Both attic fans and ridge vents are popular attic ventilation methods. But which one is the better choice for you?
Here is a quick comparison between attic fans and ridge vents;
|Attic Fan||Ridge Vent|
|An electric fan that is used to forcibly exhaust air from the attic||Exhaust ports that run along the ridge of a roof|
|An active ventilation method||A passive ventilation method|
|Can cause a negative pressure in the attic||No chances of negative pressure in the attic|
|Has moving parts||No moving parts|
|Has running costs||No costs to run|
|Lower installation costs||Higher installation costs|
|Effective with all types of roofs||Not effective if the roof doesn’t have a continuous run. Eg: a hip roof|
|Can be noisy||No noise problems|
Differences between attic fans and ridge vents
1. They work differently
Ridge vents are those exhaust ports that run along the ridge of your roof. They can be only spotted by a trained eye. They are tiny in size, but they provide ample space for hot air to exhaust from the attic.
Ridge vents work only with proper attic intake vents. For these soffit vents are installed which draw cool air from the outside. Since hot air rises and it exhausts through the ridge vents, the negative pressure thus created in the attic pulls in the cold air from the outside through the soffit vents. This is the most popular passive ventilation method for the attic.
Attic fans are used to forcibly exhaust air from the attic. They are useful when there isn’t proper attic ventilation. These fans run using either electricity or solar power.
They are available in many sizes and with many features, and they are usually installed either on the roof or the gable of the attic.
Source of power
Attic fans work on electricity or solar energy while ridge vents work by natural convection. Those attic fans that work on solar energy won’t run during the night but ridge vents work whether it is night or day.
Since attic fans work by consuming energy and since they forcibly exhaust air from the attic spaces, they are called active ventilators. Since ridge vents don’t draw energy from any sources and since they work on natural forces, they are called passive ventilators.
As attic fans forcibly exhaust air, they can create negative pressure inside those attics which don’t have enough intake vents. This negative pressure can cause damages to the roofing, back-drafting of gases, and even fire hazards. Ridge vents, on the contrary, don’t cause any such hazards.
There are two types of costs associated with anything; installation costs and running costs.
Attic fans cost lesser to install when compared to ridge vents. However, since ridge vents do not consume electricity as attic fans do, they don’t add to your monthly utility bills.
Attic fans, even though maintenance-free, has a shorter lifetime compared to ridge vents. In addition, attic fans are more likely to get damaged since they have moving parts.
Ridge vents are not noisy as they don’t have any moving parts. If the wind moves too fast you may hear a whistle but I am pretty sure you won’t hear that from your couch.
Attic fans on the other hand can be terribly noisy, especially if you are using an old, cheap unit. There are whisper-quiet attic fans however they can never be as silent as a ridge vent.
Peace of mind
Ridge vents do not need supervision to run and they do not consume any energy. They are also maintenance-free. So basically if you are using vents you won’t even know they are there.
Attic fans on the other hand require control, and some intervention even though minimal. They also cause noise in the attic. So during the day, you will be thinking of your attic fan at least once.
Attic fans are cut out for any type of roof. There are many models you can choose from, and there are units specifically made for mounting on a roof or on a gable.
Ridge vents on the contrary require a continuous run of ridge area. These vents are not very effective on a hip roof or a flat roof.
Do I need attic fans or ridge vents?
If proper ridge ventilation is possible for your roof then that is recommended over attic fans. Attic fans consume energy, and they have some downsides. If you can achieve proper attic ventilation passively by just using the vents in the attic, that is always better.
However, in many cases, achieving enough ventilation to cool down an attic during summer days is not possible due to many reasons. The main reason is improper ventilation. Even though proper vents were provided initially when the house was built, these vents could be blocked overtime by insulations or other things that obstruct the free flow of air through them. Also storing a lot of items in the attic also can block the natural flow of air.
Gable vents are also not effective if there are no wind movements parallel to the roof during the day. In these cases, it is necessary to install an attic fan to cool down the attic area.
That being said, whether you need an attic fan or ridge vents can only be considered case by case, there is no one definite answer for this question.
Installing attic fans along with ridge vents: A good idea?
It is a bad idea to use an attic fan along with ridge vents. Ridge vents act as exhaust ports for hot air. However, if you install a powered attic exhaust fan near the ridge vents, the fan will disrupt the natural flow of air and draw outside air through these vents. So instead of circulating air through the attic, the fan will simply suck air in through the ridge vents and exhaust it back to the atmosphere without cooling the attic. This is counterproductive as it will reduce even the existing airflow in the attic.
Sucking air in through the ridge vents can also bring in the water when it is raining. This can damage your attic as well as cause the growth of molds.
Can I use a solar attic fan along with ridge vents?
You can use a solar attic fan along with a ridge vent as long as the former is installed on the gable and not the roof. Solar attic fans are less powerful compared to electric fans so they are not powerful enough to draw air through the ridge vents when installed on the gable. However, this should be considered only if proper attic ventilation cannot be achieved even after improving ridge ventilation.