You may be a homeowner whose house has hard-to-reach windows or a building manager whose building property has a glass façade in need of washing. In either case, you may require the services of a professional window cleaner for window cleaning. In many countries, there would be an industry association setting the industry SOPs and guidelines as well as the certification of window cleaning professionals. These SOPs are essential for the proper execution of cleaning services as well as ensuring the safety of window cleaners in the delivery of their service. The latter is critical as it is often the case that professional cleaners are hired for cleaning windows located in hard-to-access or elevated areas which could be physically risky to access.  

You can get price quotes on a phone call by professional window cleaners:

A professional window cleaner can normally accept phone inquiries. They would be asking you about the numbers and sizes of windows that you want to get cleaned by them, the kinds and condition of the windows, and their location or accessibility. If the windows are standard in size, made of standard materials familiar to the cleaner, requiring no special cleaning, and located in very easy-to-access areas, the professional cleaner may be able to provide a firm quote over the phone. For more complex jobs, professional cleaners would prefer giving price estimates only over the phone and providing a firm quotation on the actual delivery of the service or when the cleaner has done an ocular inspection of the windows. The cleaner needs to confirm if any special house cleaning solutions are required or special equipment will be needed to access windows.

The cost that professional window cleaners will charge as per the numbers of the windows:

Professional window cleaners rarely charge their service based on the number of windows to be cleaned. Typically, they set a minimum basic service fee and add charges based on size of windows, the difficulty of cleaning and accessibility. They will also charge extra for cleaning window accessories like screens, storm windows, etc. On the day of service delivery, the homeowner should make sure to clear windows of objects that could obstruct access to window cleaners. Some window cleaners would be fine with doing window cleaning but some would not be. At the same time, this activity eats up into the time of the cleaner, time better spent on the actual cleaning of the windows. In certain cases, this may require the homeowner to cut branches from obstructing trees or plants, move heavy furniture, remove curtains or blinds from windows, etc. So that you will not have to wait for long and the professional window cleaners will easily complete their job in time.