Balancing Heat and Light in European Glass: A Look at the Solar Heat Gain Coefficient (SHGC) with Internorm Glass

As we strive to make our homes more energy-efficient, every design choice counts. One such decision involves the type of glass we choose for our windows. For those living in climates like Canada’s, where winters are harsh but sunlight is plentiful, striking a balance between heat retention and light admission is vital. This blog post explores how European glass, using Internorm as an example, achieves this delicate balance through a scientific measure called the Solar Heat Gain Coefficient (SHGC).

Understanding the Solar Heat Gain Coefficient (SHGC)

The SHGC is a rating that measures how much solar radiation (or heat) a window lets into a building. It is expressed as a number between 0 and 1. The lower the SHGC, the less solar heat the window transmits, and the higher the SHGC, the more heat it allows inside1.

How SHGC Impacts Your Home

A high SHGC can be beneficial in cold climates like Canada’s, where solar heat gain can offset some of the heating costs in winter. However, it’s also essential to consider the potential for overheating during the summer months. Therefore, choosing a window with the right SHGC requires balancing these seasonal needs.

The Internorm Example: Striking the Balance

Internorm, Europe’s leading window brand, has mastered the art of balancing heat and light in its glazing solutions. Let’s explore some data to understand this better.

Take, for example, Internorm’s HF 310 window. This model uses triple-glazed insulation glass and boasts an impressive SHGC of 0.512. With this high SHGC, residents in Canadian homes can take full advantage of the sun’s heat during chilly winters, reducing reliance on artificial heating systems.

However, the HF 310 window also features a low U-value of 0.6 W/(m²K), which indicates excellent thermal insulation3. This means that while the window allows substantial solar heat gain, it also minimizes heat loss from the inside of the home to the outside. This combination results in an energy-efficient window suitable for Canadian climates.

Other Factors to Consider

While SHGC is crucial, it should not be the only factor considered when selecting windows. Other elements, such as U-value (indicating insulation performance), visible transmittance (measuring the amount of visible light admitted), and local climate conditions, should all play a role in the decision-making process.


Choosing the right window glass is a complex task, particularly in regions with diverse seasonal climates like Canada. However, understanding measures like the Solar Heat Gain Coefficient (SHGC) can assist homeowners in making informed decisions. Brands like Internorm provide excellent examples of how to strike a balance between heat and light, offering energy-efficient solutions that cater to varied climatic needs.