What is the best glazing for my home? – Part 1
Affinity R&D Team
Up to 40% of a home’s heating energy is lost through the windows and up to 87% of heat gained is through them.
As Australians become more environmentally conscious, reducing daily energy consumption has become more of a priority for homeowners.
Improving the performance of windows, can reduce energy costs and greenhouse gas emissions.
Around 99% of the sun’s rays are in the form of visible light, UV rays and infrared rays (heat) and are collectively referred to as radiant energy.
In this article I will explain how the performance of glazing is measured and what makes glazing energy efficient for windows and doors in Perth homes.
What is the Solar Heat Gain Coefficient, or SGHC?
Arguably the most important measure of energy efficiency is ‘SGHC’ or Solar Heat Gain Coefficient. This is the amount of heat radiation transmitted through the glass from direct exposure to sunlight.
SHGC is expressed as a number between 0 and 1, where 0 means no solar heat transmission.
In winter, glazing with a higher SHGC will keep you warmer as it allows the winter sun’s heat in, however in summer a lower SHGC will keep you cooler.
The climate in which you build your home has a big impact on what amount of SHGC will create an energy-efficient home.
What is visible transmission?
Visible transmission is how much natural light passes through the glazing.
This is more for aesthetic reasons as some coatings on glass can reduce the amount of natural light.
Untreated glass such as single pane or double glazing has very high visible transmission.
What is a u-value?
This refers to the heat conductivity of the glazing together with the frame.
For example, an aluminium frame has much higher conductivity than a timber one which affects indirect heat transmission.
When looking at the full window product, the u-value will affect energy efficiency.
What is the best glass for my home?
There are many options for Perth homeowners when choosing glass.
Stay tuned for Part 2 next week, where I will compare low-e glass and double-glazing.