On average, about 1 hour.
On really cold days, about 1.5 hours…
You can never rush to heat-up a wood-fired oven that is made of castable refractory or firebrick. Doing so can cause THERMAL SHOCK.
Think of it like pouring hot water on a cold windshield. Adding a hot fire to a cold wood-fired oven is an exact equivalent - CRACK!
No matter the brand - if it’s a castable refractory or firebrick oven, you have to heat a wood-fired oven SLOWLY! You need a minimum of 1 hour to heat the oven to cooking temperature. Any faster than that, you could damage the oven.