What is thermal deflection?

Thermal deflection is a rare, natural phenomenon that can occur when sunlight reflects off of a surface with enough heat to distort siding or other materials. The damage can be to one’s own residence, or to a nearby home.

How does it happen?

A combination of various factors needs to be in place for the thermal deflection phenomenon to occur, including some or all of the following:

  • Certain times of year and sunlight angles
  • Close proximity of home exterior walls
  • Structure design
  • Surfaces such as window glass, roof shingles, asphalt or swimming pools that could reflect sunlight
  • Heat radiating from nearby surfaces such as driveways, air conditioning compressors and barbeque grills
  • Lack of trees and shrubs, fences and cloud cover to divert sunlight

Are the products involved in thermal deflection defective or were they improperly installed?

No, a thermal deflection incident does not necessarily indicate that product performance or installation were improper. The natural phenomenon instead indicates the presence of some or all of the above factors.

What can I do to avoid, or stop, thermal deflection?

Unfortunately, it is difficult or even impossible to predict if thermal deflection is going to occur in any particular situation. Nevertheless, to minimize your risk you can:

  • Use full screens in your windows
  • Use trees and shrubs to block or diffuse the sun’s rays

What do I do if it happens?

The homeowner should contact their insurance company, and see if it is covered by their policy.

For more detail, you can refer to the study sponsored by the U.S. government and conducted by Ernest Orlando Lawrence Berkeley National Laboratory or the research by Cardinal IG (glass manufacturer).

What is thermal deflection?

Thermal deflection is a rare, natural phenomenon that can occur when sunlight reflects off of a surface with enough heat to distort siding or other materials. The damage can be to one’s own residence, or to a nearby home.

How does it happen?

A combination of various factors needs to be in place for the thermal deflection phenomenon to occur, including some or all of the following:

  • Certain times of year and sunlight angles
  • Close proximity of home exterior walls
  • Structure design
  • Surfaces such as window glass, roof shingles, asphalt or swimming pools that could reflect sunlight
  • Heat radiating from nearby surfaces such as driveways, air conditioning compressors and barbeque grills
  • Lack of trees and shrubs, fences and cloud cover to divert sunlight

Are the products involved in thermal deflection defective or were they improperly installed?

No, a thermal deflection incident does not necessarily indicate that product performance or installation were improper. The natural phenomenon instead indicates the presence of some or all of the above factors.

What can I do to avoid, or stop, thermal deflection?

Unfortunately, it is difficult or even impossible to predict if thermal deflection is going to occur in any particular situation. Nevertheless, to minimize your risk you can:

  • Use full screens in your windows
  • Use trees and shrubs to block or diffuse the sun’s rays

What do I do if it happens?

The homeowner should contact their insurance company, and see if it is covered by their policy.

For more detail, you can refer to the study sponsored by the U.S. government and conducted by Ernest Orlando Lawrence Berkeley National Laboratory or the research by Cardinal IG (glass manufacturer).