luftespalter

Luftspalter is a term used in building and architectural engineering to describe an intentional air gap that separates two components in a system. The gap may be sealed or ventilated and serves to influence thermal insulation, moisture management, and acoustic performance. In English, the concept is commonly referred to as an air gap or air spacer.

In building envelopes, Luftspalter appear as ventilation cavities between layers of a wall, between cladding and an inner wall, or behind a façade. They are a key feature of ventilated façades, helping to reduce heat gain on exterior surfaces and to enable moisture drainage and pressure equalization. In glazing, an air layer between panes (as in double- or triple-glazed units) acts as an insulating buffer, while air gaps around window frames can reduce thermal bridging and aid drainage.

Design and performance considerations: The effectiveness of a Luftspalter depends on gap width, the presence or absence of airflow, and the ability to manage condensation. Ventilated cavities may require drainage paths and vents to allow air movement, whereas sealed gaps rely on trapped air as an insulating medium. Poorly designed air gaps can lead to condensation, mold growth, drafts, or compromised structural behavior.

Etymology and usage: The term derives from German Luft (air) and Spalter/Spalt (gap). In English-language contexts, the equivalent terms are air gap or air spacer. The concept is widely discussed in discussions of façade engineering, window design, and thermal insulation.