U Values For Doors And Windows

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.

U values for doors and windows.

How is u value determined. U value is an inverse measure. We can advise on how you might achieve the required standard. 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.

To comply with building regulations windows like every other element of your property must meet a certain minimum u value. A u value calculated by us should be sufficient to satisfy the requirements of building regulations. Window energy ratings provide a simplified method of understanding the energy saving properties of a window. This calculated value conforms with bs en iso 10077 part 1.

For most energy efficient windows the whole window u factor is higher than the center of glass u factor. U factor u value range between 20 to 1 20. 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. The lower the u factor the better insulated the window.

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. 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. In the case of a window it s 1 6 w m2k. Improved education and awareness of the cost of heating and cooling that escapes from poorly insulated components and glass panes have led to window and door manufacturers developing energy efficient windows and doors typically labeled r5 u 2 meaning the glass is the most energy efficient possible at a 5 rating and the window or door with all of it s built out components are a 2 which is almost as low as any rating can go remember a 5 is the highest energy rating for r value which is.

A higher u factor allows heat to escape. Our u value calculator is a whole window calculator designed to calculate an accurate u value of windows and doors. This is desirable in very hot and sunny locations to avoid the greenhouse effect inside a home.