The short answer
Residential exterior-cleaning prices depend on surface, square footage, access, buildup, and treatment required. A small concrete area and a complete house-and-driveway reset should not carry the same price.
What changes the price
Stories, steep grades, difficult water access, oxidation, oil or rust, heavy organic growth, delicate materials, and unusually large concrete areas can change scope and labor.
Pressure versus soft washing
Professional cleaning is not about maximum pressure everywhere. Siding and roofs generally require a lower-pressure treatment, while suitable concrete can receive controlled pressure.
How to compare quotes
Ask what surfaces are included, how landscaping is protected, and whether the quoted price can change without your approval.