If ypu've got a standard roof, its not a MASSIVE job to get up there and install some additional insulation bats yourself. Best tip for the splity though, get the WIFI module so you can control it with your phone. Then set up schedules so it comes on before you get up in the morning.

@RustyRaven @just_kitten I'm fortunate to have a house that was built for alpine conditions, so the insulation is exceptional. I want double glazing too, currently making do with less than ideal plastic cover on Velcro over the windows (like properly sewn ones designed for this use) which does help a lot, even though they look a bit naff.