dead-air space

American  

[ded-air] / ˈdɛdˈɛər /

noun

1. an unventilated air space in which the air does not circulate.

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Etymology

Origin of dead-air space

First recorded in 1900–05

Example Sentences

The storm window reduces this to a minor percentage because the dead-air space between the two thicknesses of glass acts as an efficient means of insulation.

From If You're Going to Live in the Country by Lieberman, Frank

This keeps it from being frozen in winter and from being overheated in summer, just as a dead-air space in the walls of a building protects from extremes of heat and cold.

From Northern Nut Growers Association, Report of the Proceedings at the Fourth Annual Meeting Washington D.C. November 18 and 19, 1913 by Northern Nut Growers Association

Or, better still, for the few earliest frames, have double-glass sash, the dead-air space making further protection unnecessary.

From Home Vegetable Gardening — a Complete and Practical Guide to the Planting and Care of All Vegetables, Fruits and Berries Worth Growing for Home Use by Rockwell, F. F. (Frederick Frye)