Can't say right now, but I'm having 20 of them installed within the next 4 - 6 weeks as soon as they come in. From my comparisons and shopping around they seem like a good window. I forget the series/model (maybe 7000 series) I'm getting, but they're double hung, low-e, argon gas, double pained, and double glazed (I believe). The person installing them gave a great price (referral by friend that has used him 2 times along with other friends and family members of theirs). Anyway, from the brochure they are Energy Star rated and also had a very low U rating (like .29)...a couple of the things I was looking for. Yes, price was a factor, but given the info I know about the window they seem like a quality window. My quote was ~$6700. Sounds cheap to me, and the next cheapest bid was closer to 8k, and all the way up to ~14k (Home Depot....stay away). The guy doing the work has very low overhead so I'm sure that played a major role in the price....I'm not sure I'd expect to find anyone that would come in that reasonable (ie cheap).