Heater type
Fan/PTC ceramic (fast, blowing), oil-filled radiator (slow, silent, steady), halogen/quartz (radiant spot heat).
Why it matters
Type decides comfort: radiant heaters don't warm air, fan heaters dry it, OFRs do neither but take 15–20 minutes to start.
What to check
Buying a halogen for a whole room is the classic winter mistake.