Whilst it is very difficult to generalise about costs which will vary for all materials in terms of product quality and market conditions, the Northern Consortium of Housing Authorities in the UK has carried out a regular survey of costs of window systems. The Consortium has accumulated a considerable amount of data for the in-use cost of window frames made from different materials. Their data shows that over a 30-year period, the total capital and maintenance costs for a softwood window will be 33% more than for a window in PVC-U, assuming a 10% bank interest rate in a scheme involving 30 windows (40).

An industry study compiled in Germany by AgPU (PVC industry organisation in Germany) has shown that the total investment and maintenance costs for hardwood systems over a 25-year period were 23% more than PVC-U, and aluminium systems were 57% more expensive (41). It is difficult to transfer the results of cost comparisons in one region to the situation in another. However, the marked success that PVC-U windows have enjoyed in the UK market clearly demonstrates their cost-effectiveness in relation to competing materials.

40. UPVC Windows in the 1990s, NCHA, 1991.

41. Positionspapier Fensterwerkstoffe bei VEBA Wohnen, AGPU, Bonn, 1994.