When shopping for new windows, you have probably come across the term U-value. But what does it really mean, and why do you need to pay attention to it?
What Is U-Value?
U-value (also known as thermal transmittance) measures how well a window or building material conducts heat. It tells you how much heat passes through the material- the lower the U-value, the better the insulation.
In short:
- Lower U-value = better energy efficiency
- Higher U-value = more heat escapes through the window
U-value is measured in W/m²·K (watts per square meter per degree Kelvin), but you don’t need to memorize the units, just remember that lower is better.
Why Is U-Value Important for Windows?
Your windows are one of the main sources of heat loss in your home. Choosing windows with a low U-value offers several benefits:
- Energy Savings: Low U-value windows reduce heat loss in winter and heat gain in summer. That means your HVAC system does not have to work as hard, leading to lower energy bills.
- Comfort: Improved insulation keeps indoor temperatures more consistent, eliminating cold drafts near windows during the winter.
- Environmental Impact: Better-insulated windows reduce energy consumption, which helps lower your carbon footprint.
- Increased Home Value: Energy-efficient features are a strong selling point for potential home buyers. Windows with low U-values signal a well-insulated, modern home.
Where to Find the U-Value of Your Windows
You can usually find the U-value of your windows in one of these places:
- Manufacturer’s Label: New windows often have an energy performance label from organizations like ENERGY STAR® or the National Fenestration Rating Council (NFRC). The U-value will be clearly listed there.
- Window Frame or Glass Etching: In some cases, the U-value or a reference code is etched into the glass or printed on a sticker along the window frame.
Energy Star Symbol
Sample
Bottom Line:
If you're upgrading your windows, pay close attention to the U-value. It's a simple number that can make a big difference in your comfort, energy bills, and overall home efficiency.
Need help finding windows with the right U-value? Contact our team- we’re here to help you start on your window project!