The timber windows model is based on the specifications defined by the Wood Window Alliance. i.e constructed from high quality, preservative treated softwood to BS EN 942,BS EN 599 and BS 817; constructed from a defect free enhanced substrate and with end-grain and construction joint sealing. The analysis here is limited to frame materials only, however, all window units are factory glazed and assumed to be installed in a recess.
|General Process Description||Timber window constructed from defect-free enhanced substrate and with end-grain and construction-joint sealing; preservative treated; manufactured to BS644:2012 : Fully finished factory-assembled windows and doorsets of various types. Specification|
|Standard window (1230 x 1480 mm, with one side-opening light) in each of four frame materials.|
The LCA analysis - has been carried out using SimaPro 7.3.2 software and the Ecoinvent 2.2 database which accompanies the software. ISO 14040: Environmental Management – Life Cycle Assessment – Principals and Framework has been used as the guiding framework for the analysis contained within this report.The data compares the service life, ownership cost and environmental impact of windows using timber, modified timber, aluminium-clad timber and PVC-U frames.
Service Life Planning - is based on ISO 15686 methodology
Whole Life Cost - is derived using a standard discounting technique, Net Present Value (NPV), which allows two or more alternatives with differing financial outlay/income in different accounting periods to be compared on an equal basis.