We have been using our energy rated windows now for some time with our Prior DIY conservatories. Why do we do this? Simple - we can as we manufacture the windows ourselves. However the main reason for fitting them as standard to our conservatories is that hardly anyone else does.
We feel that there is no point having a nice shiny DIY conservatory that is too cold in winter or too hot to use in the summer. There is no point as it becomes almost unuseable for half the year. However with energy rated windows fitted, it is cooler in the warm weather and much warmer and easier to heat when the cold weather arrives.
What is the difference? A standard PVCu double glazed window has two 4mm panes of glass seperated by a metal spacer bar and are usually in the region of 24mm thick from front to back. A few years ago, these were a vast imrovement on the old metal framed single glazed windows that were fitted to many houses. They were also vastly superior to the old warped wooden sash windows with their miles of foam draught excluder attempting to keep out the wind.
Enter the new generation of windows - the energy rated windows. Our standard one is a 'C' rated window which is probably way better than the existing glazing in your house! These use again 2 4mm panes of glass, but the glass is not standard stuff. It is Planitherm total softcoat glass and the thickness of the glass unit is 28mm instead of 24mm. With a less heat conductive spacer bar and the fact that the glass unit is filled with Argon gas, the transformation is complete. Argon being an inert gas is not heat conductive and the combination of Planitherm total glass and aArgon gas means that hardly any heat is lost through the glass units. Similarly the PVCu frames are designed to work in conjunction with these glass units and are also multi chambered affairs. When tested by the BFRC ( see www.bfrc.org ) we have managed to manufacture a window which meets the 'C' rating, and indeed we also manufactue an 'A' rated window if an upgrade is required.
Low heat loss means lower heating bills and more saving of your hard earned cash, which is surely why you want a DIY conservatory in the first place!