Every home experiences the unpleasantness of lingering cooking smells and poor ventilation.
With draught-proofing, double glazing and central heating, the result, in the long term, is likely to be the constant presence of condensation which can eventuality damage both the decor and the structure of the home.
And in the kitchen persistent condensation is not only unsightly but also unhygienic.
There are a number of measures that can temporarily relieve the problem, but in the long run the only way to deal with it is to get rid of the stale air completely and replace it with fresh.
To do this you need to install an extractor fan.
Installing a Wall Fan As only the very high capacity extractor fans rate over 100W, your fan can take its power from the lighting circuit.
However, you should check that, including the wattage of the fan, the light circuit does not exceed the safety level of 1200 watts (counting each light as rated at 100 watts).
Before breaking into the lighting circuit for power a hole must be made in the wall to accommodate the fan.
If you have to go through a cavity wall, it must be sealed with a special sleeve that can be obtained from the manufacturer.
This will prevent unpleasant air leaking into the room from the cavity.
The fan is connected to the circuit wiring by 1.
0 mm 2 two-core and earth PVC - sheathed house wiring cable; the connecting point should be a fused clock connection unit.
This makes isolating the fan for repairs easy: all you do is remove the fuse section.
There are three options for obtaining power for the new fan.
You can connect into the circuit at an existing loop-in ceiling rose.
run the cable to an existing junction box (always present if you have strip lighting in your kitchen), or install a new junction box in the lighting circuit feed cable and run the new cable to that.
At the fan end of the new cable connect it to the fixed section of the fused clock connector unit.
With the main switch turned off connect the new cable to the appropriate terminals of the ceiling rose or junction box.
Then connect one end of a length of 1.
0mm2 three-core circular sheathed flex to the fan and the other end to the plug part of the connection unit.
If your fan is double insulated, as in most cases, you need use only two-core flex.
A wall fan is fixed to the wall in almost exactly the same way as a window fan is fitted to a window, the assembly being straightforward and simply a matter of following the manufacturer's instructions.
In some cases ladder strips are used to secure the inner and outer clamp plates, and these may need cutting to length to match the wall depth.
Otherwise the two plates are mounted independently of each other on either the wall or a panel that must be at least 35mm (1 1/2ft) thick.
The rubber gaskets on both inner and outer clamp plates are retained in both cases.
All fans have shutters which close automatically when the fan is switched off and so prevent any draughts.
If your fan doesn't have an integral switch then a separate switch will have to be fitted.
A mounting box should be fixed to the wall at a convenient height below the clock connector.
From the connection unit run a length of the 1.
0mm sq two-core and earth PVC flat-sheathed cable to the switch.
Remember that as one of the wires is the live feed this must be joined at the connection unit end to the circuit live conductor with a plastic cable connector.
The connector should be placed in the box behind the clock connector.
If you want to fit a speed controller in conjunction with a fan that has an integral cord-switch there is no essential difference in the wiring.
It should be located at the same height as the new switch.