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Bathroom Fan Only Works When Light Is On (Easy solution)

If you’re used to having your bathroom fan and light controlled by separate switches, you might have taken that freedom of choice for granted. For those who have lived in spaces with multiple switches or even with the luxury of an automatic fan, it can be confusing and even concerning to move into a new home and find that only one switch controls both appliances.

Whether you were led here by concern or by frustration at not being able to choose to turn on one at a time, you’re in luck. It’s perfectly normal to have only one switch in the bathroom, but if that’s a problem for you, there’s no need to worry. Rewiring your bathroom light and fan to be on two different switches is a relatively simple fix.

Linking a bathroom fan and light is common practice. It ensures good ventilation. However, it also creates unnecessary heat and energy loss as well as inconvenience. It is fairly simple to separate the two onto their own switches, but it may have to be carried out by a licensed electrician to be legal.

Linking Fan and Light Is Common

While it may be annoying or confusing that your fan and light are hooked up to the same switch, it’s extremely unlikely that this was a mistake.

This kind of wiring is actually pretty common practice, especially in bathrooms without windows. That makes sense when you consider that unless you’ve got night vision, not having a window means you’ll probably be flipping the light on when you use the bathroom.

Technician tightens the last screw on the fan time switch

You’ll likely be needing the fan for a decent number of your bathroom trips, too. While showering, bathing, and going to the toilet (odor control/privacy) are the only things you might think to use the fan for, there are only so many things that a bathroom is used for in the first place. Showering, bathing, and using the toilet make up the major percentage of these bathroom tasks, so having the fan and light working together isn’t necessarily unreasonable.

Additionally, linking the light and fan together makes it easy to ensure that your bathroom will always be well ventilated. This can be a saving grace to those who are forgetful or simply uninformed about the consequences of poor ventilation.

Disadvantages of Linking Bathroom Fan and Light

While having the light and fan linked together can be a major benefit in making sure your bathroom is well ventilated, there are several drawbacks to consider as well.

  • While showering is a regular occurrence, the bathroom is used far more frequently for tasks that don’t create any steam that needs to be removed. When you’re just in there to use the toilet, brush your hair, floss your teeth, or wash your face, having the fan on becomes a waste of energy.
  • Running the bathroom fan when it isn’t necessary also causes the air in your house to be vented out. If the temperature inside your home is much warmer or cooler than it is outside, this will result in your HVAC system working to compensate for the loss, running up your energy costs.
  • Depending on your household, the sound of the fan may range from harmless background noise to a bit more of a serious disturbance. Maybe the fan’s whirring keeps waking up whoever sleeps closest to the bathroom at night, leaving you to stumble around in the dark whenever you need to make a nighttime toilet trip.
  • It’s recommended to leave the bathroom fan running for at least 20 minutes after a shower in order to ensure all the steam has been removed. Unfortunately, that means properly ventilating your bathroom wastes energy if your fan and light are connected, as the light must also be kept on.

TOPGREENER Dual Tech Humidity Sensor Switch, Infrared PIR Motion & Air Moisture Detection, Bathroom Fan & Light Control, Adjustable Timing, Neutral Wire Required, UL Listed, TDHOS5, White

Separating the Fan and Light

Although some people are perfectly content to keep their fan and light connected, many others would prefer to split the controls due to the many disadvantages that come with only having a single switch.

While separating your fan and light from each other is both possible and a relatively simple project as far as electrical work is concerned, you must ensure that it is done carefully and legally.

Before you start, check your local codes and regulations to confirm that it is legal for you to do your own electrical work. It’s likely that you will be required to have a licensed electrician perform the job for you in this case, but there are places in which you may be allowed to rewire the fan yourself.

For example, the Massachusetts Electrical Code would permit you to do your own electrical wiring as long as certain conditions are met. Those conditions would be that you yourself own the property, that you live on the property, and that the property is residential, not commercial. You must also have approval from a Wiring Inspector before beginning the project.

If you are legally allowed to do your own electrical work, the following videos may be helpful to you in planning and understanding what you will need to do.

This video will be helpful if your fan and light are separate units that have been linked together at the switch.

If your fan and light are part of a combined unit, this video will help you understand how to rework the wiring to split the control.

Table of Tools and Products for Project

This table is a comprehensive list of tools you may need if you choose to perform this project yourself.

ProductAmazon Link
Fluke 1AC-A1-II VoltAlert Non-Contact Voltage TesterView
Fluke 117 Electricians True RMS MultimeterView
Sperry Instruments GFI6302 GFCI Outlet/Receptacle Tester, Standard 120V AC Outlets, 7 Visual Indication/Wiring Legend, Home & Professional Use, Yellow & BlackView
Ideal Industries – IDI61534 IDEAL INDUSTRIES INC. 61-534 Digital Circuit Breaker Finder with Digital Receiver and GFCI Circuit TesterView
DEWALT 20V Max Cordless Drill Combo Kit, 2-Tool (DCK240C2), Yellow/Black Drill Driver/Impact Combo KitView
WAGO 221 Lever-Nuts 75pc Wire Connector Assortment Pack with CaseView
Grounding Pigtails with Ground Screws (Pack of 50)View
VOLTCLAW-12 Nonconductive Electrical Wire PliersView
Milwaukee 1000-Volt Insulated Screwdriver Set and Case (10-Piece)View
Klein Tools 11055 Wire Cutter and Wire Stripper, Stranded Wire Cutter, Solid Wire Cutter, Cuts Copper WireView
KNIPEX – 13 88 8 US Knipex Tools LP – 13888US Electrical Installation Pliers Red/YellowView
Leviton 5634-W 15 Amp, 120/277 Volt, Decora Single-Pole, AC Combination Switch, Commercial Grade, Grounding, WhiteView


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