Our u value calculator is a whole window calculator designed to calculate an accurate u value of windows and doors.
U values for doors and windows.
This is desirable in very hot and sunny locations to avoid the greenhouse effect inside a home.
We can advise on how you might achieve the required standard.
To comply with building regulations windows like every other element of your property must meet a certain minimum u value.
How is u value determined.
Window energy ratings provide a simplified method of understanding the energy saving properties of a window.
U factor u value range between 20 to 1 20.
According to part l1a of current building regulations a domestic window installation should achieve a u value no higher than 1 4 w m k.
Typical u values on windows and window energy ratings are similar to the familiar energy labels you see on home appliances rated from a the lowest up to g the highest or worst performing.
Thus a single paned window with a basic aluminum frame has a u value above 1 usually around 1 25 while triple pane windows may have u values around 25 or lower.
This calculated value conforms with bs en iso 10077 part 1.
High performance double pane windows can have u factors of 0 30 or lower while some triple pane windows can achieve u factors as low as 0 15.
Double glazed windows filled with argon are typically 1 4 w m2k while thicker triple glazed windows can go as low as 0 7 w m2k.
For most energy efficient windows the whole window u factor is higher than the center of glass u factor.
U value is an inverse measure.
The lower the u factor the better insulated the window.
A higher u factor allows heat to escape.
Typically double glazed windows record a u value of between 1 2 w m k and 3 7 w m k while triple glazed windows are usually rated below 1 w m k.
In the case of a window it s 1 6 w m2k.
Some window performance figures are expressed with a u value and others with a window energy rating although the latter has been adopted as the more commonly used.