If you are taking all your cleaning equipment then you should seriously consider 'quoting' for the work rather than a price-per-hour. You only USUALLY (not always) pay an hourly rate if you are paying for labour only.
The trouble with charging for the time is that a you can end up spending 3 hours in a place doing a job that only takes 2 - yet you have to pad it out and remain on site for the whole time.
Likewise you can be accused of working too slowly or spending too much time going to the loo/having breaks/talking etc and not getting the job done. A lot of folk prefer a set-price for an agreed amount of work, because they know what will be done for what price and you as the cleaner know what to expect.
A good percentage of your customer will have had cleaners already and will be more clued up than us who run the actual businesses! So don't underestimate or second guess, its not worth it.