Originally Posted by SEAN

You should receive a 10 yr guarantee on the profile 5 years plus on the DG units you will only receive 1 year on the hardware.
Make sure the units have both K Glass/low E Glass and that they are gas filled-normally Argon.
Also make sure the company are members of the GGF or similar and have the relevant EN/BS certifications.
Also go for a 70mm wide profile 65mm face depth preferably a German extruded system Alusplast/Rehau etc
Make sure they are internally glazed.
Get them to fit split spindle door locks anti snap cylinders and shootbolt espags on the windows Ask are the windows manufactured to Secure by Design approval/Police Authority approval or do they have the certificate
Also ask to see the energy rating certificate for the windows and make sure it has a U Value of at least 1.8
If they are fitting them get them to point the outside,use expanding foam and re-plaster the inside and not use pvc trims also get them to fit internal cills on the price

Hope this helps

Cheers Sean..........