Heat insulation is perhaps the most common reason for getting double-glazing. However, if the frame is not right the insulation provided by double-glazing is lost. The worst conductors of heat and therefore the best insulators are wood and PVC-u. Aluminium is a relatively good conductor of heat and so is not the best material if this is of primary concern.
The protection against sound is another great attribute of double-glazing and their isn’t really a clear winner. The relative sound insulation properties are therefore of lesser concern that those of say heat.
Security is always a concern and here we have a clear winner. Aluminium is extremely strong and is the material of choice where security is of major concern. This explains why aluminium is commonly seen on commercial premises. Wood and PVC-u have their weak spots. PVC-u expands during hot temperatures and the expansion gaps required can become weak points for intruders.
Another area that has a clear leader is appearance. Wooden frames are easily the most attractive frames. The timeless appeal of wood suits both modern and period properties. In particular, for period properties it is almost mandatory to have traditional looking frames and in particular sash windows. … Read the rest