How vacuum glass prevent window condensation

Winter is coming, do you often encounter a problem -window condensation?

Door and window condensation is the condensation of dew on the window indoor surface. While vacuum glass can help you get rid of this problem permanently.

When the surface temperature of the solid (glass, window sash, window frame) is lower than the dew point of the surrounding moisture, the water vapor in the air becomes liquid water, which condenses on the cold solid surface, and condensation will occur.

When the dew is severe or cannot evaporate quickly, water droplets will form and flow down glass edge. There is less condensation on the sunny side, and more condensation on the kitchen and bathroom on the north side.

Condensation happens on glass roof and windows in winter,water fall from the glass

Condensation happens on glass roof and windows in winter,water fall from the glass

Reasons causing window condensation

  1. High temperature difference between indoor and outdoor

The temperature of indoor air is higher than the surface temperature of condensation objects (glass, window sash, window frame),meanwhile the glass surface temperature is lower than the dew point.That’s also the reason why window condensation always happens in winter.

condensation happens in winter when the indoor glass surface is lower than indoor air

condensation happens in winter when the indoor glass surface is lower than indoor air

When the glass surface temperature is lower than the dew point of the surrounding moist air, the water vapor changes to liquid water, and then condenses on cold inner glass surface, and condensation occurs.

The large temperature difference between indoor and outdoor actually brings challenge to the insulation performance of doors and windows, so reducing the temperature difference between indoor and outdoor can solve the problem, but we cannot control the outdoor temperature, and the indoor temperature cannot be lowered because of heating requirement. Increasing the indoor glass surface temperature is the right solution.

  1. High indoor humidity

Activities such as washing and showering, cooking, breathing, and planting green plants will increase indoor air humidity. If the humidity cannot be removed through well ventilation, the indoor humidity exceeds the saturated humidity in the air, and the moisture form water on glass.

Humidifier also increase the humidity and moisture in house

Humidifier also increase the humidity and moisture in house

  1. Large area windows &doors

When decorating, many people prefer large windows and doors to get better visual effect and good lighting,  However, large transparent windows& doors will inevitably lead to the problem of excessive condensation in cold areas,because the glass is the weakest point of building with the worst thermal insulation performance.

If the thermal insulation performance of large area windows is poor,condensation will make you crazy in winter

If the thermal insulation performance of large area windows is poor,condensation will make you crazy in winter

How vacuum glass prevent window condensation?

With above analysis,the solution for window condensation is to increase the indoor glass surface temperature and keep ventilation.

The biggest advantage of vacuum glass is extreme thermal insulation performance.

Vacuum insulating glass U value is less than 10% of monolithic glass,and also 25% of most widely used double glass units with high low-E coating performance,below chart shows the typical U value of common glass used in windows & doors.

Typical Glass Combination6mm 6+1.52+6 6-12A-6 6 LE -12A-6 6LE-12A-6LE-12A-6 5+0.3V +5
Glass TypeTemperedLaminatedDouble glass unitDouble glass unitTriple glass unitVacuum glass
Glass thickness6MM13.52MM24MM24MM42MM10.3MM
Glass weight 15 kgs/sqm30 kgs/sqm30 kgs/sqm30 kgs/sqm45 kgs/sqm25 kgs/sqm
Glass U value5.8 w/m2.k5.2 w/m2.k2.7 w/m2.k1.6 w/m2.k0.6 w/m2.k0.47 w/m2.k

In the cold winter, even if the outdoor temperature drops to -30°C, the temperature of the indoor glass surface is close to room temperature and much higher than the condensation temperature.

Before delivery,every piece vacuum insulating glass will be tested, the exterior piece will be exposed in -80℃ for 3 minutes,and inner piece won’t have condensation ,so customers can trust our every piece glass even if in the polar areas.

The thickness of vacuum laminated glass is just 16.82mm,which is 30% thiner than insulated glass

The thickness of vacuum laminated glass is just 16.82mm,which is 30% thiner than insulated glass

With ultimate thin and light,vacuum glass can also fit the most simple windows profiles and replace your current glass without changing the whole window system.

Even if the window has poor thermal property,excellent VIG also helps avoid condensation as glass account 80% of windows and is the key point.

Other measures to prevent window condensation

Because vacuum glass price is high,even if HaanGlas developed vacuum glass with much better price than others,the costs to replace your current all windows is not cheap,then how to avoid condensation without extra expense?


  1. Keep ventilation.

Properly opening windows every day for ventilation can reduce the air humidity and remove the moisture generated during the day’s activities.,It can also ensure that the indoor air is fresh and healthy.The same dew on the glass can also be air-dried normally.

Keep ventilation will help create fresh and healthy living environment

Keep ventilation will help create fresh and healthy living environment

In the space equipped with exhaust fan, the exhaust fan can be opened appropriately to reduce or eliminate the problem of condensation.


  1. Keep wipe the glass.

If you feel cold when window is opening , you must often wipe off the dew on the glass to prevent water from forming on the window sill.

Check more tips to get rid of window condensation:

Haanglas manufacture and supply vacuum glass ,contact us for your next green building.