Installing a bathroom exhaust fan without attic access

How to install a bathroom fan without attic access in 12 easy steps

Replacing an exhaust vent fan won’t take long if you follow our 12-steps guide. Here are some life-saving tips on how to install a bathroom fan without attic access. All you’ll need is a stepladder and the simplest tools to DIY. Also, read to the end to find out what other ways you can vent your bathroom if there’s no vent to the outside.

What to think about before buying a new bathroom fan

Perhaps one of the most important criteria is the correct fan size. To choose exactly the diameter of the grate correct orientation, make measurements of the exhaust hole then you can find out what size you need.

An alternative may be the following method breaker box. Just look at the same size of your old bathroom exhaust fan unit. It is usually indicated on the circuit breaker box in which the exhaust fan turn was sold.

If you bought a larger exhaust fan, do not worry, its edges are easy to file.

Installing a bathroom exhaust fan from inside the room

Low profile & retrofit exhaust fans

If you have little space in the ceiling drywall hole, you may consider purchasing old bathroom fan a low-profile new bathroom exhaust fan – these exhaust fan has a smaller body (especially thickness) than conventional bathroom exhaust fan and will facilitate installation without access to the attic.

The device is a small object that, due to the rapid rotation of the blades, distills air through the channels of the ventilation system. At the same time, it does not violate the process of natural air exchange, if it does not have a check valve.

When there is an unpleasant smell in the house, there is nothing to say about coziness and comfort.

Air fresheners will help prevent the situation, but often the problem is that the ventilation system does not work well in the room. In this case, bathroom exhaust fan is installed in places where unpleasant odors accumulate.

Duct diameter & duct connector

An obligatory part in the new bathroom exhaust fan is the air duct cubic feet. They come in different sizes and diameters. In modern homes, usually 4-6-cubic feet.

The air duct helps to increase the efficiency of the bathroom exhaust fan, and increases bathroom fan housing the speed of rotation of the blades.

There are also cases where there is a hole for 3-inch ducts, but rarely where to find such. In this kind of situation, you will be more convenient to buy a duct connector that fits 4 to 6 inch ducts.

But sometimes the duct connector reduces the performance of the air circulation exhaust process. The rotation speed of the blades may be less than that of conventional ducts.

ceiling exhaust fan in the bathroom

Additional fan wires & wall switches

Think in advance where and how you will connect and insert the bathroom exhaust fan. Because if there is no place in the bathroom where to connect the bathroom exhaust fan without attic access, then you will also have to think about wiring. Lay the system, thereby increasing the amount of work.

Where is it better to place the new exhaust fan?

In houses and apartments, the methods of running air indoors differ from each other. The complexity of the exhaust system directly affects the location of the bathroom exhaust fan without attic access installing. They can be located:

  • on the wall;
  • on the ceiling;
  • in the channel.
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The wall and ceiling hole bathroom fan (or overhead) is mounted directly. It is attached to the base of the ventilation shaft, which passes through the wall or ceiling hole barrier. There is also a mixed version when the hood works through the wall and ceiling hole at the same time.

A new duct exhaust fan is mounted in the ventilation pipe, and not in its base. Such a device can expel air from several rooms at the same time, for example, from the bathroom and toilet.

But ducted exhaust fans also have the disadvantage of inconvenient service. Access to them is usually closed, because the ventilation pipe passes behind the walls or ceiling joists of the room.

replacing a bathroom fan without access to the attic

How to install a bathroom fan without attic access: the 12-step guide

Installing or replacing a fan housing does not require any specific knowledge or special tools. Here are step-by-step instructions to DIY. So, the installation process starts with:

#1 Draw a new housing on the ceiling joists

This needs to be done so that you clearly understand how much space the exhaust fan takes up. This way you can protect yourself from mistakes and not cut off anything superfluous.

#2 Turn off the power in the bathroom

To protect yourself during repair work, turn off the professional electrician and all house wires in bathroom, because the exhaust fan is powered by professional electrician (beware bare wire).

#3 Remove the vent grille

It can be removed very easily, you only need to give it the edges for special holes and pull on yourself, then the lid will come off by itself.

#4 Remove the old fan assembly from the ceiling joists

First you need to separate the motor-existing fan assembly from the housing. The exhaust fan housing is attached separately to the ceiling joists. The motor-fan assembly is basically an insert. Some bathroom fans have an electric knockout plug in the housing to which the motor is connected. You will have to disconnect the motor from the mains before you can pull out the old exhaust fan housing assembly wood joists supports.

