Buying guide for Best ventilation fans
A high concentration of moisture and condensation can make a room both uncomfortable and unhygienic. Mold and mildew are a direct result of too much moisture in a space. These fungi are unpleasant and unhealthy, and they threaten the integrity of your drywall, insulation, and even your roof beams.
Sometimes these dangers remain hidden until disaster strikes. Rectification of the problem then becomes a very expensive prospect indeed.
Fortunately, you can install ventilation fans in your attic, bathrooms, and other potential problem areas to prevent such problems. Even when fitted by a professional, a ventilation fan is an affordable home improvement that most, if not all, homeowners should consider.
Types of ventilation fans
We’ll discuss three common types of ventilation fans: exhaust fans, attic fans, and window fans.
Exhaust fans
The most common type of ventilation fan is an exhaust fan. These are generally used to remove excess condensation, moisture, and other vapors from kitchens, bathrooms, workshops, and so on.
Attic fans
The attic fan is an often underappreciated appliance that can prevent unseen damage and help your house 'breathe.” When considering an attic fan, it's worth looking into a solar-powered option to save you money on your energy bill.
Window fans
A window fan is technically a type of exhaust fan, though it may be reversible, drawing air in as well as expelling it. Some window fans are portable; you fit them to the window opening. Others can be used as cheap, albeit less-efficient, alternatives to air conditioners.
Expert Tip
Ventilation is one of the best ways to control air quality in your living space.
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Ventilation fan performance
There are two things that define the performance of a ventilation fan: the amount of air it moves and the noise it makes when doing so.
Air volume
The volume of air a ventilation fan moves is rated in cubic feet per minute, or CFM. 50 CFM is usually the minimum for a small space like a single-toilet bathroom. 140 or 150 CFM is considered a high level of performance for a ventilation fan.
There are formulas available for accurately calculating how many CFM you should have for a particular room, but here is a general rule from the Home Ventilating Institute (HVI): one CFM per square foot should work fine for most spaces.
Expert Tip
Ventilation isn't just about removing excess moisture. Fans also remove unpleasant odors, fumes from common household chemicals, and airborne pollutants.
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Noise output
Though sound is generally measured in decibels, the noise a ventilation fan makes is measured in sones. A sone equals 40 phons, and a phon is roughly equivalent to a decibel – sort of.
Confused? The problem is, a direct comparison can't really be made, because the increase isn't linear. Decibels work like a volume control in single steps: 1,2,3,4, etc. Sones go up exponentially: 1,2,4,8,16, etc.
Consider this comparison. One sone is similar to a quiet fridge. You can only really hear it if you're up close and listening. Levels of less than one sone are often classed as "whisper-quiet.” More than two sones would be clearly audible to most people. Feedback tells us most people think four sones is noisy.
Whether noise output matters to you or not will likely depend on where the ventilation fan is fitted. While a particular model might be considered intrusive if fitted in a bathroom adjoining a bedroom, it probably wouldn't be noticed in a family kitchen at breakfast time.
Did you know?
It's often difficult to tell if a quiet, low-volume vent is working. A quick and easy way to check is to hold a piece of tissue paper in front of it.
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Extra features
Some manufacturers offer other features to try to tempt you.
Two speeds
Two-speed ventilation fans render a higher performance, but that often comes at the expense of extra noise. You might be willing to put up with extra fan noise while you're showering but not at other times, for example. A two-speed fan offers you the option of tailoring the fan’s noise output.
"Although air volume (CFM) and sound level (sones) should probably have the biggest impact on your decision, style follows close behind. However unobtrusive the positioning of your ventilation fan is, you don't want to live with something you think looks ugly."
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Reversibility
Reversible ventilation fans are useful for basements and garages, giving you the option of bringing cool air into a stuffy environment.
Light
Some ventilation fans come with a light – either an ordinary bulb or a nightlight. Additional options allow for just the light to be working, just the fan, or both.
Expert Tip
The biggest mistakes people make when choosing a ventilation fan are not considering room size and getting a cheap, noisy fan that nobody wants to use.
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Heater
Another nice option is an infrared heater. Some ventilation fan heaters have timers so you can warm the room up in advance of your entry.
