Young Blonde Girl In Front Of The Window With Flowers

In the US, the NFRC Window Label lists the following terms:
• Thermal transmittance (U-factor). Best values are around U-0.15 (equal to 0.8 W/m2/K).
• Solar heat gain coefficient (SHGC) (ratio of solar heat (infrared) passing through the glass to incident solar heat)
• Visible transmittance (VT) (ratio of transmitted visible light divided by incident visible light)