I have a positive air extractor in my hall which goes into the loft space - bungalow. Before it was fitted, the company tested the humidity in the loft as it had to be at a certain level for the system to work. It’s a white square grill, fairly flat against the ceiling, about 30 cm square. No one notices it unless I point it out. I was aware of a faint whirring noise at first but now I never hear it. I did pay extra to have a remote to change the speed but I never use it, it just on medium all year round, I don’t think I can switch it off!
Before it was fitted, I spent ages every morning from Autumn to summer wiping down every window. I don’t dry clothes in the house, if they can’t go outside, I use a condenser tumble dryer in the kitchen with a window open. There is an extractor fan in the bathroom which is on when I shower, I squeegee down the cubicle every use and I also leave the window open for an hour or so afterwards. I live alone so not really creating enough condensation for the state of my windows but my bungalow is built on a flood plain close to the water table and has a void underneath it to take any flood water. So a damp place basically.
After the unit was fitted, no more condensation, none! Until I had plantation shutters fitted in my bedroom and found that sometimes, not every day, there was a small amount of condensation just in my bedroom. I now leave the blinds very slightly ajar at night to allow air circulation which solves the problem.
At the time it seemed an expensive solution but as I also found black mould in two of my fitted wardrobes on outsides walls ( no longer there), I thought it was worth the investment to protect the building. My next door neighbours on both sides also have them.