The best extractor fans for bathrooms in Swansea are sized for the room and duct route, rather than chosen solely for the highest advertised airflow.
What makes a bathroom fan suitable in a UK home?
A suitable bathroom extractor fan should remove at least 15 litres per second (l/s), roughly 54 cubic metres per hour (m³/h), for intermittent extract ventilation under Approved Document F guidance.
Work out the room and route first
Measure the duct route as well as the room. Start at 15 l/s, but choose a fan with more pressure where there is no opening window, frequent showers, or a route longer than about 3 metres with two or more bends.
Controls that help after a shower
A timer overrun keeps the fan running after the light goes off; set it initially for 15 to 30 minutes and adjust according to how quickly the room dries.
A fan cannot extract air that cannot enter the room. If the door seals tightly against the floor, the fan creates suction but has little fresh air to replace the moist air. A modest gap under the door or a suitable transfer grille lets the system breathe.
Choose a timer fan for predictable drying; choose a humidistat only when it is correctly set and the duct route is sound.
Size airflow for the bathroom, not just the fan
Start by calculating room volume: length × width × ceiling height. For example, a bathroom measuring 2 m × 2 m × 2.4 m has a volume of 9.6 m³. The 15 litres per second baseline is suitable for many ordinary bathrooms, but it should not be treated as the final answer for every installation. Add capacity where several people shower in succession, there is no opening window, towels dry indoors, or bathroom ventilation must travel through a restrictive route. In those cases, compare the fan’s claimed airflow with its performance under pressure, rather than choosing solely by its free-air m³/h figure.
Best fan models for short wall ducts
For a short, straight route through an external wall, a 100 mm axial fan is usually the sensible choice: it is affordable, easy to service and can meet the 15 l/s target.
| Model | Airflow | Noise | Power / duct | Controls / warranty | Typical UK fan price |
|---|
| Manrose QF100T Quiet Fan | About 21 l/s, 75 m³/h | About 27 dB(A) | About 8 W, 100 mm | Timer, no humidistat, 3 years | £35 to £55 |
| Xpelair DX100T | About 21 l/s, 76 m³/h | About 34 dB(A) | About 15 W, 100 mm | Timer, no humidistat, 3 years | £40 to £65 |
| Vent-Axia Silent Fan 100T | About 21 l/s, 75 m³/h | About 26.5 dB(A) | About 8 W, 100 mm | Timer, no humidistat, 5 years | £55 to £80 |
| EnviroVent SIL100T | About 21 l/s, 75 m³/h | About 26 dB(A) | About 8 W, 100 mm | Timer, no humidistat, 5 years | £70 to £100 |
Budget, mid-range and premium choice
The Manrose QF100T is a practical budget option for a direct wall route, while the Vent-Axia Silent Fan 100T is a strong mid-range choice; EnviroVent may suit buyers prioritising lower noise and a longer warranty.
Check noise in the right way
Noise is measured in dB(A); a quieter fan that runs for 20 minutes is usually more useful than a louder model switched off early.
Choose this if: your duct exits directly through an outside wall, stays close to 100 mm wide, and has no long flexible section or several bends.
Long loft ducts need inline or centrifugal fans
Inline and centrifugal fans are better than basic axial fans when air travels through a ceiling, across a loft, around bends or to a remote external outlet.
A bathroom extractor fan may quote a high airflow in open-air testing but move much less air once it is connected to ducting. Every metre of duct, sharp bend, flexible section, insect mesh, external grille and backdraught shutter adds duct resistance and increases static pressure. A basic axial fan is normally effective on a short, straight 100 mm ducting run through an external wall, while an inline extractor fan or centrifugal unit is usually more reliable for long duct runs, ceiling extractor fan installations and loft routes. Check that the selected unit is designed to maintain useful bathroom airflow at the pressure created by the finished route.
Build the duct to protect airflow
Use smooth rigid ducting where possible, keep bends broad and few, stretch flexible duct tight, and insulate ducting in cold lofts to prevent condensation collecting and dripping back toward the ceiling.
Know the full installed cost
A basic replacement on an existing short route may cost £120 to £220 supplied and fitted. A new inline system with ducting, external grille, insulation and electrical work commonly costs £300 to £650, depending on access and route length.
For long ducts, spend first on the route: adequate duct diameter, fewer bends, insulation and a free external outlet. Fan upgrades work best after those basics are right.
Choose this if: your fan is ceiling-mounted, the outlet is across a loft, the route has several bends, or a normal axial fan leaves steam on mirrors after a shower.
Stop repeat condensation and check bathroom safety
Persistent condensation usually results from inadequate real airflow, a short overrun, no replacement air beneath the door, or defective ducting.
Fix the fault before changing models
Check the external grille, fan spigot and duct for blockages, splits, crushing or narrowing. If the room remains wet after the fan stops, increase the timer to 15 to 30 minutes.
New wiring, circuit changes, work near bathroom electrical zones, or uncertainty over earthing, IP ratings and RCD protection require a qualified electrician; ask whether certification or notification is needed under Part P in Wales.
An extractor fan will not solve damp caused by a plumbing leak, rain penetration, poor insulation, an unvented tumble dryer or structural mould. Do not attempt new bathroom wiring or work in electrical zones yourself, and tenants should obtain the landlord's permission before altering the fan or duct route.
Choose this if: condensation continues after a replacement, the fan is near a bath or shower, or the work needs new cable, a new outlet or loft ducting.
Bathroom fan installation and safety checklist
Before installation, confirm that the fan discharges outdoors rather than into a loft or wall void, that the external grille is clear, and that insulated ducting is used where warm moist air crosses a cold loft. Check that the room has replacement air through an undercut door or transfer grille, and that the fan’s IP rating and position are appropriate for the relevant bathroom electrical zones. The circuit should have suitable RCD protection and a safe means of isolation for maintenance. In Wales, new wiring, alterations to circuits and work where electrical-zone requirements are unclear should be assessed and completed by a qualified electrician in line with Part P requirements and the manufacturer’s instructions.
Common questions
The best choice depends on the duct route: a quiet 100 mm axial fan suits short wall ducts, while long or bent routes usually need inline or centrifugal extraction.
Aim for at least 15 l/s, or about 54 m³/h, and choose greater available pressure for long, bent or restricted duct runs.
Is a humidistat better than a timer fan?
A timer is usually more predictable, while a humidistat helps where people forget to use the fan but cannot overcome a blocked duct or airtight door.
Why is my bathroom still damp with a new fan?
The duct may be crushed, uninsulated, too narrow, disconnected or venting into the loft; also check the external grille and door air gap.
Only simple non-electrical cleaning should be considered; new cable, bathroom-zone work and uncertainty over electrical protection require a qualified electrician.
Choose the route before choosing the fan
For most Swansea bathrooms, a quiet timer fan on a short, direct external-wall duct offers the best value. For a long loft route, choose an inline or centrifugal system with smooth, insulated ducting and a proper external outlet.
