What specifications are important when buying DG???

[Antony2008]

I’m just in the process of inviting double glazing providers round to my 82 year old Mum’s house in South Yorkshire and am preparing a spreadsheet to help Mum compare like for like quotes.
Not being a builder/joiner/window supplier, I’ve no doubt my spreadsheet’s lacking pertinent info’ which I’m hoping that the knowledgeable in this forum can point out.
So far I’m aware of and understand the following sufficiently well :- Low E glass (Pilkington K/Planitherm; argon/xenon filled etc); toughened safety glass; 16/20mm cavity; warm edge spacers; WER; FENSA/CERTASS/VEKA; Warranty & IBG.
I’ve had a look through various posts on the forum and seen brief solitary references to 3 and 5 chambers (I assume this is some kind of frame fabrication), and mention of Kommerling products, but nothing much else. What I can’t seem to find are details that can be compared against one another when considering frame profiles, ventilation, hinges, locks/other security measures etc. Any pointers on what I’ve missed & what products/suppliers to consider & compare would be greatly appreciated (especially by Mum!).
Many thanks in advance.
Antony

 

[foxhole]

http://www.double-glazing-info.com/Choosing-your-windows/Types-of-glass/Low-E-energy-saving-glassn

 

[Antony2008]

Thanks for your reply foxhole.
Further rooting around the internet brought up this site:- http://doubleglazingsecrets.com/html/profiles.html, which has filled in many of the blanks.