However, to have a whole house fan that delivers the best results, you have to design your home properly with the right vents and the right layout.
Ventilation in a Home: Does it Matter?First, it helps to understand the benefits of ventilation. Consistent ventilation through a home provides many different benefits, including comfortable, cool air. However, ventilation also has benefits for overall health and well-being.
A research project from Berkeley Labs looked at numerous individual studies involving ventilation and overall health. Just over half of the studies found a statistically significant connection between health and increased ventilation. While not all studies showed a connection, there appears to be at least a minimal connection between health and ventilation. This health benefit could come from many factors.
For example, ventilation helps move dust from the air and pushes it outdoors, creating less chance for dust allergies. Ventilation could also move viruses, bacteria, dangerous gases and chemicals plus particulate matter, which could all increase the chances of health problems. Think about the cleaning supplies in your home. It is helpful to ventilate the related fumes out of your home.
A paper from the International Journal of Ventilation recommends at least 0.4 air changes per hour. Anything below that, the paper claims, will increase the risk of health conditions. It appears that as long as you have some ventilation, you’ll avoid the negative consequences of no ventilation, but increasing ventilation to extreme rates will have no noticeable benefit.
Air Conditioners are Not Whole House FansMany people get whole-house fans confused with air conditioners, so it also helps to explain the difference, as it will impact both the quality of the air in the home as well as the energy usage.
Air conditioners use a refrigerant that chills air and releases it through vents into the living space of a home. Air conditioners exploit the fact the when a liquid is converted to a gas, it absorbs heat. Using this principle, air conditioners force special chemical compounds that evaporate and condense over and over again, continually absorbing heat. They also contain fans that push the air through a series of ducts, allowing you to cool your home.
When the outside temperature is hot, using an air conditioner is often the best choice. However, if the outside air is reasonably comfortable enough to open the windows, a whole house fan system can increase home comfort with less energy.
Whole-house fans are essentially fans placed in the ceiling of your home. They move air through the home and create a gentle breeze that can help keep the house cool. Unlike air conditioners, whole house fans need open windows, as well as vents in the attic, to operate properly.
Whole house fans are also different from attic fans, which merely circulate air in the attic.
Signs of Poor Ventilation in Your HomeIf you have poor ventilation in your home, it could cause a problem with your air quality. Having the right air quality will help with the overall health and well-being of everyone living in the home.
One sign of poor ventilation in the home is increased humidity. Humidity levels that are too high or too low cause discomfort, but they can also make the home more likely to have issues with mold. Excess moisture, which is not being removed through ventilation, can be an issue for your home because it causes mold, as well as insects that feed on mold.
Ventilation, however, helps move moisture through the home and ensures more comfort and a cleaner household.
You could also experience excessive dust if you have low ventilation. Just like the moisture, dust can be removed through a slight breeze in the home. If you notice excessive dust, you may need to consider enhancing the ventilation in your house.
Poor ventilation can also result in inconsistent temperatures from one room to another. If air is not moving easily through the home, it may be hot on one side of the house and cool on the other.
Finally, odors are a concern if you have poor ventilation. From old socks to smelly bathrooms to dirty pets, a full house can generate a lot of smells, but ventilation helps clear the air, providing a refreshing breeze that make the entire home more enjoyable.
How Many Air Vents Does a Home Need?Ventilation is an important part of using a whole-house fan. By allowing the air to flow outward through vents in the attic, you create a smooth flow of air that can help increase overall air quality. However, the amount of vents you need will vary depending on many factors, including the size of your house, the strength of the fan, and the size of the vents you are installing.
First, you will need to know the air volume of your home, which can be calculated by measuring the space, in cubic feet, that is located in the living space of your house. Once you have the air volume, you should multiply the amount by 30. Divid that number by 60 and you have a number that represents the Cubic Feet per Minute of your home. This number is often referred to as the “CFM”.
You will need a minimum of one square foot of attic ventilation for every 750 CFM. For example, if you have a CFM of 6,000, you’ll need eight square feet of ventilation.
Some vents only give you one square foot, while others may give you four or more. You can also mix-and-match them, as long as the total square feet matches your required number.
Does Floor Plan Matter for a Whole-House Fan?The more open, spacious, and uncluttered your home is, the better the whole-house fan will perform. For example, if you have a home with numerous walls, decks, book shelves, and closed doors, the air will not be able to flow as freely as is should.
Think of air flow in the home as a river. The more obstructions you have in a river, such as dams, rocks, and logs, the slower the water will flow from one point to another. The same principle applies to air. The “river” of air is slowed when it has to go around tables and walls, and this can mean that your whole home fan will be less efficient and will have to work harder to maintain high-quality air flow.
So how can you improve the performance of a whole-house fan?
First, let’s assume you have the chance to design (or redesign) the interior layout of the home. If whole-house fan performance is your goal, you’ll want as many open spaces as possible, with fewer turns and angles that could slow the air flow. An open kitchen/living-room layout, for example, is a good way to increase the air flow for a whole-house fan.
Obviously most people will not have the opportunity to design their own layout. However, there are steps you can take to increase the efficiency and performance of your whole-house fan without knocking down walls.
Start by keeping as many interior doors open as possible, especially the ones with open windows. It would not make sense to run the whole house fan but close the doors between the source of air and the attic. In fact, it could create a dangerous situation if gas is pulled backwards into the home instead of out the right vent, which can happen if there is negative pressure.
To increase the quality of air flow in your house, keep the home as open and uncluttered as possible. You may need to downsize your furniture selection so the air can easily flow from the windows to the whole-house fan and out the attic vents, and be sure that no furniture is blocking the windows.
With the right home design for a whole-house fan, you’ll get better performance and better comfort.
Is Noise Reduction Required?Noise reduction is generally not a major concern for whole house fans, but as you move into higher-powered units, you may find that they are a little too loud. However, there are a few home-design steps that you can take to reduce noise levels from the fan. Most whole-house fans use advanced technology to dampen the noise inside the unit, but sometimes you need to take steps that dampen noise outside of the unit as well.
First, if noise is a concern, then choose a stronger whole-house fan and run it on a lower fan speed. Also, consider a whole house system with an energy efficient EC motor (as opposed to an AC motor). They are more reliable, use less energy and are quieter.
You may find that simply tightening the bolts and screws in a fan could reduce noise. If the fan is older, some of the screws may have been loosened through years of use. Installing washers can also ensure quieter performance.
Insulation can also be used to reduce noise from a whole-house fan. Much of the noise can be due to vibrations, but insulating the surrounding area can keep it stable and reduce the vibrations.
Proper framing is also crucial to the performance of a whole-house fan. In some cases, you may want to mount the fan using sponge-like material, which will reduce noise by providing a cushion between the body of the fan and the wood framing. This is a home-design option that can be utilized on an already-installed fan as well.