Warms in advance

• Gets ready, as an oven
• Prepares an oven, as for baking
• Starts the oven early
• Gives advance warming
• Warms up ahead of time
• Prepares for cooking, as an oven
• Prepares an oven before baking
• Readies the oven

Wiktionary Word definitions in Wiktionary
vb. (en-third-person singular of: preheat )