In reply to zimpara:
Now I may be falling for marketing here but the three layers of insulation above may make it box above its weight a little so it might be pretty warm for a 1.5 kg bag.
That said, I wouldn't trust a sub-2kg synthetic bag for winter and I'd be wary of much less than 1.5kg in down.
To contextualise, my ME Snowline is 1.3ish kg and is winter weight whereas my old Ajungilak Kompact bag was near 2 kg and was chilly in winter.