Pella Proline vs. Lowe's Pella 450
I was in the Pella store looking at double hung windows (for new construction) and picked up a brochure showing that Low E and Argon is "optional" for their Proline series. Then I went to Lowes and their brochure said that Low E and Argon is "standard" for their Pella 450 series. They had some of these Pella 450 windows sitting out and the box for their 450 series said "Pella Proline". I'm confused. Is Lowes 450 series the Proline with Low E and Argon "standard"? It even looks like Lowes is cheaper although it wasn't priced with screens. Thanks for any insight anyone can provide.