FORD 2007 Explorer v.2 - Manual (Page 78)

the engine is cold and running at higher rpms associated with cold starts.
This rpm increase is required to provide adequate power from the
alternator to the heated windshield and maintain power to the other
electrical functions in the vehicle.
2007 Explorer (exp)
Owners Guide (post-2002-fmt)
USA (fus)
Climate Controls
78