Bathroom Remodeling Ventilation Solutions


Bath fans can play a key role in a home’s indoor air quality (IAQ), by exhausting moisture automatically or continuously. 


The bath fan is rarely the first thing that comes to mind when people think about remodeling their bathroom. Steam showers, jetted tubs, marble tile, and fancy fixtures usually take center stage.

But the exhaust fan can easily be the most important decision you make when planning a bath remodel — and not just because steam showers and jetted tubs release a lot of moisture into your house.

As houses get tighter, clearing the air of contaminants becomes critical for good indoor air quality and the durability of your wall finishes.

If your clients plan to weatherize or upgrade the insulation and airtightness of their home anytime soon, then it is important to plan a ventilation strategy now so they (you) won’t have to open up the ceiling and walls again later on.

The lowly bath fan can play a key role in a home’s indoor air quality (IAQ) by exhausting more than one room at once, controlling moisture, operating automatically or quietly and continuously running at a low level. Because bathrooms create so much moisture in a home, it is important to quickly exhaust the moist air to the outside before it condenses on the walls, ceiling, and windows.

Duct layout and fan sizing are first steps

Efficient air movement means a properly sized fan, a short duct run, smooth-walled ductwork, few or no elbows in the ducting, and a damper that doesn’t restrict airflow. Typical bathrooms need a fan that can exhaust 1 cubic foot of air per minute (cfm) for each square foot of floor space. A single 100 cfm exhaust fan can handle a typical 100 sq. ft. bathroom with no separate water closet or jumbo jetted tub.

More complicated bathrooms require more fans: one for the water closet, one for the jet tub, one for the shower, etc. The size fan that you need may increase for complicated duct runs.

Retrofitting ductwork can mean longer runs

Efficient exhausting is even more challenging when part of a remodel because you don’t always have the flexibility to put the fan where you want to. Duct runs may need to be longer and have more elbows in a retrofit design than they could be in a new-construction design. Available space above the ceiling could also be a concern as many fans on the market are too deep to fit in some ceiling cavities.

For these reasons, ductwork should be considered early in the design process. Consider these questions:

  • Can you slip the ductwork into the ceiling framing for a direct run to the outside, or will you need to run the ducts perpendicular to the framing within a dropped soffit?
  • If you add a dropped soffit, how will it blend with the rest of the room?
  • Can you run the duct straight up and through the roof? Maybe a wall-mounted fan will need to do the heavy lifting.

These simple decisions can really throw a wrench into remodeling plans if not considered early in the process.

Controls and sensors can add design flexibility

After figuring out fan placement, fan size, and duct layout consider how the fans will be operated—manually, automatically, semi-automatically, or continuously. The answer depends on what you want to achieve with your whole-house ventilation strategy.

And this answer may change over time—after you weather-tighten the house or after the kids move to college, for example.

Condensation sensors go beyond humidity sensors or timers by clicking on before dew point is reached and clearing humid air quickly.

Motion sensors can allow a fan to operate only when people are home, which can help save energy.

With the right fan, a clear exit strategy, and versatile control center, a quiet little bath fan can make a big splash in clean indoor air and home comfort.


Panasonic’s Ventilation Solutions Center:

Panasonic has many fans to solve your remodeling ventilation needs


WhisperGreen Select: The Best. Fan. Period.

You have complete control over this customizable IAQ solution
WhisperGreen Select™ just jumped ahead of the pack in ventilation solutions. Our best fan now delivers an array of solutions for almost any application.

Customizable all-in-one fan and fan-light combinations give you more than 250 possible configurations: multiple flow rates, plug 'n play modules, and installation flexibility means that WhisperGreen Select™ is your total solution for indoor air quality, code compliance, green certification, and healthy indoor environments. 


WhisperFit EZ installs easily

The low-profile design fits existing holes to replace defective fans in a 2x6 ceiling or dropped soffit. You won't have to replace ductwork or buy extra conversion kits because WhisperFit®EZ fans come with adapters that can incorporate 4 in. or 6 in. ducts.

The double hanger-bar system (expandable up to 24 in.) is ideal for positioning the fan exactly where you want it. And no rewiring because these fans are simply designed — one switch for WhisperFit®EZ.  


WhisperComfort: The High Performance, Low Cost Solution for Balanced Ventilation

The best ventilation solution for a tight house is a ventilation system that balances air pressure in the home. Designed to run continuously at a low CFM setting WhisperComfort exhausts stale air, moisture, and indoor pollutants, while bringing in fresh, clean, tempered air from outside.

WhisperComfort cleans the air in the process making it an ideal choice for a single-room or as part of a whole-house indoor air quality strategy. 



WhisperWall: Installation Flexibility That Pays

The ability to install a vent fan in a wall means that you can eliminate a complicated duct run and maximize the efficiency of your bath fan. The super-quiet WhisperWall is Energy Star rated to help you comply with green certifications and save money to boot. 


WhisperControl: Add Control to Improve Indoor Air Quality

Beyond simple on-off switches, ventilation control devices allow you to fine-tune a whole house ventilation strategy.

Sensors can detect condensation before it becomes a problem. You can add manual switches for even more control. 

WhisperControl Condensation Plus detects and balances relative humidity and temperature to avoid condensation problems. A Sensitivity selector allows you to control based on the season and climate (humid, average, or dry). The fan turns off when conditions balance. An LED indicator light lets you know the status. 






— This article is by PanasonicIAQ, one of ProTradeCraft's advertisers. #PanasonicIAQ is the premier manufacturer of powerful, energy-efficient ventilation fans that quietly exhaust unhealthy, unpleasant or moist air from home or business. See all of PanasonicIAQ's content here.



It's nearly impossible to find well-informed people for this
subject, however, you sound like you know what you're talking about!

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