What's the insulation and air sealing opportunity like in Europe? I wonder how much of a permanent reduction can be done with retrofits for places that haven't had them done yet.
Multiple successive governments have started grants to share the cost of insulation, however these come with onerous paperwork requirements, complex financing schemes, accreditation schemes for contractors, and then are cancelled 18-24 months in due to low takeup. It's gotten to the point where the small companies that provide these services don't even try to join the schemes because they know it won't work out.
However Europe is a large place. Some places are much better than others. Some people live in a "passive house" already and so have no opportunity - or need - to do better, while others live in a house that may as well be a tent for as bad as it leaks. There are places where almost every house is well insulated and so people living there think all of Europe is in great shape, meanwhile the next country can be in terrible shape.
Although it seems F and G flats will be illegal to rent soon in my city, so that could help.
Meanwhile, I've had single pane windows in most of my flats. Can't wait to move somewhere better insulated (I can hear the wind hissing through small gaps in the sliding windows right now). This is in a major city in France.