Duvet blankets are sometimes rated in Togs:
- Light weight summer duvet - 4.5 togs
- Spring/Autumn duvet - 9.0 to 10.5 togs
- Winter duvet - 12 to 13.5 togs
However, duvet blankets don't fit as well as most sleeping bags or duvet jackets and require more insulation to be as effective. Click here for some comparisons of insulated jackets.