If there is no plug, the wiring will have to be disconnected manually, possibly by unscrewing the wire nuts after you have removed it.

removing the ceiling fan grill

#5 Remove the old housing from the beams

To do this, you need to remove the screws / nails / wire nuts that were used during installation, and then simply remove the disconnected house wires from the beams.

#6 Disconnect the duct and wiring from the old fan without attic access

When the housing is free from the ceiling joist, you may have to temporarily push the metal housing into the ceiling joist. As soon as it is lifted up, you will have access to the ventilation duct, which will need to be removed from the housing assembly.

You may also be able to remove the housing from the ceiling joist and then disconnect the duct. It all depends on the length of the duct. The duct is usually attached to the old bathroom existing switch fan with foil tape or a simple zipper that needs to be cut. After removing the ventilation duct, you will need to disconnect the electrical wiring of the house from the housing.

#7 Pull the duct through the new housing

Before attaching the new housing to the ceiling hole, you will need to remove the wiring cover on the new housing so that the wiring can be stretched.

After you pull the wiring through the housing, you must secure it with a protective sleeve or sleeve so that the wiring is not damaged by the metal edge. It is standard practice to use bushings (or bushings) to protect the wiring from friction against a bare metal edge. Your new exhaust new fan may or may not come with it.

#8 Attach the duct to the housing

The duct connector is a small plastic part that connects the duct inside the ceiling to the new fan in the bathroom.

The exhaust duct connector has a flap that closes when the new fan is not in use and then opens when there is an air flow. Always make sure that the duct connector is in the correct position, which means that the flap is closed when leveling.

#9 Fix the housing with beams

Do it according to the same principle as before they removed the old housing, only this time by screwing nails/bolts / wire nuts.

Connect the electrical wires of the fan

#10 Connect the electrical wires

Some new fan will have quick connections that allow you to insert bare wires into the wire connectors, which is very simple. Other exhaust fans will require you to twist the bare wires together and then screw the wire nut.

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After connecting the house wires, insert the wiring into the wiring cover compartment ground wire connectors and secure the wiring cover so that it does not interfere. Connect strictly according to the colors:

  • Hot wire (black wires to black or red to red)
  • Neutral wire (white wires to white)
  • Ground wires (green wires to green or green to bare copper).

#11 Reinstall the grille on the new housing in ceiling hole

Just attach it to the hole and press slightly, it will stand in position by itself. The main thing is to make sure that the holes match each other.

#12 Turn on the power and check the check if it runs

We hope that you got everything!

To check that nothing was missed, watch this video by The Home Improvement Channel:

Removing your old exhaust fan without attic access

Separately, let’s focus on how to dismantle an old exhaust fan, here’s a quick guide:

  1. Turn off the bathroom fan with the switch or in the automatic flap.
  2. Remove the wiring cover, press the spring-loaded clamps of the wire clamp located on both sides of the cover, and then pull the cable clamp out of the slots of the fan housing.
  3. Place the old fan cover on a towel and use a vacuum cleaner with a bristle brush attachment to remove dust from the wiring cover and grate, both inside and outside.
  4. Vacuum inside the fan housing and around the engine. For hard-to-reach places, use special vacuum cleaner nozzles.
  5. Install the new unit exhaust fan cover by simultaneously pressing the clips located on the bathroom fan cover and insert them into the slots on the fan housing. Put the fan back in its original place.

What tools may be needed during installation?

Installation of air ducts must be carried out by qualified specialists. This is due to many specific features, the installation of both the ventilation ducts themselves and the adjustment of the equipment that is installed in the active air supply system.

However, all those who decide to install a ventilation system in the room at their own risk should stock up on the necessary consumables and the necessary set of tools.

What you need to install the air ducts

Stock up on what you need so you don’t get distracted later:

  • Alcohol-based marker, it is useful for marking sections of air ducts;
  • Side cutters, metal shears, mounting knife, mounting flange, electrical tape or hvac tape (best hvac tape), wire duct connector, metal clips, keyhole saw, cable clamp – for the preparation of clamps, wire and perforated tape for the installation of air channels;
  • Puncher or punch drill, keyhole saw – for drilling holes for fixing air ducts;
  • A screwdriver or screwdriver is used to fasten the connections of the air channels, to attach the channels themselves to the wall or ceiling in the room or outside.

From the necessary consumables, a set of various sealants will be useful. They are needed to make the air ducts tight and in order to avoid foreign unpleasant odors and water vapor entering the duct cavity.

