The key advantage of vacuum insulated glass is its extremely low thermal transmittance.
The lower the U-value, the better the insulation and energy savings.
But one question is rarely asked: how long will that U-value last?
- U-Value Degradation Is Real For Vacuum Insulated Glass
Test data makes this clear:
For vacuum glass using the same silver-paste sealing process:
- With an evacuation port: U-value = 0.42 W/㎡·K
- Without an evacuation port: U-value ≈ 0.6 W/㎡·K
The difference is about 43%. Water vapor released by organic materials during sealing cannot escape, reducing the vacuum level.
And that is only the difference at the factory. As organic materials continue to decompose and water vapor accumulates, the U-value may continue to rise over time.
- Vacuum Level Is the Lifeline of Thermal Performance
Vacuum glass insulates by using the vacuum cavity to suppress heat conduction and convection.
The higher the vacuum level, the better the insulation. As the vacuum level drops, thermal performance declines.
Any factor that increases gas inside the vacuum cavity can undermine thermal performance:
- CO₂ and H₂O released by the decomposition of organic materials
- Gas ingress through microcracks in the edge-seal joint
- Seal failure caused by corrosion of the joint
- SuperVIG®: VIG Designed for Long and Stable Service Life
The SuperVIG® all-metal sealing process protects long-term vacuum stability in three ways:
① No organic residue, eliminating gas release at the source;
② A strong metallurgical bond with no microcracks, blocking gas ingress;
③ Corrosion-resistant, silver-free solder, maintaining long-term joint integrity and seal reliability.
Together, these three safeguards help keep the U-value of SuperVIG® vacuum glass stable throughout its service life.
The U-value at delivery remains stable 10 years later. That is an insulating window worth investing in.
