In the depths of winter a major concern for homeowners is keeping their home warm, without spending an absolute fortune on heating bills. The additional desire to reduce excessive use of fossil fuels in heating the home is also a factor with everyone who is environmentally aware glass lean to extension.
For homeowners adding an extra room has meant a proportionate increase in their heating bills and consumption of fossil fuels.
However this does not have to be the case, provided that an extension is properly specified.
The greatest advances in product performance in the construction industry recently has been in the performance of glass, specifically in what are known as IGU (insulated glass units).
When I first became involved in the construction industry over 20 years ago most windows and conservatories were constructed using framework, either timber or uPVC, glazed with single panes of glass. Then double glazing was introduced, which simply doubled the insulation performance of the glass. This was a big step forward in heat retention. However, in percentage terms, the step from single thickness glass to double glazed units is not as great as the effects of the latest technology coatings that can be applied to the glass, prior to manufacturing the IGU.
To put some figures to this, the following are the u values of a 4mm single pane of glass, a simple sealed unit double glazed with two sheets of 4mm glass and an air filled 20mm cavity, finally the latest technology IGU with two sheets of coated glass and an argon filled 20mm cavity.
The lower the u value the better, since it is a measurement of the amount of heat that passes through a product.
4mm glass single glass pane u value 5.4
28mm clear glass sealed unit 2.7
latest technology 28mm Solarvitreous IGU 1.0
There is also the issue of solar radiation to consider, which will add to the thermal performance of the glass, this is especially important on South facing glass, so the orientation of the installation is an important consideration.