Windows, Doors, and Exterior Openings

Air leakage rating measures how much air can pass through a window or door assembly.

Argon fill is a gas placed between window panes to reduce heat transfer.

Condensation is water that forms when warm humid air hits a cold window surface.

Door handing describes whether a door is left-hand or right-hand based on which side the hinges are on when you pull the door open.

A door sweep is the seal at the bottom of a door that blocks air, bugs, and water.

DP rating is a measure of how well a window handles wind pressure and water resistance.

An egress window is a window large enough to escape through in an emergency.

Glazing is the glass part of a window or door. It includes how many panes and what coatings and gas fills are used.

Laminated glass has a plastic layer between panes that holds the glass together when it cracks.

The NFRC label is the window performance label that lists ratings like U-factor and SHGC.

SHGC measures how much sun heat passes through glass. Lower blocks more sun heat.

Shimming is using thin pieces of material to make a window or door sit straight, level, and supported.

Tempered glass is heat-treated safety glass that breaks into small pieces instead of sharp shards.

U-factor measures how easily heat moves through a window or door. Lower is better.

A warm-edge spacer is the strip around the edge between window panes. It is designed to reduce heat loss at the glass edge.

Weatherstripping is the seal around a door or operable window that blocks air and water.