Acoustics - The properties of a room or building that determine sound transmission and its effects.

Ambient Noise – The surrounding noise in an environment.

Buffer Zone – The dead air cavity between interior and exterior windows, which enhances acoustical and thermal insulation.

Dual Pane Window (or Double Pane Window) – Two sheets of ordinary window glass configured to be slightly separated by air or gas. Their ability to control sound penetration or heat transfer is better than single pane windows (see below), but still limited.

Exterior Window – Any window that is in an outside wall of a house or building.

Interior Window Treatment – A unique window product installed in front of exterior windows on the inside of a room. These windows are designed to virtually eliminate noise, air, UV ray, and allergen infiltration, as well as drastically reduce costly heat transfer with the outside environment.

Interlayer - Polyvinyl Butyral (PVB), a transparent layer, normally .030” thick, used in the middle of laminated glass (see below) that provides noise and thermal attenuation and renders glass shatterproof, like a car windshield.

Laminated Glass - Two layers of glass joined together by means of an interlayer (see above). Laminated glass is safer and more secure than ordinary glass.

Lift-Out Panels – See “Stationary Panels,” below.

Low-Emissivity (or Low-E) - Impregnated laminated glass that reflects heat back to the same side of the glass from which it originated. The heat originating from the indoors is reflected back inside, keeping heat inside in the winter. The heat originating from the outdoors is reflected back outside, keeping the inside temperature cooler in the summer.

Replacement Window – A window – usually plastic or vinyl – that is installed to replace a removed window.

Shading Coefficient – The amount of solar energy that enters through a window.

Single Pane Window – One sheet of ordinary window glass that is the only separation between the outdoors and the indoors on an exterior wall.

Sound Transmission Coefficient (STC) – STC is defined as the ratio of vibration energy (sound) transmitted through a material to the sound energy incident on the material. It is an exponential value that portrays how much noise is stopped by something.

Sound Transmission Loss (STL) - The ability of a material to alter sound waves, thereby minimizing the passage of sound expressed in decibels (db).

Soundproof Windows – Interior window systems that minimize the perception of outside noise in the interior of a room or building. Sound Proof Window Treatments cut exterior noise by up to 95%.

Stationary Panels – Non-operable, framed glass panels that can be removed and replaced.

Thermal Control – The regulation of air currents – both warm and cool – and the correlating reduction in heat gain and heat loss.

Ultra-Violet Rays (or UV Rays) – Invisible beams emitted by sunlight that cause skin cancer, oxidation, and color fading.

U-Value – A measure of air-to-air heat transmission through windows due to the difference in indoor and outdoor temperatures. The lower the U-Value, the better.