please help me with extractor fans (exciting!)

[WillieWaggledagger]

this is extremely boring but i have absolutely zero experience or knowledge of this sort of thing... i've tried to put down what i think is relevant, but apologies for tedious level of detail

we've just bought a house where the bathroom doesn't have an extractor fan, and it's a priority for us getting one put in - having lived in a rented house without an extractor fan we know how much of a pain it is, and we are aware of some damp problems in that part of the house and i'm sure the lack of extractor fan is a factor

the bathroom is on the ground floor at the end of a single-storey extension, so it has two external walls (the third is attached to next door's kitchen) and a pitched roof. there is currently no access to the roof space. the highest point of the pitch is about 1.5m above the height of the ceiling. it's not a large bathroom, only about 2m x 2m

it needs to be a ceiling fan as the bathroom is tiled up to the ceiling and we would rather not mess it up. as there is roof space this also seems like a sensible option, and we can get a loft hatch put in at the same time as access would be handy (and we can check and possibly add to the level of insulation in the roof at the same time). the hatch would likely be put in in the utility room outside the bathroom

the bath (with shower head) is positioned along the wall adjoining next door's kitchen, which is also the area below the highest point of the roof. i'm not sure how much space there is, but presumably the fan and associated electrics would need to be positioned on the ceiling away from the bath and shower, but this would be close to the lowest point of the roof

does anyone have any advice or recommendations for ceiling extractor fans? important things to think about etc? i don't really know where to start...

someone mentioned heat recovery extractor fans as another option, but i think these are considerably more expensive and i don't know whether it's worth it. having said that the bathroom isn't that warm (it has a heated towel rail for heating but inevitably this becomes well-insulated by towels - previous owner's choice, but we aren't likely to be able to prioritise putting in a separate radiator or larger towel rail, nor is there really the wall space).

any advice would be very welcome!

[PigletJohn]

if you have a loft-mounted fan, the electrical fan and connections will be in the loft, not in the bathroom. So you can put the extract grille over the shower (and one close to the WC)

You will have duct from the grille to the fan, and the fan to the outside world. Rigid duct or soil pipe is better than flexible convoluted hose, because it does not sag and accumulate fluff and condensation. Wrapping the duct in loft insulation will reduce condensation, but slope it towards the outside vent so any water will drip out.

Have the fan wired to the light fitting so that it comes on with the light switch and runs on for 20 minutes. A humidstat is not so good. It will be very quiet. Have the hatch at the highest part of the roof, but where you can stand on steps and reach the light fitting and the fan.

Look at the extract rate (quoted in cubic metres per hour) and the noise (quoted in db) of some of these ducted fans, and compare them to the small wall-mounted ones. for example

[WillieWaggledagger]

thanks so much - that's good to know about the electrics and the duct

we might need to have the hatch in the bathroom in that case, i will have a measure

thanks again