I am in the process of getting quotes for vinyl replacement windows for my new home and you can throw me in the 'confused as heck about Low E squared' crowd.

I received the first quote yesterday from a local SoCal installer that came recommended from our home inspector. This guy apparently sells his own brand of windows (American Integrity) and from what I can tell, is legit. But he is reluctant to send me technical information regarding what he is calling Low E2 spec'd windows. Instead, he directed me to Guardian's website and is telling me that the glass is the ClimaGuard 55/27 Low E. Of course there's no information that I can see on the Guardian site that reference U-Factor, SHGC, VT, etc.

When I spoke with him today, he mentioned that the LowE and LowE2 is the same thing, but that the LowE2 has a lower heat gain coefficient. Is he trying to dumb it down for me, or should I have reason to be concerned at his lack of providing tech specs? I have a bit of an uncertain feeling, as he is also quoting me for a higher STC rated window (at my request), but can't show me why its a better sound rated window.

In my research here I've read a lot of good things about Simonton, so I have some quotes lined up for installers who carry those windows as well. But I also wouldn't mind supporting a local business if his product is good.

BTW, his quotes came in at $410 for the 44"x43" sliding windows and $1,534 for the 69 1/4"x79" sliding doors for these supposed Low E2, SoundGuard (STC 32) products, tax and install included.

-Mike

Climaguard 55/27 is Guardian's low SHGC offering. The numbers relate to the VT and SHGC - 55% visible transmittance and 27% Solar Heat Gain Coefficient.

It is a softcoat LowE2 product - which generically means that it has two layers of silver - with performance standards something of a mix between triple silver and double silver products.

For example, comparing to Cardinal's LoE2-240 low solar heat gain coating and also to Cardinal's LoE2-270 and Viracon's E1-55 which are dual silver moderate solar heat gain products:

Climaguard 55/27 - VT = 55, SHGC = 27, U (cog) = .29
Cardinal 240 - VT = 40, SHGC = 25, U (cog) = .30
Cardinal 270 - VT = 70, SHGC = 37, U (cog) = .30
Viracon E1-55 - VT = 49, SHGC = 36, U (cog) = .31

Technically, LowE and LowE2 are not the same thing, but the term LowE is often used generically to refer to any low emissivity product. A bit more precise would be to consider LowE as either a pyrolytic (hard) coat or single silver soft coat product - or typically high solar heat gain coatings - whereas LowE2 (versus LoE2, or correctly LoE squared, which is specific to Cardinal's coating terminology) refers to dual silver soft coats which can be either low or moderate solar heat gain (as noted earlier), and LowE3 refers to triple silver layer low solar gain coatings.

I would suspect his reluctance to discuss technical details may be more his lack of product knowledge than any attempt to "hide" anything from you - IMO.