Window units range from 700 W to 2+ kW. The Model 3 has a pretty powerful one, at least 1 kW. That's peak draw, and it'll turn on and off intermittently[1]. Average draw should work out to 200-300 watts for medium.

[1]: Like a fridge. Refrigeration systems are most efficient at full power. IIRC it's due to the restrictor plate separating the hot and cold radiators- it's designed to work at a certain rate of flow, so you'll get gas and liquid mixing at lower power.