What Are The Pros And Cons Of Attic Ventilation Fans?

Patricia Oelze
by Patricia Oelze

If you already have or previously had an attic ventilation fan, you know how well it can cool off your house without running the air conditioner. They are also great at getting rid of toxic gases or smoke, however, there are some downsides too. So, what exactly are the pros and cons of attic ventilation fans?

Attic ventilation fans protect your attic from mold and mildew, help cool your home, and can make your roof last longer. They also will prevent ice damming and can pull toxic fumes out of your house. But attic fans can lead to a leaky roof and loss of cool air if improperly installed, and the constant humming noise can be annoying for some people.

Many of the older homes have attic fans because air conditioning really has not been around that long. Back in the old days, you could either put a window fan in your window or turn on the attic ventilation fan to cool off your house. But nowadays we have air conditioners in all shapes and sizes.

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What Is An Attic Ventilation Fan?

Almost all homes have roof vents in them. At least, they are supposed to. If not, you may be thinking about installing an attic ventilation fan. An attic ventilation fan works by sucking the hot air from the attic.

However, the typical attic ventilation fan does not pull in cool air from the outside. It only cools off the attic and ventilates the house. But in cooling off the attic, it also cools off the rooms below by about 10 degrees. There are different types of attic ventilation fans such as:

  • Solar attic fans that use no electricity
  • Electric attic fans set on a thermostat
  • Electric attic fans that work with a light switch
  • Whole house attic fans that pull in air from outside through the home’s windows.

To make the most of your attic ventilation fan, install good insulation in your attic. Also, air seal all of the cracks and gaps in the space to avoid cold air escaping. Additional ways to cool your home are ceiling fans, LED lights, programmable thermostats, and energy-efficient windows and doors.

How Do Attic Ventilation Fans Work?

Attic fans typically push hot air out of your attic in the summer months. When it gets hot outside, your attic can far exceed the outside temperatures, getting as hot as 160 degrees. When this happens, it can make the rest of your house feel hot no matter what your AC is set on.

In fact, with an attic this hot, your AC likely struggles and works overtime to cool your house. If you’re not sure just how much your attic’s temperature is affecting your house, pop up there and take a temperature reading.

Or, alternatively, you can hire an attic inspection to get an even more detailed picture of how hot your attic gets in the summer. In a nutshell, the hotter your attic, the hotter your house.

But, when you have an attic ventilation fan, it expels the hot air in the attic, bringing down the temperature to one that is more equal to the outside. Then, your AC can cool your house without battling the extra hot air coming down from the attic.

Conversely, the attic fan can keep air circulating in the winter, preventing moisture from developing when warm and cold air meets under your roof.

You Don’t Use An Attic Fan To Cool Your House

Contrary to popular beliefs, attic fans don’t cool your home. You can’t simply run your attic fan, turn off your AC, and enjoy a comfortable temperature in the heat of summer.

The attic fan’s job is to better regulate the temperature in your attic, cooling the attic down, so your AC doesn’t have to work as hard inside your home. With that being said, an attic fan could help extend the lifespan of your AC unit.

The Pros And Cons Of Attic Ventilation Fans: Advantages

If you are considering installing an attic ventilation fan in your home, you need to consider the pros and cons of attic ventilation fans. There are plenty of advantages to doing so.

Whether you get a solar or electric attic ventilation fan, it can certainly help with your utility bills in the summertime. But let’s look at some of the other benefits.

1. Pro: They Help Your Roof Last Longer

The high temperatures during summer will eventually cook your roof, especially if you have an asphalt roof. Because shingles are made from oil, they can warp and age if they get too hot. And what else can they do when they are up on the roof soaking up the sun all day?

The average shingled roof lasts about 15 to 20 years. But with too much heat, they can start fading and curling in less than seven. The asphalt is basically melting and being washed away with the rain. But with your attic fan pushing that heat out, your shingles, and your roof, will last considerably longer.

2. Pro: They Protect Your Attic from Mold and Mildew

Having a poorly ventilated attic can cause mold and mildew growth no matter whether it is cool or hot outside. When it is hot and you have your air conditioner running, the cool air from your main floor and the hot air from the attic meet, causing condensation and moisture in the attic.

And since most attics are dark, moist spaces filled with wood, mold and mildew are common without plenty of ventilation. Yes, you paid good money to get insulation but if the insulation is keeping in the moisture, the result can be deadly. An attic ventilation fan can usually keep the mold and mildew from growing any time of the year.

3. Pro: They Help to Cool Your Home

Even with just a standard attic ventilation fan, it can cool your house by at least 10 degrees. That is because the heat from your attic can cause the walls and ceilings in the rest of your home to get hotter through the wood framing and sheathing, increasing the temperatures of those rooms as well.

The heat will become trapped in your home because it has nowhere else to go. Similar to a car in hot weather, the temperatures can become dangerously high in your attic because it absorbs heat from the sun all day. Some attics can reach temperatures up to 150 degrees Fahrenheit.

4. Pro: They Will Prevent or Eliminate Ice Damming

For those who live in a cooler climate where you get snow and ice, you probably already know what ice damming is. If not, ice damming occurs when hot air from the attic warms up the snow on the roof, causing it to melt.

