The invention provides low-emissivity stacks being characterized by a low solar heat gain coefficient (SHGC), enhanced aesthetics, mechanical and chemical durability, and a tolerance for tempering or heat strengthening. The invention moreover provides low-emissivity coatings comprising, in order outward from the substrate a first dielectric layer; a first nucleation layer; a first Ag layer; a first barrier layer; a second dielectric layer; a second nucleation layer; a second Ag layer; a second barrier layer; a third dielectric layer; and optionally, a topcoat layer, and methods for depositing such coatings on substrates.