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Why Is Proper Attic Ventilation in the Winter Important?

January 3rd, 2023 | 7 min. read

Why Is Proper Attic Ventilation in the Winter Important?

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Your attic’s ventilation system is a crucial component of your home. But most people only think about it during the summer when their upstairs is hot. 

This is understandable because it’s more noticeable and uncomfortable when it’s hot. However, proper attic ventilation in the winter is just as important. 

For over 30 years, the team at Bill Ragan Roofing has educated homeowners on the importance of their attic’s ventilation system to their home and roof. Because of this, I’ll break down why it’s crucial in the winter.

This article covers the following:

  • What is attic ventilation?
  • Why is attic ventilation important in the winter?
  • 3 more reasons why attic ventilation is important no matter the season

What is attic ventilation? 

Your attic’s ventilation system allows your home and roof to breathe. Proper attic ventilation is crucial to your home and roof investment. 

The system works by pulling fresh air from the outside and then pushing the trapped air in the attic out through your roof vents. There are two types of attic ventilation systems; each does the job well but in different ways. 

box vent on roof(Passive box roof vent)

The first one is passive ventilation, which moves the air in an attic around by natural sources, like the wind. The second is active ventilation, which actively pulls air in from the outside and then pushes the trapped air out from the inside. 

turbine vent on roof(Active turbine roof vent)

As I said, both attic ventilation systems do the job. One isn’t better, but you will have problems if your attic isn’t ventilated properly. 

Why is proper attic ventilation in the winter important?

Based on the last section, it’s obvious that proper attic ventilation is important. But while it’s important year-round, it’s particularly important during winter months. 

In the winter, we run the heat to keep our house warm. When this warm air rises into the attic and meets the cold air, it creates moisture.

Without proper attic ventilation or attic insulation, this moisture causes condensation to form in your roof’s decking. This rots the wooden boards and can lead to structural damage over time. 

rotten roof decking(Roof decking with rot)

It’s also the perfect environment for mold and mildew to grow. But with proper attic ventilation, the excess moisture can escape while pulling in fresh air from the outside. 

This constant flow helps prevent dampness caused by the warm air getting trapped in your attic. This not only contributes to improved air quality, but also a healthy living environment for you and your family.   

Proper attic ventilation also can also help prevent ice dams on roofs after heavy snowfall or ice storms. Ice damming occurs when snow or ice freezes at the gutter line (eaves), creating a literal dam of ice. 

ice damming on gutters(Ice damming forming at gutter line)

When the snow above the dam thaws, the water can’t drain down to your gutters. This water backs up on a surface that isn’t meant to handle sitting water. 

Once this water backs up, it eventually drips into your home until it’s warm enough outside for the ice dam to completely thaw out. Proper attic ventilation helps keep your attic at a consistent temperature, which reduces the chance of ice dams forming. 

3 more reasons proper attic ventilation is important

Now you know why proper attic ventilation is important in the winter. However, there are more reasons your attic’s ventilation system is crucial to both your home and roof. 

Let’s break down 3 more reasons proper attic ventilation is important. 

1. Proper attic ventilation keeps your home’s energy bills lower

A concern homeowners have about attic ventilation in the winter is that it will make their house cold when the warm air escapes and the cool air comes in. They think this means wasted energy and high heating bills.

However, proper attic ventilation does the opposite for both the winter and summer. In fact, improper attic ventilation means your AC unit and heating unit must work harder to keep your home at the desired temperature. 

For example, if the temperature outside is 90°F, your attic can get as hot as 170˚F. Because the attic isn’t ventilated properly, the trapped heat causes your attic floor to get up to as high as 140˚F. 

This means any room below this poorly ventilated attic won’t be cool enough to sit in until the sun goes down. Not only is the room too hot to sit in, but your AC has to run harder to try to cool it down.

So, whether it’s hot or cold outside, improper ventilation equals higher energy bills that will continue until the attic is properly ventilated. 

2. Proper attic ventilation helps maximize your roof’s lifespan

Your roof’s lifespan is how many years the roofing materials will last. There are a lot of different factors that impact how long your roof will actually last. 

One of the most important factors is your attic’s ventilation. Without proper attic ventilation, the trapped hot and cold air shortens your roof’s lifespan. 

This trapped air can cause extensive damage to your roof and lead to a full roof replacement well before you need one. Improper installation in the summer causes heat to build up in your attic and literally burns your roof up. 

The adhesives in the decking will deteriorate, and your roof’s shingles will crack or curl. Remember, condensation forms when heat and moisture from the home’s interior travel into the cold attic during the winter. 

roof decking collapsing in on roof

The trapped condensation causes the roof’s decking to swell and become wavy. When this happens to the decking, it loses the ability to hold the nails, weakens its load-bearing capacity, and mold/mildew forms. 

No matter if it’s cold or hot air, your roof’s lifespan won’t be maximized if the trapped air isn’t moved around by proper attic ventilation. 

3. Improper attic ventilation will void warranties on your roofing materials

You have roof warranties to protect your investment if there’s ever a problem. You get two warranties after a roof replacement: one from the manufacturer on your roofing materials and one on your roofing contractor’s workmanship

The warranty from the manufacturer protects your roofing materials for their specified lifespan. You’ll rely on this warranty if you have a problem caused by your roofing materials failing prematurely. 

But if they find your attic isn’t properly ventilated, the warranties will be voided on your roofing materials. This means the manufacturer is off the hook, and you’ll have to spend your own money to take care of the problem.  

Do you think your attic is improperly ventilated?

Now you know what attic ventilation is, why it’s important in the winter, and three more reasons why attic ventilation is important in general. Sadly, improper attic ventilation is all too common. 

But luckily, it can be solved by hiring a great roofing contractor. So, if you think you have improper attic ventilation, all it takes is a phone call and an inspection. 

Unfortunately, finding a trustworthy roofing contractor is harder than you expect. The last thing you want is to call a roofer about attic ventilation just for them to try to sell you a roof. 

That’s why I want to give you the tips every homeowner needs to find a reputable roofer in your area. 

Since 1990, the team at Bill Ragan Roofing has helped thousands of homeowners in Nashville and surrounding Middle Tennessee areas with their attic ventilation and other roofing needs. We take pride in everything we do and are proud to back our work up with a lifetime craftsmanship guarantee. 

If you’re local to Nashville, don’t hesitate to Contact Us for any of your roofing needs. 

Here are 7 Tips to Find a Great Roofing Contractor to help you with your attic ventilation problems.

roofing contractor questions checklist


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