Window tints: Darker shades for cooler cabins?

• Darker tints do not mean cooler cabin
• Heat rejection quality depends on TSER and IRR index
• Dark tints may impair night-time visibility.

In May 2019, Transport Minister YB Anthony Loke announced that dark tints for rear windows are now legal for private vehicles. This was a welcomed move by the public as they claim it provides better hot weather protection and added security.

The latest regulations permit the front windscreen to have 70% Visible Light Transmission level (VLT), front windows at 50% VLT while the rear windows and windscreen at any VLT. For the uninformed, the lower the VLT, the darker shade the tints are.

We agree that darker tints do mean outsiders will have more difficulty peeping into the car, giving a better peace of mind to your belongings and passengers. However, dark tints may reduce night-time visibility which may be a concern for those with poorer vision.

Darker tints, however, does not immediately equate to a more cooling cabin. How effective the heat rejection depends entirely on the quality of the tints used – their Total solar energy rejected (TSER) and infrared rejection (IRR) index. The higher the TSER and IRR index, the more effective it is at keeping your cabin cool.

Be wary on tinting film stores trying to “upsell” you to tints with lower VLT as darker does not necessarily mean better heat rejection. Poor quality tints with low TSER and IRR index may make your car even warmer as black absorbs heat and the tints are not able to disperse heat as efficiently as high-quality tints.

On the contrary, tints with high VLT (clearer tints) can also achieve the same cabin cooling effects provided it has high TSER and IRR index.