But when it starts to move to the edge of the roof, it starts to freeze again. Pretty soon, you have a giant dam of ice around the edges of your roof. These will either melt and fall off, which can be dangerous, or they can cause the wood to rot and leak. An attic ventilation fan can prevent this by keeping the roof from getting too hot.

5. Pro: They Can Pull Toxic Fumes Out of the House

Since the house is being ventilated through the roof, any kind of toxic fumes that build up in your home will get sucked right out the roof if you have an attic ventilation fan. Even if you do not use any hazardous chemicals, things can build up from various products in your home.

According to the Environmental Protection Agency (EPA), there are more than 400 toxic compounds found in the average home from various sources. In fact, carpeting alone can have over 200 toxins in it. Some of the toxins you may have in your home include:

  • Carbon monoxide can be found in any gas appliance like your furnace, vehicles (in the garage), stove, and fireplaces. Symptoms include nausea, vomiting, dizziness, headaches, and death.
  • Formaldehyde can come from cigarette smoke, new cabinetry, new fabrics like curtains, floor, and furniture as well as household items like pesticides, glues, and paint. Symptoms include breathing problems like asthma attacks or irritation of the skin, throat, nose, and eyes.
  • Radon is a gas that naturally forms in the ground and can be absorbed through cracks and gaps in your home. You typically will not have any symptoms until the radon has damaged your health or caused lung cancer.

The Pros And Cons Of Attic Ventilation Fans: Disadvantages

There are always going to be cons in every choice so we will explore the most common cons of having an attic ventilation fan.

1: Con: They Don’t Do Much In A Warm Climate, Unless…

If you happen to live in a warm climate like Southern California, Florida, or Texas, having an attic ventilation fan is only good if you do not get the whole-house fan type. If you have hot air being pulled into your home, it will just make things worse. Central air conditioning is the best option for those in the southern part of the country.

2. Con: Too Much Noise

Some people claim that the humming from the fan is too loud or irritating. However, this is usually due to some kind of faulty installation or damage. A properly installed and maintained attic ventilation fan typically runs fairly quiet, so you should barely hear it.

3. Con: Improper Installation Can Lead To Problems

It is best to have a professional do it unless you know what you are doing. That is because if you do not seal the attic ventilation fan properly, the fan can pull your cool air out through the attic. You do not want your air-conditioned air going out the roof.

Also, whenever something is installed on your roof, whether you do it or you hire someone, there is always the chance of a leak. This issue is increased if your home does not have properly installed flashing. It can also be a problem if the roof penetrations are not maintained properly.

Even a typical rainstorm can cause a leak if your attic fan is not installed right, and this is increased during high winds and major storms. You can prevent this issue by using a gable attic vent fan instead. That is because it is installed in the gable wall rather than your roof.

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Do You Run An Attic Ventilation Fan All The Time?

Regardless of the pros and cons of attic ventilation fans, you won’t hurt anything by running an attic fan constantly. In fact, it will help keep the attic temperature close to the outside temperature. Additionally, if you live in a very humid climate, running the fan all the time can provide extra protection against mold and mildew.

However, if your fan is electrical, running it continuously will crank up your utility costs. If you want to run your attic ventilation fan all the time, then you might want to consider a solar fan. Of course, it will only provide the airflow as long as the sun is shining., but it won’t raise your electric costs.

Related Questions

Should I get a whole house fan?

If you do not live in a hot climate, a whole house fan is an excellent option. It works similarly to an attic ventilation fan except it also pulls cool air into your home. You should run it early in the morning or in the evening after the temperature gets cooler.When you turn on the fan and open the windows downstairs or on the main floor, the fan will suck the heat in through the windows, bringing cool and fresh air into your house. This is best for a dry climate where it gets cooler at night so you can cool off your home.The whole house fan also helps with ventilation since it brings in the air from outside and pushes out your inside air. But it will also bring in pollen and other allergens so if you are allergic, you may want to reconsider.And the whole house fan is definitely the noisiest type of attic fan to have. It costs about $1,250 to $1,830 to install a whole-house fan.

Is a solar fan the best option for me?

A solar attic ventilation fan can lower your utility bills by a lot if you have enough sunlight to power your fan. Solar-powered fans are also safer to use than electric. However, many experts claim that they do not run at the best time of day to make them effective since they only work when the sun is shining.Solar fans are more expensive than electric models, but once installed, you don’t pay to run them. If you have a solar fan in your attic, it can help relieve some pressure from your AC without extra costs.

How much do attic ventilation fans cost?

Solar attic ventilation fans can be expensive. But the traditional electric models are much cheaper. The extra cost upfront will likely save you enough in utility bills that it will pay for itself the first year.The average cost for an attic fan and installation on a national level is roughly $450, with a range of $225 to $850. The minimum cost would be closer to $75, but you could pay as much as $1,500 for solar models. The lifespan of an attic ventilation fan is about 15 years if properly maintained.

Patricia Oelze
Patricia Oelze

I am a DIYer who loves writing about anything home-related. When I am not writing, you can find me studying for my PhD in Psychology, photographing nature, and swimming at the lake with my grandkids.

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