i have been sending emails out for some time and have got loads of work from it.
this is what i say
Dear Sir/Madam,
(your business name)
I have recently invested in a new technology that enables me to perform external window cleaning up to 4 floors high, all from the safety of the ground. I can now clean all your windows, fascia, roof signs, glass roofs, conservatorys and shop signs. This system works by using lightweight carbon fibre poles and highly purified and deionised water that when dry leaves your windows clean and smear free. Because I stay on the ground, many of the normal health and safety concerns are a thing of the past, and it also means reduced disturbance.
Because this system does away with ladders and expensive access platforms (And the risks involved with their use) I am confident that I can offer savings, and improved results when compared to your current cleaners, and would enjoy the opportunity to provide you with a quote.
( your business name) is a local company and is fully insured.
If you would like me to quote, for any of your window/sign cleaning requirements, or have any questions, please do not hesitate to contact me on (your number) or via e-mail (your email)
Best Regards