Our existing fan is old, inefficient and extremely loud. I believe it is an old P Series centrifugal extractor made by Greenwood Airvac, although I am unable to be certain as the model and serial numbers have both faded to the point that they are unreadable. A picture of the unit without its cover is included below:

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I have found a model I would like to replace it with - an ST100B Silent Tornado Hi-Power Bathroom Fan, but I don't understand enough to know whether it will be possible to easily replace one with the other. For example, do they require different diameter venting holes?

I intend to employ an electrician to do the actual work, so I do not require any detail beyond whether the model I have chosen is a suitable and easy to install replacement.

2 Answers 2


It's difficult to say without seeing the current installation. Rather than answering the question directly, I'll give you some tools to make the assessment yourself.

There are a few basic considerations when seeking a replacement fan, aside from feature preferences...

  • Housing size
  • Housing mount type and location
  • Grille size (for coverage of the existing ceiling opening)
  • Duct size
  • Duct position

If any of those don't match, you'll need to decide whether the necessary changes are feasible and acceptable. That's mostly a matter of prerogative, so we can't say.


Good news! You can STILL buy the P series extractor fan! I'm in the same situation and looking for a replacement motor, but for around £200 a new unit is available. - which is my plan B if I can't lube the motor bearings.

  • Well, just an update on my previous (in case someone else is looking for a solution to the Greenwood Airvac, the motor is a Torin one, and is indestructible! It is a doddle to unscrew it and remove the rotor and relube it with some superlube. My unit dated 1984 is now running silently again.
    – Nicam49
    Commented Jan 25, 2023 at 16:24

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