Glass and Glazing for Replacement Windows

The appearance of the glass or glazing in a replacement windows has a major impact on the overall appearance of the windows.

In this section we will consider the main options available to you. These include:

	Glass extras such as Georgian or Leaded lights designs
	Stained Glass or "coloured lights" designs
	Patterned or textured glass designs
	Low E or Pilkington K type glass

Of all the possible "additions" or "extras" you can add on to your replacement windows perhaps Low E glass is one of the least visually "impacting". Because of this we want to, in particular, draw your attention to it. To have replacement windows that perform to the very highest standards then Low E glass is virtually essential. You will also find out even more about it in our Pilkington K Glass section. (Pilkington K is a form of Low E Glass)

Low E or Low Emissivity Glass

Low E glass is a form of glass which when added to double glazing allows you to save even more energy. 

Typically double glazing using Low-E glass has energy conservation properties as good as normal triple glazing but without the 50% increase in weight.

The advantages of using Low-E glass are:

	Better heat insulation
	You save money with reduced heating bills
	Reduced carbon dioxide emissions into the atmosphere
	Reduces condensation on your window frames internally

Installing argon gas within the sealed units instead of air can have even greater energy savings. Argon is an inert gas, which has better thermal properties than dry air. In the UK we express the rate of heat loss in 'U values'. The lower the U value, the greater the thermal insulation and savings on your fuel bill.

Typical U values:

	The U value of single clear glass is 5.4
	With ordinary double glazing this is improved to 2.6
	With Low-E glass the U value is reduced to 1.8
	If argon gas is used to fill the air gap, the U value will reduce to 1.6

Special Note:

Whilst we recognise that replacement windows are still available single glazed we will on this web site concentrate on the double glazed versions only.