Automation features
Humidity sensors and on/off timers offer varying degrees of automation. If you’re looking for high-end sophistication, a ventilation fan with these features could appeal to you. Some fans even have motion sensors that can detect when a person is in the room. The fan will turn on (or turn up from a lower setting) based on motion sensor data.
Size and fitting
Photos of ventilation fans often make them seem smaller than they actually are. It's important to check the physical dimensions of your chosen model before ordering.
The majority of ventilation fans are ceiling-mounted. Wall-mount options are available for when you don't have access to roof space. (In this situation, you would likely have to vent sideways through an external wall.) Dual-mount options give you a choice of either position.
Fitting is usually straightforward and is done via some type of frame/carrier. These make it easy to mark the position accurately. You fit the carrier mechanism, then fix the fan to it.
Ducting is either four or six inches, though a few fans offer both. When possible, choose the larger option, as it improves air flow.
Electrical connections are relatively simple, but if in doubt, consult a suitably qualified electrician. If you're installing the ventilation fan yourself, always follow the manufacturer's instructions carefully. Caution is needed, because these devices are often fitted in moisture-rich environments – and electricity and water do not mix!
Caution
Beware of unusual ducting sizes. Four inches is common, but a few exhaust fans use six inches. Using smaller ducting than the fan is designed for will overwork the fan and reduce effectiveness.
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Ventilation fan prices
Inexpensive: Bargain basement ventilation fans have a reputation for unreliability and are frequently criticized for being too noisy.
Mid-range: Avoid the grief of a cheap ventilation fan with one that's reliable and HVI-certified which produces 50 to 90 CFM. A model like this can be yours for as little as $30 or $40.
High-end: In general with ventilation fans, you get what you pay for. But even the higher-end fans remain very affordable. Quiet, powerful models with 80 to 150 CFM tend to cost between $100 and $130. To add a heater or a light to that, you’d pay around $30 more.
Even top-of-the-range ventilation fans with motion- and humidity-sensing technology can be found for under $200.
Expert Tip
An attic fan doesn't just prevent problems. When you have windows open, it can draw fresh air through the whole house.
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Tips
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If you often need to leave the house before your bathroom is clear – and you don't want to leave your ventilation fan on all day – look for a model with a humidity sensor or a timer.
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On a warm day, your attic can be substantially hotter than the outside air. Installing an attic vent will let that hot air escape. This minor home improvement can save you money, as your AC won’t have to work so hard.
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If you work in your garage, a ventilation fan can make the environment safer and more comfortable. Of course, you should never run a motor in an enclosed space. But oils, paints, and other chemicals can also cause noxious fumes that need to be extracted. If you practice a craft or hobby in your garage, a ventilation fan will help improve the environment by preventing stale air and high humidity.
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HVI certification ensures that a ventilation fan has been independently tested and meets specific industry standards.
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Rigid ducting allows for more efficient airflow – and thus better ventilation performance – but it isn't always practical. Flexible ducting should be kept as straight as installation allows.
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Vent fans that include a heater should not be installed over a shower or tub. Other fans should be connected through a ground fault circuit interrupter, or GFCI.
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The HVI recommends that all enclosed bathrooms have their own exhaust fan.
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Energy Star-certified fans can be 60% more efficient than standard fans.
FAQ
Q. I have a large attic space. Is it OK to vent my bathroom into that?
A. No. However large, your attic is still a closed environment. Venting into it would trap moist air, causing condensation and encouraging mold and rot in your attic. Ventilation fans must always be vented to the outdoors, even if the attic is separately vented.
Q. Instead of running a separate vent, can I tap into an existing one, like the one for my cooker hood?
A. It's not a good idea to use an existing vent, because each one is specifically designed for the appliance that's connected to it. By increasing the air volume, you could actually overload the vent, causing condensation to fall like rain back down the ducting.
Q. In the winter, won't a ventilation fan mean warm air is leaking out the roof, thereby elevating my heating bill?
A. Your ventilation fan should have a baffle that is closed when it's not running. That way, warm air is only extracted when the fan is actually working. Vents are almost always used in situations where you're increasing the amount of warm air, anyway. The vent simply returns heat and humidity to a “normal” level.
If you left the fan running longer than necessary, there could be some heat loss, which in turn could add a few pennies to your heating bill. However, if you don't ventilate properly, you suffer personal discomfort and the harmful effects of condensation – which could cost you a great deal more.
