Ventilation 101: How to Keep Your Attic from Turning Into a Sauna

Most homeowners don’t think about their attic unless something goes wrong. But during the hot, humid summer months in Connecticut, poor attic ventilation can cause a lot of problems. Some you’ll feel in your cooling bills, and others you might not notice until it’s too late.

Here’s why proper attic ventilation matters and how to know if your home needs an upgrade.

Why Your Attic Needs to Breathe

Your attic should be the same temperature as the air outside. That might sound surprising, but it’s true. In the summer, without proper airflow, your attic can easily reach 130°F or higher. That heat doesn’t just stay in the attic - it radiates down into your living space, forcing your air conditioner to work harder and driving up energy costs.

Hot, stagnant air can also cause your roofing materials to age prematurely. Shingles can blister, underlayment can warp, and moisture can build up, leading to mold, mildew, and even wood rot.

Good ventilation helps control both heat and moisture, keeping your attic and roof in better shape, and your home more energy-efficient.

The Basics of a Ventilation System

A well-ventilated attic has two things: intake and exhaust. These work together to create a continuous flow of air.

• Intake vents (usually located in the soffits under your roof overhang) pull fresh air into the attic.

• Exhaust vents (at the roof ridge, gables, or high up on the roof slope) allow hot, humid air to escape.

This system relies on the natural movement of air—cool air in, hot air out.

Common Ventilation Types

• Ridge vents: Run along the peak of your roof and are often paired with soffit vents. They’re effective and barely noticeable from the street.
  Soffit vents: Located under your eaves, they bring in cool outside air.

• Gable vents: Installed on the walls of the attic, often used in older homes.

• Powered attic fans: Use electricity to actively pull hot air out. These can be helpful but aren’t always necessary if passive ventilation is working properly.

Signs of Poor Attic Ventilation

• Your upstairs rooms are always hotter than the rest of the house.

• You notice high energy bills in the summer.

• Your roof shingles are curling or deteriorating faster than expected.

• There’s mold or a musty smell in the attic.

• You see frost or condensation in the attic during winter (yes, ventilation matters year-round).

Here in Connecticut, we deal with humid summers and cold winters, which means both heat and moisture are issues. That makes proper attic ventilation even more important. It’s not just about comfort, it’s about protecting your roof, improving air quality, and saving on long-term energy costs.

If you’re unsure whether your attic is properly ventilated, a quick inspection by a professional can help. It’s one of those home systems that’s easy to overlook, until it’s not.

Bob O’Donnell is the owner of O’Donnell Bros. Inc., a Bristol-based home improvement company established in 1975. Got a home issue you’d like Bob to tackle? Email info@odonnellbros.com with the subject line “Ask the Pro.” To contact Bob for your remodeling needs, call O’Donnell Bros. Inc. at (860) 589-5155 or visit http://www.odonnellbros.com. Advice is for guidance only.

Let Your House Breathe and Say Goodbye to Dangerous Moisture

You hear me talk a lot about the importance of insulation in the home, especially at this time of year and with our recent, frigid temperatures. But even if you’re the one in every four houses I visit that actually does have the right amount of insulation, chances are that your ventilation is inadequate, which can be harming both your home and your personal health in more ways than you think.

In the winter, we crank up the thermostat, sending more heat and moisture into the living quarters of our homes. We all know that heat rises to the top, which means a lot of what we’re pumping into the house will quickly find its way through the ceiling and into the attic. Now, think about when you’re in a car and the windows fog up. What do you do? Usually, you’ll increase the airflow either by using the vents or just cracking a window. A house works much the same way, except that if you don’t have airflow in the attic, the heat and moisture just gets stuck there. If the attic is very warm, that moisture will develop into mold and mildew which can fester in your insulation and rot the wood. If the attic is cold enough, the moisture will freeze into little domes or even icicles until the temperatures rise enough for the water to thaw and then be absorbed into all the places it shouldn’t be going. Neither is a good scenario.

So what’s the best way to protect your home? Start by investing in a hygrometer which measures water vapor in the air. A comfortable humidity reading is 30-60%, but 45-55% is an ideal level to maintain. If you’re seeing higher than 60% humidity in any area of your home, you’re going to be susceptible to mold, mildew and bacteria growth.

