Cooking Q&A: Preheating The Oven?
How long does it take an oven to preheat?
The average time to preheat an oven to 350° is about 15 minutes, but the time varies depending on the stove. Older stoves may take longer to preheat; some newer stove models have a fast preheat feature.
If you're preheating to 450°, add another five minutes to the time. The only way to figure out how long it takes your oven to preheat is by testing it with an oven thermometer.
Place the thermometer in the center of a rack set in the middle of the oven, then turn the oven to 350°. Set an oven timer, then check the temperature on the thermometer at 10 minutes, then again at 15 minutes.