While a whole-house fan can help cool down your home by drawing in cold air from outside, an attic fan can reduce attic temperature by removing hot air from the attic. And both these appliances can improve the energy efficiency of your existing cooling systems.

The temperature in the attic of your home can rise very quickly, especially in summer, as it receives direct heat and sunlight. Hence, cooling it down may bring down the interior temperature of your home more effectively.

Now, both whole-house fans and attic fans can help you achieve this, especially when paired with an air conditioning system. But which one will best fit your needs? Find out in my extensive guide below!

Whole-House Fan Vs Attic Fan

1. Working Mechanism

A. Whole-House Fan

Whole-house fans use electricity to remove hot air from the interior of your home and draw in fresh, cool air from the outside via the doors and windows, ultimately sending it to the attic. This is what enables them to cool the entire home at once, making them a worthy replacement for HVAC systems. In fact, many homeowners who don’t have the budget to install an HVAC unit or central air conditioner opt for a whole-house fan instead.

Installation-wise, a whole-house fan should be installed on the center of the ceiling of the top-most floor of your home for maximum efficiency. However, both the size of your home and the CFM (cubic feet per minute) count of the fan will determine its air-regulating capacity. 

For instance, whole-house fans with the highest CFM count can facilitate air change up to 6 times every hour, thereby bringing down your home’s temperature significantly. You will see the vents on your ceiling opening and closing, as the fan draws in and expels air, respectively.

Keep in mind, though, that since the unit will effectively draw in more air at the ceiling, you should make enough space for it. This is to say, you may need up to 4 times the area of attic vents than normal. 

B. Attic Fan

You can think of attic fans as electrically-powered exhaust fans that remove hot air from the attic space. This function is triggered by changes in a thermostat placed within the attic, with the temperature usually ranging from 60 to 120 degrees Fahrenheit. Simply put, an attic fan can help cool the attic air when prompted by a thermostat.

Also called power attic ventilators or PAVs, attic fans have an intake component typically located near the fascia, under the eave, or soffit of the roof to bring in fresh air from outside. When the fan removes warm air from the attic, it simultaneously draws in fresh air from the intake.

Now, for the largest time, I was under the impression that attic fans can only be installed anywhere in the attic. However, this isn’t entirely true, as they’re generally installed on the gable or roof. And depending on this location, attic fans can be categorized as:

1. Gable Attic Fans

As the name may have suggested, gable attic fans are located on the gable of your attic, and the placement is typically vertical. When the temperature in the attic rises, these fans switch on immediately to push hot air out from the gable.

2. Roof Attic Fans

Although roof attic fans are mounted on the roof, they are installed partially inside the roof and partially out of it. These fans are usually mounted as high as possible, but it’s important to maintain a gap of at least 24 inches between the fan and the ridgeline of the roof.

2. Cooling And Ventilation

A. Whole-House Fan

Since whole-house fans cool the interior of your home by drawing in air from the outside, they are only suitable for areas where the outside temperature is less than the interior temperature. For instance, a whole-house fan can make your home cooler after sundown, when outdoor temperatures become cooler than your home’s interior. Once the cool air reaches the ceiling, it will dissipate uniformly inside your home.

Besides, the constant intake of fresh air eventually replaces the stale air inside, making for effective ventilation. 

B. Attic Fans

Unlike whole-house fans, attic fans don’t facilitate air movement within the home- instead, they simply reduce the attic temperature by driving out warm air. This, in turn, can cool down your home, as a hot attic will radiate heat through the ceiling, gradually warming up the entire space.

From what I have observed, attic fans don’t ventilate your home as efficiently as whole-house fans. However, the intake of fresh air inside the attic makes it well-ventilated, making it less susceptible to moisture and mold formation.

3. Operation

A. Whole-House Fans

Whole-House fans are operated manually, but you should open the doors and windows before switching on the fan. Moreover, you can either operate a whole-house fan using a wall switch or opt for a pull cord that hangs from the ceiling. 

B. Attic Fans

Attic fans are among the most convenient appliances to operate as they function automatically. All you need to do is program the thermostat to set an “activation temperature.” Once the temperature in the attic reaches the preset temperature, the fan will switch on automatically. You can also reprogram the thermostat according to the changing temperatures during different seasons.

Long story short, you don’t have to put in any extra effort, like opening the doors and windows.

4. Ease Of Installation

A. Whole-House Fan

Aside from a functional electrical connection in the attic, installing a whole-house fan will require cutting the ceiling (or ceiling drywall) to attach the damper box to the joists. This process generally becomes more difficult in case of whole-house fans with larger diameters, as they require the support of at least two joists. As a result, you may have to cut and shape the joists to make room for the installation.

Not only that, but the reshaped ceiling joists would also need extra support, typically in the form of two side pieces. Apart from that, the vent tube and fan should be hung from the rafter with durable hanger strips.

Overall, a whole-house fan installation can be quite tricky, time-consuming, and expensive, so make sure you hire the best professionals for the job. Going the DIY way may have disastrous consequences!

