Problem addressed

According to the US Department of Energy, about 30% of a home’s energy is lost through windows. However fully replacing windows can be expensive with high embodied carbon.

Solution overview

Window Insulation has a low emissivity coating which can be applied to existing windows providing proven energy savings and improved occupant well-being. The window insulation solution is a simple coating that can be applied onto existing glass and to any window type, shape or style. The technology of this solution is similar to a low-e coating, but it can be retrofitted rather than applied during glazing manufacture and performs better than some factory applied coatings. Retrofitting windows with this coating rather than a low-e film has a variety of benefits, including that it is twice as durable, does not contribute to fire risk, and can be applied seamlessly.

The insulating coating reduces the transmission of heat into homes in the summer, reducing the temperatures during the warmer months while not affecting the amount of light passing through the windows. During the winter, the coating traps heat indoors by blocking certain wavelengths of the electromagnetic spectrum. This results in less energy needed to heat homes in the winter. The solution does reduce g-factor (from approximately 0.85 to 0.68 for a single glaze window) and therefore solar gains in winter, but it also significantly increases the retention of paid heat.

According to information supplied by Window Insulation, the benefits of this energy-saving alternative to costly window replacements include:

  • U-value improvement of existing glass – testing done by Nottingham Trent University proved a reduction in U-value of a window by 1.09W/m2K, from 2.63W/m2k to 1.54 W/m2k . The solution is most effective on lower performance windows but can have smaller impacts on better performing windows. A recent study at Liverpool John Moore’s University shows that when the coating is applied to a modern window, the u-value improved from 1.2 W/m²K to 1.1 W/m²K.
  • 20-40% thermal resistance improvement, reducing energy use
  • Blocks 99% of damaging Ultraviolet & 83% Infrared light
  • 50% reduction in condensation, reducing mould growth
  • Minimal impact on visible light transmission
  • Reduction in overheating

The window insulation results in increased occupant well-being, healthier working environments, reduced risk of skin and eye damage, and reduced damage to furnishings. The solution is proven to be maintenance free for 20 years and causes no significant change to window appearance.

The solution is scalable via a drop shipping product distribution model enabling access to large volumes of material, however this does increase the transport emissions associated with the material.

Case study

The Window Insulation coating has been successfully installed in over 37 countries over the past 20 years.

Facts and Figures

1-2 yrs
1.09 W/m2K
10 Yr
20-30 %

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