Hair Dryers: 1200-2000W
Electric blankets: 120W
Bar Heater: 400 – 1200W
Using any of the above appliances puts a heavy draw on your caravans electrical system. You can run these appliances through an inverter while on battery power, to give you 240V mains power, however, you need to limit their use to mere minutes a day.
Consider a diesel or gas space heater instead of a bar heater. You can also get 12V hair dryers which can do a decent job.