Q&A / 

Bathroom Exhaust Fans

bathroom exhaust fan attic

The off-white, overweight flying saucer is really a quiet bathroom exhaust fan. You can see the flexible insulated exhaust pipe that prevents condensation. The humid bath air goes out the roof. © 2017 Tim Carter

Bathroom Exhaust Fan TIPS

DEAR TIM: I have several inexpensive builder-grade exhaust fans in my home. They're noisy, and I don't feel they do a good job of getting rid of the moist air produced while showering.

Is it possible to get high-performance ventilation with little or no noise? I'd like a bathroom exhaust fan with a light.  How about a fan that has a light and bluetooth speakers?

Can you tell me how to install a bathroom fan so I do not cause any damage to my home? Faith F., Mt. Crawford, VA

DEAR FAITH: Bathroom fans are a critical part of a home-ventilation system. A bathroom exhaust fan, improperly installed, can create all sorts of hidden damage to a home.

All too often, installers just let the moist air escape into an attic space. This moist air can condense on the cooler surfaces in the attic. This liquid water on the wood surfaces creates mold and can lead to serious wood rot.

CLICK HERE to get FREE & FAST BIDS from local bathroom exhaust-fan contractors.

Great Fans

The good news for you is that the exact fan you are looking for is available. It's been around for years, but many builders choose to install cheaper fans to try to make their houses more affordable.

The trouble is, I've discovered many consumers would gladly pay a slight up-charge if they were given the option of having great ventilation and less noise while in the bathroom. It's my hope that builders start to learn to offer home buyers more choices.

But I feel that day may never come, as builders will argue that more choices equate to more problems for them.

Up In The Attic

I've had fantastic luck installing bathroom exhaust fans that are actually located in the attic space. They resemble central vacuum systems inasmuch as the fan motor is located perhaps 8 or 10 feet away from the bathroom. Most builder-grade fan motors are just inches away from the bathroom ceiling. This is one reason why they're so noisy. Refer to the photograph at the top of the column.

Flexible Insulated Pipe

These remote bathroom exhaust fans have insulated flexible duct pipe that extends from the fan motor to small exhaust inlet boxes that are attached to the framing members in your bathroom ceiling. The box extends up into your attic, and all you see on the bathroom ceiling is a sleek round inlet cover.

The powerful fans can slurp up massive amounts of moist humid air that rises to the ceilings as you shower. This air is ducted through the roof of your home in a special roof vent cap that is easy to install.

Vent Through Roof

I've found that it is often best to vent fans and dryers through the roof. I'd only recommend this in areas that get very little snow in the winter. If you live where snow can be heavy in the winter, then vent your bath fan out a side wall well away from a roof overhang.

IMPORTANT TIP: NEVER vent a bath fan into an attic space or under a roof overhang. Both of these situations will produce vast amounts of black mold in the attic.

CLICK HERE to get FREE & FAST BIDS from local bathroom exhaust-fan contractors.

Roof Bath Fan Flashing Video

Watch the video just below to see how easy it is to install the correct vent-cap flashing on a roof. Have no fear - if done right you will have no roof leaks.

Insulate Exhaust Pipe

The flexible insulated ducting that extends from the roof to the remote attic exhaust fan, and then to your bathroom ceiling, does two important jobs:

  • Suppresses noise from the fan
  • Prevents condensation from forming inside the flexible piping

False Fan Leaks

Many people complain about water that drips down from their bathroom fan in the winter. They think they have a roof leak.

If it were a roof leak, the water would drip all year every time it rained.

If you have a winter-only leak like this, then it's not a roof leak but condensate water that forms inside of uninsulated exhaust piping and flows down the piping into the bathroom.

LED Lights and Fans

The bathroom exhaust fans I use come with or without lights. The ones with lights use brilliant compact halogen or LED bulbs that fit into the center of the small circular vent covers.

Here's a typical Fantech bath exhaust fan setup. The odd cone-shaped metal thing is the fan. The two boxes that have the round white covers are place up in the ceiling joists of the bathrooms. All you see are the sleek round white covers. They come with and without lights! I LOVED these in my last house. CLICK THE IMAGE TO BUY the SET NOW.

Two Outlets Per Bath

I always place two of these inlets with lights in each bathroom, one immediately adjacent to the shower area and the other toward the center of the bathroom. These lights produce good overall lighting for the average bathroom.

You'll need additional lighting above or on the sides of any mirror.

Bluetooth Music Exhaust Fans

How would you like to listen to your favorite music while in the shower or otherwise occupied in your bathroom? While the whisper-quiet fan is vacuuming air out of the bath, music plays from great speakers under the decorative trim.

It's all done with the magic of bluetooth radio waves. CLICK HERE to get the Broan Bluetooth fan I've got in my own basement bathroom.

underside of the rough fan housing

This is the underside of the rough fan housing. It looks ugly. See that odd squat U-shaped thing at the bottom? Those are two powerful stereo speakers. You'll love this fan. CLICK THE IMAGE NOW TO ORDER ONE.

Read Instructions

To avoid damage to your home while installing a bathroom fan, always follow the written instructions that come with the fan. If you're not comfortable working with high-voltage electric wire so it will pass inspection, then hire a competent electrician to connect the fan.

The most important aspect is to duct the air from the bathroom to the exterior of the house. You should do this through the roof so long as you don't get lots of snow on your roof.

Never Soffits

Avoid the temptation of venting your fan through the horizontal soffit that can be found in many roof overhangs. All too often the moist air billows up under the soffit and is sucked into the attic. If this happens, mildew and wood rot up in the hidden spaces of your attic is a certainty.

Down-the-Road Defects

Problems with bathroom exhaust fans can happen years later. The connections between the flexible duct pipe, the fan, inlet boxes and the roof vent cap must be permanent. Never rely on duct tape to secure these connections.

The high heat and humidity in attics can cause duct tape to fail. It is better to use metal band clamps that are nearly identical to traditional automotive radiator hose clamps. These inexpensive clamps can be found at hardware stores, ductwork shops and some home centers.

Once the band clamp is connected, then use tape as directed by the fan manufacturer.

If you use solid galvanized pipe to duct your fan, then use self-tapping screws to connect the sections of pipe.

No Kinks

Be sure there are no kinks in the flexible duct pipe. Also be sure to install a makeup air duct in your home that allows an equal amount of fresh air to enter your home for every bit of air the exhaust fan is expelling.

If you don't have this critical makeup air, you could cause "backdrafting" to occur. This means poisonous gases are drawn into your home through furnace or water heater exhaust pipes.

CLICK HERE to get FREE & FAST BIDS from local bathroom exhaust-fan contractors.

Sandra emailed me and asked an interesting question about her bathroom exhaust fan. CLICK HERE to read her question and the answer.

Column 665


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