You would have thought that changing or fitting a new domestic bathroom extractor fan would be simple. I am afraid it is not quite so simple if you want a satisfied customer and safe outcome. Besides ensuring you select a quiet, economical, vent size, vent length and suitable extract rate there is another challenge. This being the electrical current rating for design of the extractor fan itself. This extra specification check is usually closely related to the price decision.
Some customers notice that an extractor fan can be bought for as little as £20, so trying to explain that (usually) a lot more needs to be spent can be a tricky task. Besides the extra cost for a timer, the quality of construction needed to keep the noise down and probably limited longevity of a cheap one, we now find that some of these cheap fans need to be installed with a 3A fuse in the supply circuit where a 3 amp fuse may not already be installed. If you are paying an electrician to install it then this starts to become costly because often these fans are fed direct off the home 6A lighting circuit. This means changes to the circuit should be done at the same time. Often it will be better value to install a slightly more expensive 6A rated fan which does not need the extra wiring changes to fuse the supply down to 3A.
Bear in mind that house fires have been know to have started from incorrectly installed or poorly maintained extractor fans. They can overheat if the fan blades become overloaded or jammed.
Please be sympathetic to your electrician when he recommends a £50 or more fan instead of a £20 3 amp model.
Also, a message to the manufacturers. If a model of fan needs a 3A fuse or whatever it needs, please can the manufacturers state this clearly on the outside of the box and/or readily viewable in brochure data. This will avoid the hassle of electricians having to open the box and read the fine print on the instructions to find out if it will be suitable for the job