Double glazing is a better thermal insulator than secondary glazing; however secondary glazing is best at maintaining out noise pollution. Perspex or plastic is more cost-effective and may do an analogous job, but will discolour with age; it is a lot more commonly used in companies or Business office properties. https://streetart22221.bligblogging.com/26835952/an-unbiased-view-of-bloomsbury-secondary-glazing-solutions