Presently, houses today are designed to have two walls (outer and inner) acting as the cavity for preserving heat within your property with wall insulation; as a result, the heat is unable to dissipate.
The same concept applies to double glazing windows with argon gas in between the panes; as a result, once heat passes inside your property it’s unable to pass through due to the vacuum separating the two glass layers.
The more panes in between, the more heat will remain trapped inside while reducing the level of sound pollution from the external environment at the same time.