When it comes to window lingo, there are plenty of values and acronyms that appear on a label and actually paint a great picture of that window’s future performance. The issue is, if you don’t know what you’re looking for, you risk making a sub-par purchase.
The U-Value is something you should look out for, as it is the ‘overall heat transfer coefficient’, meaning that it measures how well the window will transfer heat. The higher the value, the worse the thermal performance. Low U-Value Windows have properties that boast high levels of insulation.
When determining a U-Value, the airflow around the window and the emissivity of the glass must be taken into account. The emissivity means it can absorb certain types of energy and then radiate said energy through itself and into a home. The lower the emissivity of the glass, the lower the rate of heat loss there will be and in turn, the lower the U-Value rating.