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Choosing A Bathroom Fan

Choosing a bathroom fan doesn't have to be difficult and you might think that they're pretty much all the same. However despite the seeming similarities among them, there are differences and ones that go beyond just aesthetics.

If you're reading this page you probably don't need to be convinced of the need for good bathroom ventilation. Once you're beyond that point however you'll need to determine the size of the fan your bathroom requires. There are guidelines to help you figure this out so don't fret if you never studied fluid dynamics.

Other factors you'll need to consider include the fan's sound volume, energy efficiency and whether you need a new fan or just an upgrade kit.

There are good bathroom fan choices on the market today that are much better than their old predecessors. It's just a matter of matching your home's ventilation needs with your preferences.

Why Do I Need A Bathroom Fan?

Bathroom fans are important particularly in bathrooms with showers and tubs because the moisture and humidity that's generated there isn't good for your home. The best and most effective way to get rid of that moisture is to install and use a bathroom ventilation fan.

If you don't have any bath ventilation or you just don't use it you know what it's like when you step out of the shower. The mirror's fogged up and the walls and countertop have a moist coating.

The problem with all this moisture is that it can lead to the growth of mold that's both unhealthy and can damage your home. Constant exposure to moisture is also detrimental to some of the materials in and around your bathroom. Getting rid of the moisture as it's produced is the best defense against the problems caused by excess wetness.

Another reason to use bathroom ventilation is to help improve your home's indoor air quality. Odors and indoor pollutants become more prevalent in "tight" houses that are built or remodeled to be more energy efficient. They're not as "leaky" as older houses and without proper ventilation, these contaminants remain in the house longer. A bathroom fan helps to eliminate some of these pollutants by providing a ventilation outlet.

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What To Know & Look For

Choosing a bathroom fan involves knowing how to properly size the unit for your space in addition to what preferences you have regarding its operation. Before we get into the details let's take a look at the 3 main types of bath fans that you can install.

Types Of Bath Fans

Ceiling Mounted - ceiling mounted fans are installed in the ceiling at specific locations where they'll be most effective at ventilating the space. Since they're closest to the living area you'll hear them more than the other two types listed below. However there are many ceiling mounted bath fans that are very quiet and a far cry from the fans of old.

Inline (Remote) - Inline fans are also called remote bath fans because the fan unit is located in an area away from the bathroom, typically in the attic. There is an opening in the bathroom ceiling covered by a grille that is ducted to the remote fan. Another duct runs from the other side of the fan to the vent outside the house.

An advantage of inline bathroom fans is that one fan can be connected to several inlet ducts located in different areas of a single bathroom or to inlets in different bathrooms. If you have two upstairs bathrooms for example, one inline fan can ventilate both bathrooms, avoiding the need to install a fan unit in the ceiling of each bathroom.

Wall Mounted (External) - A wall mounted bath fan is mounted outside the house on an external wall just outside the bathroom, instead of being inside the bathroom or an attic. These bath fans work best in situations where there is no access or practical way to vent through the roof. They also work well for first-floor bathrooms particularly if they're situated near an outside wall.

One caution is that these fans shouldn't be located close to a window or a vented soffit since the moist air that's being evacuated can come right back in through these places.

Choosing The Right Bathroom Fan

Once you decide on the type/location of the fan you'll want to look for how various fans compare relative to the following points.

  • Fan Rating/Capacity
    The fan needs to be the right capacity for the size of the bathroom that it's ventilating. The Home Ventilating Institute (HVI), a non-profit organization representing the ventilation product industry and chartered with maintaining industry standards, recommends that for bathrooms up to 100 square feet, the fan should "move" 1 CFM (cubic foot per minute) per square foot of area.

    For example, a 5'x8' bathroom equates to 40 square feet. A proper fan for this space would be one rated at 40 CFM.

