Do I Need a Humidity Sensor For My Bathroom Fan

A popular addition to a bathroom exhaust fan is a humidity sensor but what is it, what is its function and do I really need one? These are all great questions to ask. Lets take them one by one.

What is a Humidity Sensor?

A humidity sensor is a device that detects the humidity level of the room or surrounding area. You might hear them called humidistats or even dehumidistats. When is comes specifically to bathroom exhaust fans they are either located inside the actual fan or mounted on the wall. A wall mounted device will give a better indication of the overall room humidity where a sensor integrated into the fan will have a quicker response to a rise in humidity – especially when the shower is in use. When the sensor detects a rise in humidity it will turn the exhaust fan on until the humidity decreases. There are many factors that can contribute to how long that might take including items such as size of the room, how long the shower was on, how hot the water was, ambient temperature and so on.

What is the Function of a Humidity Sensor?

Removing the humid air is a key factor in increasing your home’s indoor air quality. If you allow the humidity level to stay very high (above 50%) items like mold and mildew will start to grow and if not mitigated can cause issues with rot as well as health concerns. If you notice a lot of mildew in your bathroom, paint that is peeling, or a musty smell, you probably have a humidity issue. A sensor is a built in way to monitor the humidity level of your bathroom and adjust accordingly without you needing to constantly be monitoring it. Sensors are able to be set for a wide range of humidity level usually from about 5% to 80% relative humidity. The lower the humidity level is set for, the longer the fan will run. The ability to set the humidity level allows you to adjust to your specific needs and geographic location. More humid climates will need to set the humidity level higher than less humid areas. A quick note. If the fan is continuously running, it might be because the normal humidity level is too high and air conditioning or some type of dehumidifier needs to be added.

Do I Need a Humidity Sensor?

As we stated above, humidity sensors provide an automated way to ensure the humidity level of your bathroom is where it should be. Sadly, the exhaust fans in many homes are not used properly or even turned on at all. It is recommended that the exhaust fan run for at least 20 minutes after the shower is turned off and that is in the best-case scenario. In more humid situations that time might go up to an hour or more. Having a sensor in place takes the guesswork out of determining if the humidity level of the room is where it needs to be. Considering if you need a sensor can be determined by answering the following questions:

Is my exhaust fan being used properly by everyone utilizing the bathroom? Is it being turned on and allowed to run for the set time needed to fully exhaust the humid air out?

Do I notice signs of mildew, mold, peeling paint that tells me I need more ventilation?

Are there any building codes in my area that require it? California CALGreen requires any exhaust fan in a full bathroom must have a humidity sensor.

Do I have a rental property? Having all the bathroom exhaust fans on a humidity sensor in rentals is a great way to ensure the fans are being utilized properly.

What to Do Next

If you are in the middle of a bathroom remodel or are looking to replace an old exhaust fan, this is a great opportunity to upgrade to one that has an integrated humidity sensor. If you already have an exhaust fan installed, adding a wall mounted sensor switch is a fairly easy way to ensure the humidity level of the room. We do caution that while this is a project most do-it-yourselfers can handle, if you have any questions or concerns to consult a license electrician. We also caution to make sure your exhaust fans can be used with a humidity sensor. All Air King exhaust fans are able to be used with a humidity sensor and in general most exhaust fan can be used with one, but there may be other brands that can not. One other item to consider when choosing an exhaust fan that will be used with a sensor is the sound level. Fans with sensors are most likely going to run for longer periods of time. If you have a really loud fan, this could cause a less than ideal situation. One of the main reasons people do not turn on the exhaust fan is due to the sound level. Look for a fan around 1 sone or less. These are very quiet fans and will probably provide a much better experience. 

For more information regarding bathroom exhaust fans as well as fans with integrated humidity sensors such as the BFC90H, visit airkinglimited.com. To learn more about a humidistat view our video on YouTube.

The 50 CFM Exhaust Fan Dilemma

We will admit it; most people are not staying up late at night thinking about their exhaust fans. For most homeowners, it is that thing in the bathroom that makes a lot of noise. The mindset is because it is making noise; it must be working – right.

Unfortunately, that might not be the case. The most popular fan size sold is a builder grade 50 CFM exhaust fan. These models are typically low cost which makes them attractive but they are loud and might not be doing the job they are intended for. Some of the issues come from the fact that they are installed in rooms that are bigger than their intended use. In an ideal situation (which never exists) a 50 CFM fan is good for a room about 50 square feet. In a real-world setting, it is probably closer to being able to handle a room between 35 and 40 square feet. If you have one of these installed in your bathroom, you probably notice things like the mirrors fog over when you shower and mildew seems to build up quickly. The good news is there are a few things that you can do. These vary from inexpensive to a bit of an investment.

