The fan is normally outside - so you may hear it outside but shouldn't hear much from inside. The fans do tend to get noiser with age, but that's the same with any appliance.
Are you thinking of getting on ? or do you have one ?
Thanks for your response. We're thinking of getting one - we have an awkward situation where we want to put the fire across a corner (first creating a "false" wall. The former owner of our property ripped out every fireplace and inserted windows where the fireplace had been :( Didn't like the idea of glass with a balanced flue fire - think we might was well get an electric fire as it looks the same!
fan flue/power flues do tend to be noisy. some are worst than others, balanced flue is the way most people go these days. Even if they have a chimney 70% of my customers opt for glass fronted because of the efficiency.