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.

Steamy Temps Bring Summer Window Woes

This past week’s brutal heat and sky-high humidity had many of us hiding indoors, glued to the AC. But while we were doing our best to stay cool, our windows may have been trying to tell us something. If you’ve noticed water droplets forming on the inside of your windows—or a foggy film that just won’t quit—you’re dealing with summer window condensation. And no, it’s not just a minor annoyance. It can be a sign of bigger problems brewing in your home.

So, what’s going on here?

Condensation forms when warm, humid air hits a cooler surface. In the winter, that’s usually on the inside of your windows. But in the summer, it’s the reverse. Your air conditioner is keeping your indoor air refreshingly cool, while the air outside is heavy and hot. When those two climates meet, like when humid air seeps in and touches your chilly window glass, moisture condenses, and you get that telltale fog or water buildup.

In reality, a little condensation now and then isn’t the end of the world. But if you’re noticing it regularly, especially during extreme heat and humidity, it can point to problems with ventilation, insulation, or moisture control in your home.

In our Connecticut climate, summer humidity is no joke. Add in long showers, laundry, cooking, and even houseplants, and you’ve got a recipe for excess indoor moisture. If your home doesn’t have proper airflow or if your windows aren’t up to the job, that moisture sticks around, and your windows become the battleground where it all shows up.

And here’s the thing: if you ignore it, condensation can go from cosmetic to costly. Excess moisture creates the perfect environment for mold and mildew, which can trigger allergies, irritate lungs, and leave a lingering musty smell. Over time, moisture can also cause wood window frames to warp or rot, damage seals, and reduce your windows’ effectiveness. Even if it’s just clouding your view, you’re still losing out on natural light and visibility.

So, what can you do?

Start with airflow. Use exhaust fans in bathrooms and kitchens, and don’t be afraid to crack a window when the outdoor air is drier. A dehumidifier can also make a significant difference, especially in areas prone to moisture, such as basements.

Next, take a hard look at your windows. If they’re single-pane or older double-pane units, they might not be insulating properly. Modern double- or triple-pane windows are designed to prevent this kind of condensation by minimizing temperature swings on the glass surface.

And don’t forget the little things like sealing air leaks around windows and doors, opening blinds or drapes during the day to improve air circulation, and keeping indoor plant collections in check. Every small step helps.

Condensation might seem like a minor inconvenience, but it’s often a symptom of bigger issues in your home’s comfort and energy efficiency. Take care of it now, and your windows and your wallet will thank you later.

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.

Tackling Humidity Hazards at Home

With all of this heat, humidity, and rain, now is the perfect time to talk about what high moisture does to your home. 

Let’s start with a bit of background. Mold is made up of thousands of microscopic spores that travel through the air until they land on a surface. They love to live in places that hold water, which is why you often see mold growing on trees, roofs, and other places that stay warm and damp. Indoor mold generally develops after being carried in from the outdoors or because of a leak that hasn’t been remedied. Homes that tend to hold a lot of humidity are more susceptible to a mold infestation, something that no homeowner wants to deal with. 

Many people are sensitive to mold and mildew, especially children and the elderly. It grows and spreads incredibly quickly and cannot be contained without removing its food source, which is water. Once it settles inside a home, mold can cause illness, asthma, and a host of other respiratory issues that can affect a person’s health for life.

So how can you get rid of mold in your living space, or prevent it from making a home in yours? Here are my top tips.

1. Run a dehumidifier in your basement constantly. I have an air-tight finished basement and I still run a dehumidifier 24/7. The goal here is to keep your air humidity at or below 50%. When it’s raining or super humid, don’t be surprised if you have to dump the water collection bucket twice a day. 

2. Always use the extractor fan while showering or cooking. With so much water in the air from the weather, the last thing you want to do is add more moisture inside your home. Be sure that your fans vent outside, not in the attic. Otherwise, you’re just redirecting the moisture to another part of the house. 

3. An air conditioner is not a dehumidifier. Sure, it will remove some humidity but an air conditioner’s main function is to cool the air, rather than remove the water. If you find yourself running your A/C unit to control your humidity, you’re going to end up with an expensive energy bill and not too much to show for it.

4. Store unused clothing and linens in airtight plastic. People often put winter clothes and bedding up in the attic, which can be a breeding ground for mold if the area is not ventilated properly. Keeping the attic vented is key, good airflow can slow or even prevent mold growth.

5. Rain has been plentiful so far this month, so check your drainage. Gutters should be clean and in working order and your landscaping should slope away from the foundation so you don’t have standing water at the base of your home. Make sure your downspouts extend at least four feet out and away from the house.

In short, a house with high humidity is nothing to ignore. If you suspect that your home might be susceptible to mold, it’s worth purchasing an inexpensive humidity gauge to find out. Remember, a mold problem can be a serious health risk to your family if not dealt with properly. 

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 http://www.odonnellbros.com. Advice is for guidance only.