Remember, attic ventilation allows your home to “breathe” so you want to balance your intake and exhaust to ensure that what is coming in is going out equally. The best ventilation system will include soffit vents which are installed underneath the overhang of the roof to take in the air and ridge vents which are installed at the top of the roof for the hot air to escape. For this method to work efficiently, all louvered vents must be sealed off and you have to ensure that your insulation isn’t blocking the airflow. Believe it or not, most roof manufacturers will void the warranty if a proper ventilation system is not installed. Luckily, new roofing technology enables contractors to add intake ventilation directly into the roof as opposed to using soffit vents so if you’re in the market for a new roof, be sure to ask for that option.

It’s important to note that homes have different characteristics and what works well for one may not work well for another. With the right balance of air, homeowners can optimize their roof and maintain the overall health of their home and their families, but it’s always a good idea to get advice from a professional before taking on a big remodeling project. Stay warm friends.

Bob O'Donnell is the owner of O'Donnell Bros, Inc., a Bristol-based home improvement company established in 1975. Email your questions for Bob to info@odonnellbros.com with the subject line “Ask the Pro”. All questions may be considered for publication. To contact Bob for your remodeling needs, call O'Donnell Bros, Inc. at (860) 589-5155 or visit www.odonnellbros.com. Advice is for guidance only.

Let Your Home Breathe with Proper Attic Ventilation

Last week we talked about how poor ventilation can cause frost and icicles inside the attic and dangerous ice dams outside at the base of the roof. These warning signs should set off alarm bells for homeowners as they can lead to major leaks and expensive damage to shingles, walls, and insulation. So let’s take a look at how to mitigate any potential problems with a quick crash course on attic ventilation.

An attic that’s well ventilated will reduce heat build-up in the summer and allow moist, warm air to escape the house in the winter. A house that can “breathe” properly is more energy efficient, keeps the home dry, and reduces the potential for ice build-up in the winter.

Have a look at your roof. Do you see any vents under the eaves, at the top of the gable or along the ridge? Some vents can be tough to spot, so if you’re unsure, think back to our recent winter storms. Did the cold temperatures result in a build up of thick ice near your gutters? If so, this is a telltale sign that your home isn’t properly ventilated. You can also check by grabbing a flashlight and heading up into the attic. If you see dampness, frost, or icicles, it means you have a ventilation problem. In the summer, just simply touching the ceiling can tell you if your vents aren’t adequate. If the ceiling feels hot, your attic is effectively acting like a solar panel, increasing your cooling bills by trapping hot air that can’t escape.

Proper ventilation works as a system with different vents controlling air intake and exhaust. As heat escapes the main living area of the house, a correct system will allow that air to flow through the attic instead of getting trapped inside it. It works like this. Escaping air from the main living space of the home will flow through a soffit vent at the base of the roof near the gutters and along the underside of the eave. As this air enters the attic, it rises up and will then look to exit, which will often be through a gable vent or a ridge vent at the very top of the roof. If the air is flowing properly, the attic will stay cool and dry and you won’t have to worry about those dreaded ice dams.

So how do you know how many vents you need for your home? Ventilation is determined by area, so start by figuring out the square footage of your attic. For example, a 30-foot x 50-foot attic would equal 1,500 square feet. Professional contractors estimate about one square foot of vent opening for every 150 square feet of attic area as per Connecticut building codes, so in this case, you’d be looking at 10 square feet of total vent area. Each vent will come with a net free vent area (NFTA) measurement to help you calculate your vent size, and the total area should be split evenly between intake and exhaust vents. Remember that vents need to be free and clear in order to work properly, so if you feel like you have enough vents but are still having issues with airflow, make sure to check that they aren’t being blocked by insulation or accidently covered over.

Have a question about ventilation, insulation or roofing? Feel free to shoot me a message on Facebook at www.facebook.com/odonnellbros.

Bob O’Donnell is the owner of O’Donnell Bros. Inc., a Bristol-based home improvement company established in 1975. Email your questions for Bob to info@odonnellbros.com with the subject line “Ask the Pro.” All questions may be considered for publication. To contact Bob for your remodeling needs, call O’Donnell Bros. Inc. at (860) 589-5155 or visit www.odonnellbros.com. Advice is for guidance only.