I achieved a 50% heating cost reduction after investing in the insulation of an older house. This included replacing the single pane glass. Such properties are

I achieved a 50% heating cost reduction after investing in the insulation of an older house. This included replacing the single pane glass. Such properties are common over Europe; especially in properties built before the 1980s (which thank to the rebuild after WW2 are a decent percentage of all building stock). Overall you'll maybe cut gas usage by 20% in 2-3 of years by insulating those buildings, building out renewable electricity with storage and incentivising heat pumps (which reduce/remove gas usage of resident-owned properties where they are viable).