You are buying your first apartment or house in the Grand Duchy. Here are those enigmatic alphabet energy ratings explained:
G/H - Solid as a rock. Forget about the ghost in the attic, you don't speak it's language anyway.
F - A few cracks here and there. Outside tap. Radiators give you migraines. Has a poltergeist instead of a ghost, so don't leave any kitchen knives out.
C/D/E - Nobody seems to live in one of these!
B - Air is moved from one room to another, WTF??
A - Mould appears (and does not leave). Garages flood every six months via your cellar.
AAA - Who needs windows?
AAAA - Has a glass ceiling for the arboretum. Costs thousands of euros per month just to keep everything tropical.