The Emerge Series is the most energy efficient family of aluminum products Quaker offers, merging structural integrity with thermal qualities. The Emerge product line was designed to get U-Values & SHGC values to depths rarely seen in aluminum windows. The E300 Series has a good mixture of all traits. A modern look including an integral lip on the meeting rail, blended with excellent thermal values and AAMA ratings in the mid-to-upper CWs. If softer aesthetics are part of the equation, then opt for the E303 Series. The most heavy-duty of the Emerge picture windows are those found in the E500 Series. The E600 Series has every angle covered. Superior structural performance and industry leading thermally capabilities.