B. Attic Fan

Because attic fans don’t ventilate air per se, you don’t need to go through the trouble of extending the outflow of the attic outdoors. So, as long as there’s a functional electrical connection (in case of electric-powered attic fans) in the attic, you should be good to go. Besides, getting an attic fan installed is almost always less expensive than installing whole-house fans.

5. Sound Output

A. Whole-House Fan

Unless the ceiling of your topmost floor is too low, the sound of a whole-house fan won’t hammer your eardrums. Likewise, ceiling insulation can dampen its operational noise. Moreover, there are many whole-house fans that come with an insulated insulator, which increases the distance between the fan body and the ceiling, thereby reducing sound transfer.

B. Attic Fan

Since attic fans are mounted either on the gable or roof (depending on the model), they remain separated from the ceiling and larger, open spaces like your central hallway. Hence, attic fans become virtually noiseless, especially if there’s existing sound insulation on the ceiling.

6. Appearance

A. Whole-House Fans

Although whole-house fans are installed in the attic, they are generally more visible than attic fans, as they extend to the ceiling, too. Besides, larger whole-house fans can be as wide as your ceiling joists, with their length ranging between 36 and 40 inches, making it difficult to conceal them.

B. Attic Fans

Attic fans are considered better for compact spaces unless you’ve multiple attic fans located on the roof or gable. You can easily find attic fans that will fit your attic space, including gable fans that can be completely concealed behind the gable vent.

Pros And Cons

Now that you have a better understanding of how house fans and attic fans work for various factors, let me take you through their pros and cons to help you make the right choice.  

A. Whole-House Fans

Pros:

1. Better Whole House Air Circulation

Whether paired with air conditioning systems or operated on their own, whole-house fans can result in better air circulation by removing stale air and bringing in fresh air. 

Not only that, but a whole-house fan can also render a subtle “breeze effect,” which can be a great way to make your house cool. This cooling effect is similar to that created by a stand fan operating on low to medium speed but for the entire house.

2. Works For Drier Climates

If you live in a region that has a drier climate, you might have noticed how the outdoor air becomes cooler than the indoor air post-sundown. And a whole-house fan can be the ideal cooling method in such a case, as it will bring in the cooler outdoor air to make your home cooler.

In fact, operating the whole-house fan for just 30 minutes can keep your entire home cool for the night, depending on the square footage and the capacity of the fan.

3. Can Bring Down Energy Bills

Although whole-house fans and air conditioning systems cannot be operated at the same time, the former can help your ACs become more energy-efficient. As the temperature inside reduces with the help of a whole-house fan, it takes the pressure off your AC unit to cool the space faster.

Cons:

1. Not For Every Climate 

In case of regions with warmer climates, the outdoor temperature will likely be equal to or even more than that of your home. Besides, the outdoor air may have high levels of humidity, and both these factors will severely compromise the utility of a whole-house fan.

2. May Increase Indoor Humidity Level

Since whole-house fans pull in outside air and direct it towards the attic, the high humidity outdoors will eventually accumulate in the attic. Over time, this may result in the formation of mold and mildew, as well as affect indoor air quality. Hence, you may take adequate measures, like installing a dehumidifier, which will be an added expense and hassle.

B. Attic Fans

Pros:

1. Help Reduce Humidity In The Attic

As a homeowner, you must know that your attic is one of the most susceptible places for developing mold and mildew. Apart from triggering allergies and respiratory diseases, both mold and mildew formation can cause damage to the foundation of your home. However, the “attic-specific” air circulation of attic fans can reduce this possibility.

2. Can Protect The Roof

Attic fans can be a great way to reinforce the durability of your roof by keeping the attic cool. This can be especially beneficial for asphalt shingle roofs, which may get damaged faster if exposed to constant heat. 

3. May Prevent Ice Dampening

During winter, the warm air inside your home can reach the attic and melt the snow accumulated on the roof. This phenomenon is called ice dampening, a commonplace in regions with cold climates. When the melted snow dribbles down to reach the cold edges of the roof, it freezes back to form an ice dam, which can retain more water and eventually leak into the roof. 

However, installing an attic fan can successfully help prevent ice dampening, as it can quickly cool down the attic.

Cons:

1. Need To Be Paired With Air Conditioning Systems

Cooling your home by means of a cool attic will take much longer, which means it may be necessary to pair your attic fan with an AC, especially in warmer regions.

2. Not Very Energy-Efficient

Unless you can rely exclusively on attic fans to cool down your home during summer, you won’t see considerable energy savings on your electric bills. 

Final Words

Both whole-house fans and attic fans have specific utilities, so it’s important to consider your needs before taking a pick. 

For instance, if you want to keep your whole house cool while ensuring proper air circulation, a whole-house fan will be the right option. Similarly, if you think that reducing the attic temperature will help cool down your home faster, then you may consider installing an attic fan. 

Furthermore, I’d recommend speaking with an expert to figure out what best suits your requirements and budget. They can also help you with making the adjustments required for a safe and effective installation. 

See you another day!