Most of my problem would be finer dusts, most of my chips and shavings end up in a large container under the lathe, my extractor unit is outside the room but when switched on the noise is loud !!
I am considering buying a 12" portable fan ,like the ones we use in building work to expel dust from the room when you are demolishing a wall etc ,these I have used a lot and they sure expel the crap!
I would mount this in the roof space and duct it in 12" to the back of my workshop and outside, then bring the flexible 12" inlet into my craft room ceiling above the lathe and have it on a rise n fall cable to lower it to height above the lathe chuck.
These are relatively quiet units, and are about £100 ,light and portable and less energy consuming, I will borrow the one I've used for building work and give it a try in the next week! Thanks for all your reply's