Glass glossary

Glass glossary

This is where we let you into our glaziers’ secret code…

What is the U-value of glass?

The U-value of glass indicates how effective the glass in a window will be at stopping you losing heat in the winter and cool in the summer. The lower the U-value number, the better the insulating performance of the glass.

What is SHGC?

SHGC stands for solar heat gain coefficient. It’s a number representing how well the glass blocks the heat from the sun. The lower the number, the better the window is at shading the inside of the building.

What is a bevel?

A bevel is a sloping edge on a glass panel. You see bevelling most commonly in mirrors. The bevel is measured in terms of the width of the bevel. You don’t want to confuse a bevel with a polished edge (see below).

What is  FPAE (flat polished all edges)

FPAE stands for flat-polished all edges — all edges have been polished down to make them smooth, so they’re safe to be used on things like table tops.

What is an IGU or double glazed unit?

An IGU is an insulated glass unit. It consists of two or more panes of glass separated by an air space. (It’s usually two panes, hence the more common term, double glazing.) The space between the pains is filled with argon gas because it increases the unit’s ability to cut down the temperature transfer between indoors and outdoors. IGU units are great for that and also for keeping noise down.

What is low-e glass?

The light you can see coming through your window is only part of it. There’s also ultraviolet light (which causes furnishings and carpets to fade) and infrared light (which is the warm part). Low-e glass cuts down on some of the light you can’t see without blocking any of the visible light.