    For bathrooms larger than 100 square feet the HVI recommends ventilating based on the number and type of fixtures that are in the bathroom. Toilets, showers, and bath tubs each require a fan rated at 50 CFM. A whirlpool tub requires a fan rated at 100 CFM.

    For example, if your bathroom is larger than 100 square feet and you have a tub, shower and toilet, your total requirements add up to 150 CFM (50 for each fixture). You can use a fan rated at 150 CFM or install 3 separate fans rated at 50 CFM over/near each fixture.

  • Energy Efficiency
    Depending on your particular needs and use patterns your bathroom fan might operate for a good chunk of the day. You have the option of choosing fans that are more or less efficient based on the particular product and features you want. Fans marked with the U.S. Energy Star logo meet current efficiency standards and will use less energy than those that don't have this rating.

    If you live in California, you'll need to comply with Title 24 energy requirements. Title 24 is part of the California Code of Regulations dealing with the establishment of energy efficiency requirements for residential and commercial buildings. The standards change periodically as newer technologies and advances in energy efficiency are developed. Bathroom fans that meet these criteria are noted as such.

  • Sound Level
    Bath fans are also rated on how much sound they produce. Fans of old sounded like your bathroom was actually a helicopter about to take off. However improvements in motor and fan design have really helped reduce the wind tunnel effect.

    Bathroom fan sound is expressed in sones and a sone is simply a measure of loudness. For example, 3 sones is louder than 1 sone which is louder than 0.3 sones.

    There are fans on the market today that only get as loud as 0.3 sones which is pretty quiet. On the other hand there are also fans that are in the 2 to 3 sone range. Consider the sound rating of the fan before you make a decision. Some big-box home centers have displays that allow you to hear the difference between various fan sound levels.

  • Choose The Type Of Control
    Bath fans can be controlled by a simple on/off switch and they can also be programmed to automatically turn on and off when you need them to. Think about how you want the fans to be controlled and what will work best for your particular situation.
  • Choose A Bath Fan Upgrade Or New
    Old and noisy bathroom fans can be fixed by either replacing them outright or by installing a bath fan upgrade kit.

    The first option involves using a fan upgrade kit for celiing-mounted fans made by the manufacturer of the old fan unit (for example, a Broan upgrade kit that retrofits an existing Broan fan). In this scenario the fan upgrade kit comes with a new fan and grille. Since the aerodynamics of the fan is what make most of the noise, newer technology fans are what help achieve quieter operation.

    The second upgrade option involves getting rid of a ceiling mounted fan and replacing it with a remote inline fan. These kits come with the inline fan and the ductwork necessary to attach the grille opening in the ceiling to the fan and then up to the roof vent. In this type of retrofit you keep the grille from the old fan and use this to cover the opening in the ceiling. This option is a good solution for those wishing to get rid of their ceiling fan and move the fan to a more remote location.

When it comes time for installation you can choose to install the fan yourself or hire someone to do it for you. The job is not out of the realm of someone that's fairly handy but there is electrical work involved. And if this is a completely new installation (where no fan and/or ductwork previously existed) there will be ductwork that'll need installation too.

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Features & Options To Be Aware Of

Today's bathroom fans are miles ahead of their dinosaur ancestors. Technology advances have led to quieter fans with very good energy efficiency. Here are some of the key product innovations and options to look for.

