U-Values Explained
A U value is a measure of heat loss in a building element, in our case used to determine the performance of our Upvc Windows and Doors. It can also be referred to as an ‘overall heat transfer co-efficient’ and measures how well parts of a Window transfer heat. This means that the higher the U value the worse the thermal performance of the Window or Door. A low U value usually indicates high levels of insulation. They are useful as it is a way of predicting the composite behaviour of an entire Window System rather than relying on the properties of individual materials, such as the glass component of a window, common practice in Australian window and door industry.
U-Value examples
Nu-Eco – Eurocell Typical Energy Efficient uPVC Window – Double Glazed (Report Below)
Glazing ID Cooling Star Heating Stars Cool % Heat % Uw
4/20AR/4LE mm 
73% 70% 1.6
WERS Generic Standard Industry Typical Aluminium Window – Double Glazed
Glazing ID Cooling Star Heating Stars Cool % Heat % Uw
3/6/3 mm Glass 
23% 27% 5.3
WERS Generic Standard Industry Typical Timber Window – Double Glazed
Glazing ID Cooling Star Heating Stars Cool % Heat % Uw
3/6/3 mm Glass 
38% 47% 3.3
WERS Generic Standard Industry Typical Aluminium Window – Single Glazed
Glazing ID Cooling Star Heating Stars Cool % Heat % Uw
3mm Glass None None 2% 0% 7.3
WERS Generic Standard Industry Typical Timber Window – Single Glazed
Glazing ID Cooling Star Heating Stars Cool % Heat % Uw
3mm Glass 20% 24% 5.5
