How much will it cost to have my windows cleaned? By using the estimator guide you can get an idea of how much a regular clean would cost (remember we also clean the frames and sills too). To achieve the best results, you should consider a monthly or two-monthly clean. The longer the time between cleans the more the dirt and the workload increase. If cleaning is less frequent, there may be a slightly higher charge to reflect the additional time and effort it takes to get your windows bright again. Internal window cleaning may be available on special request, but this is more energy and time intensive and would usually at least double your charges.