Dowel nails, fixing rods, perforated metal tape, sealing tape – this is just a small list of what you will definitely need when installing new fan ducts. It is necessary to listen carefully consider all stages of work, since depending on the geometry of the room and its features, this list can be significantly expanded and supplemented.

exhaust fan to remove excessive humidity

The main criteria for choosing vent fan

Manufacturers offer a huge range of fans for exhaust systems. Therefore, it is not surprising that every unprepared buyer falls into a stupor and does not even suspect that it is better for him to order.

When buying an exhaust device for the new bathroom and toilet, you need to pay attention to the following points:

The diameter of the duct

Depending on this characteristic, the fan nozzle is selected. As a rule, standard models have a diameter of 150, 125 or 100 mm.

The presence or absence of air ducts, as well as their location in the room. These criteria affect where the fan will be installed.


The characteristic is important when choosing so that in the future the exhaust equipment copes with the functions assigned to it. The greater the volume of air you need to remove per unit of time, the more power you will need from the fan. You can view some calculations here: Fan Capacity Diagrams.

If it turns out that the fan capacity is insufficient, you risk facing such an unpleasant phenomenon as black mold one day. Believe me, it’s very hard to get rid of black mold wherever it starts. More often than not, it happens in a bathroom on silicone caulk. For reference, see our post on How to remove mold from silicone caulk.

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The presence of protection from moisture

This indicator is marked with Latin letters IP. The minimum required value for a plumbing unit is IP30, but it’s better to spend a little money and order a device with IP44. In the latter case, it will be located in a special sealed casing, protected from moisture and splashes.

Noise level

Few people pay due attention to this important characteristic, but in vain. After all, a silent exhaust system will make being in the bathroom and toilet more comfortable. Imagine what the noise level will be if the washing machine and the fan are running at the same time, right? By the way, excessive humidity and pollution inside the washing machine are interrelated. Read the post about what to do if Samsung Washer Smells Bad.

Considering these subtleties, you can choose a model that will be inexpensive and satisfy all wishes.

exhaust fan capacity depends on the room

Chapter FAQ

Can you add bathroom fan without attic access?

The short answer is yes, you can add a bathroom fan without access to the attic. It is quite possible to replace a fan that is failing with a more powerful one. As a last resort, you’ll just have to increase the ceiling cutout a bit.

How do you vent a bathroom with no outside access?

There are many criteria that will help ventilate the bathroom without using windows. One of them is the fans in the bathroom, but sometimes their power is not enough. Then we recommend using the following steps:

  1. use portable fans;
  2. do not dry wet towels in the bathroom;
  3. use a dehumidifier (These nifty little devices can suck moisture out of the air and collect it in their tanks through condensation. And thanks to advances in technology, you can buy them at fairly low prices.)
  4. use a moisture absorber with humidity sensor (Just hang them in the bathroom, and every time there is excess moisture in the air, it completely and effectively absorbs it. It also absorbs odors and leaves the room clean and fresh. One package of dehumidifier will last for 45-60 days, depending on how often excessive humidity occurs in your bathroom.)

How do you replace a bathroom vent without attic access?

If you are replacing a bathroom vent and your home does not have access to the attic, you will either have to make a small cut into the attic or mount the fan on the exterior wall. It is best to install such a device before laying tiles. The sheet of plastic on which the cooler will be attached should be hidden in the wall under tiles or plastic panels. The work must be done as follows:

  1. Take the cooler and attach it to the sheet. Circle it along the contour.
  2. Cut a ceiling hole with a hacksaw. Trim the edges of the sheet at a distance sufficient to secure it to the wall.
  3. Screw the cooler to the cut-out ceiling hole.
  4. Connect the power supply to the switch and cooler.
  5. Check the operability of the device.
  6. Fix the invention on the wall with screws and screws.

Important! If the switch is not needed, the hot wire can be connected directly.

Is there a bathroom fan that doesn’t vent outside?

Yes, there is a bathroom fan that does not vent to the outside. This is called a recirculation fan. This type of fan puts the air in the bathroom through a filter to remove odors. But you should understand cfm stands that it is not too powerful a device to handle high humidity. In addition to a recirculation fan, a dehumidifier should be used.

What is the point of a ductless bathroom fan?

They also, like others, purify the air from unpleasant odors, harmful substances, and high humidity, like a new fan. Their main convenience lies in the cost-effectiveness and ease of installation. You will not have to suffer too long with wiring and any other elements.

bathroom humidifier


A fan in the bathroom is a necessary part of every person’s home. It greatly simplifies the care of the bathroom, as well as eliminates unpleasant odors, and removes excessive humidity.

You asked yourself the question of how to install recessed lights without attic access then we have answers.

We hope that you were able to find answers to all the questions in this article.

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