Ok so with all the experts before I begin I DO NOT work for Serious Materials.
As far as their Quantum2 window goes their overall U-value of the entire unit goes from a .16 on a picture window to a .18 on casements and .19 on double hungs. I will tell you they have a very attractive well performing window and the Manufacturers Service dept. is Top Shelf. As far as Skydawggy's comment it is not a fair or true statement. IMHO
Now before anyone starts yelling I do own a NJ company and one of our lines is Serious Quantum2 so I am just here for facts and answers that are accurate no posts of my website or schilling for my company or anyone else's I will just say that I am a Very Informed Owner and understand the smoke and mirrors that most companies use and I won't have it.
Fire away with any questions and I promise all answers will always be fact!
What are the VT and SHGC numbers on that double hung? Do you know the air numbers off hand too? Just trying to get a feel for that window.
Do you have any cut away images?
Also, I am not sure where Sky said anything unfair or untrue. He was merely challenging the fact that the original poster had been presented with misleading information. Anybody that quotes COG numbers is trying to fool the customer.