Welcome to the ultimate guide on whole house fans versus attic fans — written by a licensed home inspector.
This guide will take you through the main differences between whole house fans and powered attic fans so you can decide which one is better for your home.
In this guide, you will learn that…
- Whole house fans can be a great way to cool down your house
- Why powered attic fans will protect your roof
- The differences between whole house fans vs. attic fans
- The possible safety risks of attic exhaust fans and whole house fans
- How to choose which attic fan is right for you
Let’s get started with whole house fans versus attic fans!
What Are Whole House Fans?
Whole house fans are powered fans that will ventilate an entire house, not just an attic.
Whole house fans are only primarily to cool a house so you don’t have to use your air conditioning system — saving you a lot of money.
To read our top picks for whole house fans, check out our reviews here.
Some homeowners can expect to save up to 80% on energy costs as compared to using a traditional air conditioner.
Many users also really like the “breeze effect” that a whole house fan can provide, it gives a nice and cold outdoors-like feeling to the interior.
Even though a whole house fan is primarily used to cool down your entire home (without the a/c), at the same time it will also ventilate and cool your attic.
Of course, a whole house fan would not be used during cold weather.
For certain climates, a whole house fan can eliminate the need for traditional air conditioning altogether as reported in Home Energy Magazine.
Read Also: Do Whole House Fans Really Work?
What Are Attic Fans?
The most common attic fan is mounted to the roof of a home.
It has a thermostat so when the attic’s temperature reaches a certain temperature, it will automatically turn on.
There are also gable mounted attic fans that are installed on the gable vent (the vent on the side vertical wall).
Solar powered attic fans have become more popular as well. These attic fans have an attached solar panel so the fan turns on automatically when the sun is out.
There are also turbine attic fans. These fans have a wind turbine which turns when there is enough wind. The turbine attic fan uses no electrical energy at all.
Attic fans are used to ventilate only the attic and not the whole house.
Even though having attic fans can help cool a house, especially the top level adjacent to the attic, it would be a very poor substitute for a whole house fan if you want to cool down the whole home.
Read Also: Our top picks for solar attic fans
What Are The Main Differences Between Whole House Fans & Attic Exhaust Fans?
The main difference between whole house fans and attic fans is that whole house fans cool down your whole home.
An attic fan primarily cools down just your attic.
Whole house fans are only used during during warm weather when the home’s interior is hotter than the outdoor air.
This is especially true when the sun goes down, and the outdoor temperature drops, but the home’s interior is still very warm.
Many people love whole house fans because when the sun goes down, they only have to run the whole house fan for 15-30min and the home will be cool for the rest of the night.
Whole house fans work best in drier climates and when there are large daytime to nighttime temperature differences as reported by Kansas State University.
Attic fans are also heavily used during warm weather, but they can also be used year round to ventilate the attic.
During the cold season, an attic fan’s main benefit is to remove moisture from the attic.
Excessive attic moisture during winter can lead to a phenomenon known as ice damming that can cause severe damage to a home.
Too much attic moisture can also lead to hazardous and costly mold growth.
A commonly overlooked benefit of attic fans is that they can help protect and prolong your roof shingles.
Asphalt roof shingles will prematurely age if they get excessively hot.
When the attic becomes a raging inferno during peak hot weather, the sun’s heat beams onto the shingles, and the heat transfers to the roof sheathing and wood rafters.
This heat transfers to the attic air and becomes a type of “heat trap” just like how your car heats up with the windows rolled up when parked.
Which Ventilation Fan Should I Choose?
If you want an air conditioning substitute during warm weather, then a whole house fan is the product for you.
However, if you want to protect your roof, ventilate your attic to prevent moisture, and to help cool down your upper level, then an attic fan is the right choice.
A whole house fan is actually uses the oldest air conditioning technology known to man.
It uses something known as the “stack effect” which is when hot air rises, just like hot gases going up a chimney stack.
The idea of using the outdoor air to cool the interior is an age old concept. Even Thomas Jefferson’s home at Monticello was designed to use this stack effect by installing a central cupola that exhausted out the hot air.
A whole house fan uses the same principle because it is located at the upper level of a home, and in the center hallway.