28/08/2025
Thinking about upgrading your windows? Understanding a few key features of glass can make a huge difference in comfort, energy efficiency, and even your power bill! Let’s break it down:
🔆 Visible Light Transmittance (VLT)
This measures how much natural light passes through the glass. A lower VLT reduces glare and heat from the sun, but if it’s too low, your room may become too dark—leading to more artificial light use and higher energy costs. Balance is key!
❄️ Thermal Conduction & U-Value
The U-value (Uw) tells you how well the entire window—glass and frame—resists heat flow. The lower the U-value, the better it insulates!
For example:
A single-pane window with a Uw of 6.2 loses heat quickly.
Double glazing with argon gas and thermal break frames can cut that loss in half!
☀️ Solar Heat Gain Coefficient (SHGC)
SHGC measures how much heat from direct sunlight enters through your window. It’s rated between 0 and 1—the lower the number, the less heat gets in.
Keep in mind: The angle of the sun affects actual performance, so orientation and location matter!
🪟 Double Glazing Options & Frame Types
Not all double glazing is the same! Options include:
Gas fills (like argon) for better insulation
Low-E coatings to reflect heat
Warm edge spacers to reduce condensation
And don’t forget frames! uPVC, timber, aluminium, and composite frames all perform differently in terms of durability, insulation, and style.
💡 Not sure what’s best for your home?
Book a FREE Energy Assessment with one of our experts! We’ll help you choose the right glazing and frames to maximize comfort and savings.