1. Get on top of the situation. If you are buying a new construction home, talk to the builder about what they are installing. You might need to push a little, but it will be worth it. Sometimes you will hear things like “we put this fan in all our homes” or “we’ve been using this one for years”. That might be true but a little upfront work will save you money and headaches later. Many builders are also realizing that the old standby is not getting the job done and are already upgrading the exhaust fans. Also, make sure they are using a minimum of 4 inch ducting – 6 inch is even better and they are sizing the fan correctly. It is okay to oversize the fan a little. When we talk about a fan being able to handle a room X square feet – that is a minimum, not the maximum size.
2. Replace the existing one. Replacing an exhaust fan is a somewhat easy DIY project as long as you can access it from the attic. One issue that typically happens is a mismatched duct size. Most builder grade 50 CFM exhaust fans use 3 inch ducting. You will want to change that to 4 inch at a minimum. You can install a 4 inch to 3 inch reducer but that will decrease the airflow of the unit and cause the sound level to be higher. Definitely better to change the ducting if you can. If you are not sure about doing it yourself, licensed electricians or handyman can typically do this in an hour or two. To have a properly sized and functioning exhaust fan it will be worth the costs.
3. Let it run. If replacing the fan is not an option, extending the run time of the fan is the next best thing. Instead of turning the fan off as soon as you are done in the bathroom, allow it to run. The run time will be dependent on a bunch of factors. It might need to run for 20 to 60 minutes or more. Remembering to come back and turn it off might not be a practical solution. Installing a timer switch can be a good solution. An even better one is to install a wall mounted humidity sensor like the Air King DH55. These replace the wall switch and can usually be installed very easily (again, if you are not sure how to do this, contact a licensed electrician). It is also recommended you leave the bathroom door open to allow as much air exchange as possible to help reduce the humidity.

To learn more about Air King vast selection of exhaust fans and Indoor Air Quality Ventilation Systems, visit www.airkinglimited.com

Is the Air Inside Your Home Safe to Breath? Part 2 – The Bathroom

As we discussed in our last blog post, the air inside our homes can be up to 5 times more polluted than outdoor air. We also looked at the biggest culprit – the kitchen. In this post we will look at another one – the bathrooms. The bathroom has it’s own set of challenges when it comes to indoor air quality. The two main ones are moisture and odor with moisture being the main area of concern. While odors in the bathroom are unpleasant they in themselves do not present a health risk – they just stink and we want to get rid of them. The problem comes with using air fresheners. In order to rid the room of the smells, we spray a chemical agent into the air that we in turn breath in.

Moisture presents a whole other set of challenges. There is no way around it, if you take a shower or a bath, you will have moisture in the bathroom. Anytime there is moisture, there is the potential for mold and mildew to grow. Once that starts, the air you are breathing now has the potential to be dangerous. Now before everyone goes crazy and starts wearing HAZMAT suits in the bathroom, a lot of mold and mildew can be eliminated with a consistent cleaning routine. What we want to focus on is reducing the route causes. The good news is whether it is odors, mold or mildew, the solution is the same – good ventilation. Good ventilation has multiple components to it all working together. They include:

Vented to the outdoors: The air needs to leave your home. You sometimes will see the exhaust fan vented to the attic or just inside a wall. All that is happening in this scenario is the hazard is being displaced. Instead of the mold growing in your bathroom, it will now be growing in the attic or inside your walls. At least if it is in the bathroom you can see it and might be able to mitigate it before it gets out of control. In the attic or a wall, you won’t have that benefit.

Power: Another mistake many people make is trying to save a dollar or two and installing a fan that is not sized properly. If your mirrors fog up every time you take a shower, your exhaust fan is probably undersized. When sizing a fan, you want at least 1 CFM per square foot of space.

Make sure it is turned on: The biggest complaint when it comes to exhaust fans is how loud they are. Technology has come a long way and now there are fans on the market that you can barely hear running. All of Air King ENERGY STAR® certified exhaust fans operate at quiet to almost silent sound levels. Another solution is to use a fan that automatically turns on such as one with a humidity and/or motion sensor. These are great if you have children or guests that are not as reliable when it comes to turning the exhaust fan on.

Keep it running: To make sure you are properly exhausting the room it is recommended that the fan run for at least 20 minutes after it has been vacated. Adding a timer is a perfect solution. These can be a part of the fan itself or as a wall switch.

To learn more about Indoor Air Quality and how you can properly ventilate your home, visit www.airkinglimited.com.

Wait, I have an exhaust fan in my bathroom? Are you using your bathroom exhaust fan correctly?

Hopefully you not only know you have a bathroom exhaust fan, you are also utilizing it every time the bathroom is occupied. The main function of an exhaust fan is to clear unwanted contaminates such as moisture and odors from the bathroom. For a lot of people that means that when the mirror starts to fog up, they turn the fan on and as soon as they leave the room they turn the fan off.

Unfortunately that is not utilizing your fan the way it is designed. According to the Home Ventilation Institute (HVI) the exhaust fan should run for at least 20 minutes after the shower has been used. This ensures that the proper amount of ventilation has occurred. To simplify the process there are many timer options on the market today.

For existing fans, you can simply add a timer wall switch. This can typically be done in less than an hour by a homeowner with some electrical wiring knowledge. Air King always recommends consulting a professional if you are unsure about any aspects of the installation.

If you are looking to purchase a new exhaust fan, there are many models that include motion sensors that detect when you leave the room and allow the fan to run for the preset amount of time. Both of these option simplify the process so you are not trying to figure out how long the fan has been running or need to remember to go back into the bathroom to turn the fan off. To learn more about Air King’s bathroom exhaust fans, visit www.airkinglimited.com