Double Glazing Explanation
The clock which provides the time which follows (in this preview) is about ten minutes slow (someone delete that when it no longer applies).
Maybe "Double Glazing uses two window panes with gas or a vacuum between, to reduce heat transfer in comparison with Single Glazing." - with 'Double Glazing' linking to that Wikipedia page (which I cannot get right). -- John Stockton (talk) 19:01, 21 May 2020 (UTC)