When specifying conservatory glass it is very important to consider the orientation of the completed room. This will obviously influence how much direct sunlight the room be subjected to and what will be the effect of this on the temperature and brightness within the room.
This article deals with recent additions to the options for North facing conservatory specification.
With over 20 years experience in the construction on bespoke conservatories I have seen many conservatories where incorrectly specified glass has meant that North facing conservatories, shaded from the sun, are too cold to use through the winter. Recently I have had an increasing number of orders from clients who own existing conservatories, that are looking to replace their existing old technology glazing, because the existing conservatory is too cold and too expensive to heat.
As a registered installer of both Pilkington glass products and a member of the Planitherm installer network I have spent a lot of time with the glass manufatcurers, working on the most appropriate use of the latest technology glass coating solutions.
Whilst replacing and upgrading glazing products is possible, it is obviously much more cost-effective if the glass on a shaded, North facing conservatory is specified correctly first time.
Advances in nanocoating technology mean that insulated glass units (IGU) can be coated to retain heat generated within the room as well as rejecting solar heat gain. These coatings take the form of an almost transparent metallic coating applied to the internal face of the glass within the sealed unit and so they are not subject to wear. Careful consideration should be given to the planned usage of the completed conservatory in order that the most energy efficient conservatory glass is specified.
In cases where a North facing conservatory is planned the highest priority should be given to heat retention and rejection of solar heat gain is usually not desirable. In the summer, when the sun is highest in the sky, there may be occasional days when the sun makes the room excessively hot, but these are outweighed by the number of days when some solar heat gain, especially through the side windows is a benefit. Of course with coated glass it is not something that can be turned off, so what works in your favour in the winter may work against you in the summer. Given the uncertainties of the climate, specifying glass is much more of an art than a science.
For a North facing conservatory a good option, especially for the side frames, is the latest Planitherm offering from Saint Gobain. It is a new generation of energy efficient conservatory glass that uses advanced coatings to reflect heat from domestic sources back into the conservatory whilst allowing heat and light from the sun to pass through, warming the room, reducing heating costs and energy bills.
In addition to contributing towards an energy efficient conservatory the glass also reduces draughts and cold spots near the windows, making the whole room usable, and has excellent light transmission properties.
For a North facing conservatory this product is an excellent option, but of course this glass is usually not suitable for a South facing elevation, where rejection of some solar heat makes more sense. For a bespoke, energy efficient conservatory there is no reason why glass with different properties cannot be specified for different elevations of the same building.