For medium-to-large sized existing commercial buildings, secondary glazing systems can achieve about the same performance as replacing windows with new high-performance models, but for about half the cost. These products attach to the interior side of existing windows, improving occupant comfort, health and wellness, while significantly reducing energy costs. Secondary glazing systems are professionally installed and far less expensive and disruptive to occupants than undergoing a full window replacement.

Secondary glazing systems are a high-performance window solution that modernizes an existing building and improves tenant comfort. They work by creating an insulating pocket of air between the windows that significantly reduces air leakage, outdoor air infiltration and heat transfer. A low-e coating provides additional benefit by allowing daylight through, while reducing unwanted exterior heat gain and interior heat loss. This results in fewer drafts, reduced outside noise and glare, reduced HVAC load (which can result in a reduction to necessary heating and cooling equipment), and significant energy savings.

Many owners and property managers are wary of occupant disruption during a window upgrade project. However, secondary glazing systems can be installed much faster than a complete window replacement, and during any season. And since the secondary window is attached to the inside of an existing window, there’s no need for scaffolding—buildings can often be retrofitted during or after normal operating hours to maximize tenant productivity. Additionally, these window systems can match existing window aesthetic, so the only difference tenants will notice is the improvement to sound, temperature and visual comfort.

After completing pre-installation measurements, installers attach secondary glazing systems to the existing primary window and then tightly seal the new frame and the secondary window. The upgraded window remains accessible for periodic cleaning and maintenance.

Secondary glazing system window attachments can be custom-ordered directly from your preferred manufacturer listed below. These manufacturers will visit your property to measure and mock-up a sample product to find the right fit for your building.

• Wausau Window & Wall Systems
• Thermolite
• RENOVATE by Berkowitz