Insulated Glass
Two or more panes separated by a spacer and sealed at the perimeter. The captured cavity — not the glass — does most of the insulating work. When that perimeter seal fatigues, the cavity breathes, moisture enters, and the unit fogs.
Glass Education
The glass is not what insulates.
Nearly every meaningful energy gain in a restored window comes from three things you cannot see: a sealed gas cavity, a microscopic metallic coating, and a low-conductivity spacer at the perimeter.
Interactive cross-section
Hover or tap a layer of the insulated glass unit to see what it does. The glass itself is a poor insulator — the performance lives in the cavity, the coating, and the seal.
Low-E Coatings
A microscopically thin metallic oxide layer that reflects long-wave infrared while passing visible light. It keeps radiant heat inside during winter and outside during summer, typically cutting heat transfer through the glazing by half.
Argon Fill
An inert gas denser than air, slowing convection inside the cavity. Paired with Low-E and a warm-edge spacer, it meaningfully improves center-of-glass performance at no visual cost.
Tempered Glass
Heat-treated for roughly four times the strength of annealed glass, breaking into small blunt pieces. Required near doors, in tubs and stairwells, and below certain sill heights.
Laminated Glass
Two lites bonded to an interlayer. It stays in the opening when broken and adds substantial sound attenuation and UV rejection.
Energy Performance
U-factor measures heat flow, SHGC measures solar gain, and VT measures visible light. The right combination depends on orientation and climate — not on a single 'best' number.