Site conditions decide more than the product line
How the unit gets installed, the flashing detail, the sill's condition, frame material, glazing package, trim finish, and which way the wall faces the sun all weigh as heavily as which window you pick.
Build a complete scope
- What is installed now, and whether older sash can be restored instead
- Whether piecemeal past replacements left mismatched units to reconcile
- Each opening measured rather than assumed from an adjacent one
- Solar control and air sealing, which matter more here than U-value alone
- Trim restoration, disposal of removed units, and the warranty offered
Athens context
The local climate points this specification away from the northern default. Humid Georgia summers make solar heat gain through the glass the dominant comfort variable, so the gain coefficient matters more than an insulating value chosen for cold winters. Dense tree canopy keeps shaded elevations damp long after rain, which puts weight on how the opening is flashed and sealed rather than on the unit specification. And a long history of additions means exposure and detailing can differ sharply between one wall of a house and the next, so what worked on the front elevation is not automatically right at the back.