Understand It Requires Special Skills
Window cleaning might look quite easy but actually when one gets into the job, it is not as easy as it seems. It requires quite a bit of skill, training and experience. Different windows have different problems and therefore one cannot paint all of them in the same brush.
Look For Experience
It would be better to always look for professionals who have the right experience with them. Since there is no qualifications or certifications required for this job, as customers you must look for those window cleaners who carry with them at least eight to ten years of experience. Experience also brings along with expertise which also should be one of the factors when hiring these professionals.
An experienced and professional residential window cleaning company will have plenty of experience cleaning the most elaborate custom homes. Call and ask how many custom homes they service on a regular basis. If they do not do custom home window cleaning, then chances are they are not the professional company you may be searching for.
Do They Have Special Tools & Equipment?
Since grime and dirt on windows can be extremely tough to remove, you must look for those cleaners who carry with them the right tools. They should have special cleaning agents, and special devices to cut open stubborn dirt and grime. Further they should be able to do a thorough job but at the same time must ensure that they take adequate care of the window. Glass windows in particular are very fragile and therefore they need to be handled with care.
Finally, if you are hiring window cleaners be sure that they and their staff are adequately covered under insurance. This is all the more true when they could be working at difficult and potentially dangerous heights.