While Gas heating may be rationed, I doubt electricity as a whole will be so:

- Move to more energy efficient dwellings

- Get good insulating windows

- Get an AC/heat pump

- Substitute old appliances with more modern and efficient ones

- Get an induction stove, much more efficient than a gas stove

- Thermal clothing does wonder.

- You can easily sleep in a cold room if your bed is properly insulated, if you are still cold consider heating your bed with an electric heater.

- If you take frequent showers/baths, consider doing some of them with cold water (which has a lot of health/cognitive benefits btw), for baths you can easily install a filtering/reflow device like the one used for small pool, insulate the bathtub, for showers simply use less hot water / less water in general.

- Almost all EU states should have programs in place to ease these sort of upgrades