Compliant Products Dominate the Residential Market

The ENERGY STAR program has proven incredibly popular among manufacturers, contractors, and consumers – especially homeowners. ENERGY STAR-compliant products accounted for about 80% of residential windows, entry door, and patio door demand in 2018 and will continue to dominate these market segments going forward. Windows and doors that meet ENERGY STAR criteria often include such features as:

• Glazing units with multiple panes of glass, providing superior insulation compared to single-pane glazing
• Low-emissivity (low-e) coatings that deflect sunlight while keeping warm air in the home
• Gas-filled glazing that forms insulating window barriers
• Aluminum or vinyl cladding (for wood windows) that reduces air leakage around the frame

Entry and patio doors that are compliant with ENERGY STAR guidelines often have:

• Insulated foam cores to minimize heat transfer
• Glazing units with multiple panes of gas, low-e coatings, and gas-filled barriers
• High-performance weatherstripping to minimize air leakage

Commercial Products Also Espousing Energy Efficiency

While commercial windows and doors are not included in the ENERGY STAR program, manufacturers of these products have also worked to improve their energy efficiency – so much so that such innovations like glass-filled multiplane glazing and low-e compounds are common in the US. However, given the prevalence of metal products – which are highly susceptible to heat loss – in commercial structures, it can be difficult to achieve similarly high levels of energy savings.

In addition to glazings, coatings, and insulated foam cores, commercial window and door manufacturers have adopted other features to boost their products’ energy efficiency. These include:

• Spacers that insulate frame components and keep panes separate, minimizing expansion and contraction in extreme temperature conditions
• Smart glass that controls the amount of natural light that can be let into a structure
• Insulated window and door frames to further minimize heat loss

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About the Author:

Matt Zielenski is a Senior Analyst at The Freedonia Group, where he covers trends in the use of building materials and related construction products in the US market.