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How Heat, and Light can Penetrate Windows

By July 21, 2023September 28th, 2023No Comments

Light Penetration

Windows serve as gateways to the outside world, connecting us to the natural elements. They allow us to enjoy the beauty of sunlight and the warmth it brings. However, have you ever wondered how various elements, like heat, light, UVA, and UVB, interact with windows? In this blog, we’ll explore the science behind how these elements can penetrate windows and the measures we can take to protect ourselves from their potentially harmful effects.

  1. Heat and Light Penetration

When sunlight hits a window, three main interactions occur, absorption, reflection, and transmission.

Absorption: Some of the sunlight’s energy is absorbed by the window glass, which causes the glass to warm up.

Reflection: A portion of the sunlight is reflected into the atmosphere.

Transmission: The remaining light passes through the window, entering the interior space.

Single-glazed windows have relatively poor insulation and may allow more heat to enter a room. Modern double or triple-glazed windows often incorporate Low-E (low emissivity) coatings, which reduce heat transfer and help maintain comfortable indoor temperatures.

  1. UVA and UVB Penetration

Ultraviolet (UV) radiation is a part of the electromagnetic spectrum that we cannot see, but it has significant effects on our health and the environment. There are two main types of UV radiation, UVA and UVB.

UVA radiation is the longer wavelength of the two and can penetrate glass windows with ease. It’s linked to skin aging and can contribute to skin cancer development over time.

UVB radiation is shorter in wavelength and has slightly higher energy. While it’s partially absorbed by most window glass, a significant portion can still penetrate indoors. UVB radiation is the main cause of sunburn and is also associated with skin cancer.

  1. Protecting Against Harmful UV Radiation

Exposure to UV radiation, both indoors and outdoors, can pose health risks. Here are some measures to protect yourself from UVA and UVB radiation:

  1. Window Accessories: Install window accessories, such as solar shades, blinds, or curtains, that are designed to block UV radiation. Integral blinds can be included within the cavity of the glazed unit, which can be raised, lowered or tilted to adjust light penetration.
  2. UV-Filtering Window Films: Applying UV-filtering films to windows can significantly reduce the amount of UVA and UVB radiation that enters your home. These films are transparent and block harmful rays. Alternatively laminated glass can incorporate this film within the glazed unit. This also helps reduce the bleaching of furniture and floor coverings cause by UV rays.
  3. Window Tints: Tinting windows can help reduce the amount of heat and light entering a room, consequently lowering the impact of UV radiation.
  4. Seek Shade: When indoors, stay away from direct sunlight coming through windows, especially during peak sun hours.

Understanding how heat, light, UVA, and UVB interact with windows is crucial for protecting ourselves and maintaining a comfortable living environment. While windows can provide us with a connection to the outside world, they also expose us to various elements that can impact our health. By using appropriate window treatments, films, and tints, and taking protective measures, we can strike a balance between enjoying natural light and safeguarding ourselves from the harmful effects of UV radiation.