When the flat roof of our large house built in 1998 started leaking almost twee years ago, we realized that the moment had come to do what we knew had to be done: improving the existing roof insulation to modern levels (R=6.0). In order to get a subsidy for this, we also had to improve the crawl space insulation from R=2.5, the mandatory requirement when the house was built. We upgraded to R=7.5. The total cost of all this, net of subsidy, was some 20k euro, of which perhaps half or a bit more was for the insulation part of the project. I can roughly calculate that we saved some third on natural gas for heating. At current prices that represents about 1200 euros a year. In short, the investment was worth it, and all the more since it was funded by a cheap and easy (2%) government subsidized loan. It also increased comfort.
The next stage of our project is to get a full electric heat pump, but supplies are limited and we may have to wait for another year. We are lucky that by now the already quite well insulated house is even better insulated. Our current double glazing is pretty good high efficiency double glazing, but not quite up to the highest modern standards, so we will upgrade that when the current glass needs replacement. Doing such things when something has to be done anyway (as with our roof) is the most economical way to proceed, of course. We also already had floor heating, which makes low temperature heating systems such as heat pumps more feasible.
So by and large I am far from pessimistic. Much of the technology exists and is pretty economical to implement. Of course, the transition needs mandatory standards such as in building, legislation, and investment in infrastructure, but all that is quite feasible. The economist in me is pleased to see that the market mechanism of high energy prices and rapidly declining costs of wind and solar power are good incentives. Of course, this is not to deny the challenges on our way, one of which is to ensure that those on low incomes are not left behind.