How long does a wood fired hot tub take to heat up?

Most Royal Tubs models reach 38–40°C in 1.5 to 2.5 hours from cold. The time depends on the heater, the tub’s size, the time of year (winter adds about 30 minutes), the starting water temperature, the weather and your firewood. Keeping the lid on and the tub out of the wind can cut heating time by 20–30%.