Why energy saving windows require vacuum insulating glass

Energy Efficient windows

Windows &Doors account 25-30% of overall building envelope. Since the thermal performance of door and window glass is much lower than that of wall insulation materials, composite insulated glass are usually used to increase the structural design (thickness) to improve the thermal performance of the door and window system.

Composite Insulating glass consist of two or three pieces of single glass are bonded to the frame made of aluminum alloy,warm edge,TPS,4SG etc. Sealed with primary butyl and structure silicone sealant.The IGU is sealed unit to keep windows low thermal conductivity. Inert gas are also used to reduce thermal convection to improve thermal insulation performance.

Thermal break aluminium windows is becoming thick and heavy to get better energy efficiency

Thermal break aluminium windows is becoming thick and heavy to get better energy efficiency

Methods to increase windows performance

Cold and severe cold regions have high thermal insulation requirements. The latest standard in Beijing stipulates that the U value of doors and windows is limited to less than 1.1.

The Low-E insulating glass U value are 1.6-1.8W/M2.K, After installed in thermal break aluminium windows,window  value is 2.0-2.5.

In order to further decrease U value,window&door manufacturers make every efforts:

  • Optimizing the design and configuration of main and auxiliary materials,such as increasing the thermal break nylon thickness ,increasing aluminum profile cavities, and adopting new materials, etc.;
  • Increasingglass thickness, from double glazed units to triple glass units and more low-E coatings are applied.

However, the continuous increasing glass will lead to stronger aluminium frame and stronger hardware and the overall cost will also increase significantly.


Aluminium ingot price in China -2021-2022

Aluminium ingot price in China -2021-2022

Float glass price from 2020-2022-China float glass price

Float glass price from 2020-2022-China float glass price

Especially affected by the rising prices of bulk commodities such as aluminum and float glass, which brings huge costs increasing to most door and window enterprises. Therefore, it has become an industry consensus to improve the glass performance , reduce the overall thickness of glass, and save the windows frame materials .Vacuum insulating glass began to be widely accepted by the market.

Why vacuum glazing windows?

  • The vacuum insulating glass products can reach 0.47W/M2.K combining with advanced double silver low-E coating, Even if making it into insulated glass, the overall thickness is similar to normal IGU. the energy-saving requirements of doors and windows can be met without existing main and auxiliary windows materials.
  • Aluminum alloy, aluminum clad wood, plastic steel, glass fiber polyurethane and other profile materials can be matched with vacuum insulating glass . After optimizing, its cost is much lower than the current equivalent performance doors and windows even if VIG glass price is higher than triple glass.
Passive house windows with vacuum insulating glass

Passive house windows with vacuum insulating glass


Beside above advantages,HaanGlas vacuum insulating glass has below advantages:

1.No evacuation holes

HaanGlas vacuum insulating glass are sealed under high vacuum degree condition,surface mechanical strength is well protected and decrease VIG spontaneous breakage ratio ,and VIG failure caused by bad sealing.

2.Low temperature metal edge sealing technology.

Normal VIG will be sealed with glass solders in 350℃ which will cause tempered glass anneal,and cause uneven surface strength.Our low temperature metal edge sealing won’t cause glass anneal,after testing data such as leakage rate, energy saving performance, welding strength, etc can ensure up to 25 years lifetime.

  1. Even glass strength.

All HaanGlas vacuum insulating glass are tempered with Glaston TC series tempering furnace,Maximum strength reach 210Mpa,and flatness can be controlled within 1%.

  1. Ultra thin thickness.

HaanGlas can produce minimum 6.3mm vacuum insulating glass,and can be adopted in building renovation without changing original frame and structure.With 0.47W/M2.K ,the historical buildings energy consumption can be well controlled.

HaanGlas is your turnkey vacuum glass manufacturer and solution provider,kindly contact us for your next great building.