  • Fans With Lighting
    Bath fans with lights have been around a while but if you're not a fan of the square-ish plastic looking bath fan light, opt for a recessed fan light. A recessed fan light looks just like a typical recessed light you'd find elsewhere in the house except that it's a ventilation fan as well. This option might blend well in a bathroom that uses other recessed lights in the ceiling.
  • Energy Star Rated Bath Fans
    Having one or several bath fans running for a portion of every day doesn't have to eat into your utility bills. Look for bath fans that carry the U.S. Energy Star label for units that will be more delicate on your electricity bill.
  • Decorative Light Models
    We mentioned lighted fans above but there are other models that look (and perform) like a typical domed ceiling light. The trick is in the metal trim around the base of the light. The slotted trim is actually the grille for the fan. Again, if you don't like the look of typical bath fan grilles, try out one of the domed light fans.
  • Heater & Fan Combinations
    Some manufacturers like Air King combine heaters into their fans. While the fan sucks away the shower steam the heater can make stepping out of that shower a bit more comfortable.
  • Motion & Humidity Detection
    Fans that detect either the amount of moisture in the air or motion in the room take the burden out of having to remember to turn a fan on or off. That's especially helpful with kids who couldn't care less about making sure the bathroom fan is on when they shower and off when they leave.
  • Timers
    In actuality bathroom fans should continue to operate for a while after someone takes a shower because all that wetness on the shower walls and doors eventually evaporates. Fans with built-in timers can be set to stay on for an amount of time that you specify before shutting off.

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What Should I Consider Before Choosing One?

The information above gives lays out the criteria for choosing the right bathroom fan. But before you make that final decision, make sure you've considered the following items.

  • Follow The Guidelines For Sizing
    Installing a fan that's too wimpy (doesn't exchange enough air) for the size of the bathroom won't get rid of the moisture. Choosing a fan that's too powerful takes away conditioned air (either heated or cooled air). Thinking that "more is better" isn't valid in this case.
  • Remote Fans
    Some remote fans that connect to more than one bathroom are controlled by one source meaning that when it's on in one bathroom, it's on in the other/all of them. Not all fans are like this as some do have the ability to sense which locations need ventilation. However be aware that this difference exists among remote (inline) fans.
  • Make Sure It Exhausts Outside
    Remember that the reason you're getting a bathroom ventilation fan is to get the moisture and bad air out of your house, not just out of the bathroom. Make sure the fan exhausts the air outside the house and not in the attic or some other dead space inside the envelope of the house. Doing so only "moves" the potential moisture-related problem someplace else in your house.
  • Ductwork In Attic Should Be Insulated
    The ducts that connect the ceiling fan/grille to the outside vent through an unheated attic should be insulated. This ensures that you won't have water dripping back out of the fan vent. Uninsulated ducts cause steam and moisture-laden air to condense back into water once it contacts the colder ducts in the attic.
  • Consider The Switching Carefully
    For a bathroom fan to be effective it needs to be turned on. If you're diligent enough to always turn it on and off after you, the kids and the dog are finished showering, great. Otherwise think about motion sensing units or fans with humidity controls or programmable switches that automate the process so you don't have to become the fan police.

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Publisher's Comments

I lived in my home for a very long time with no bathroom exhaust fans so I know what it's like not to have good ventilation. To be honest, one of our upstairs bathrooms did have a fan but it was ducted into the attic. I promptly disconnected that one.

The master bath didn't have a fan either but I resigned myself to living with wet mirrors and walls. Why I did that I don't really know but maybe it had something to do with the fact that for a while my wife and I were the only ones taking showers.

As my three sons moved from toddlers into full-fledged shower hogs the amount of steam and moisture that gathered in and around the bathrooms rivaled a good London fog. When the hallway and bedroom windows started dripping, I knew it was time to take action.

When we remodeled our home I took advantage of the presence of electrical and HVAC contractors and had them install a fan in each bathroom. I chose the type of fan I wanted and they did the rest, installing the fans and ductwork and wiring them up.

Incidentally, I did have some mold problems. It wasn't severe but it was there. Who knows how much worse it would have become if we had left things status quo. Now there's no more fog and no more dripping windows, even when my 3 shower hogs..er..children have finished their bathing marathons.

Bottom line message: if you don't have a bathroom fan, you'd be wise to invest in one.

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Here's More Related Info That Might Be Helpful...

Bath Design Ideas - A great bathoom design is actually a compromise between two key elements (and a bath fan is one of them).

Steam Showers - Bath fans are necessity when your bathroom has a steam shower. Discover how to add a bit of luxury to your bathroom in this article on choosing steam showers.

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