Will Insulating My Attic Keep My House Cooler?

Yes — attic insulation can significantly help keep your home cooler in the summer by preventing heat from entering your living space through the roof. Keep reading to learn how attic insulation works, its benefits for summer cooling, and why it’s an investment worth considering for your home.

Are you tired of sky-high air conditioning bills every summer? The problem may be your attic insulation. While it’s a given that insulation will keep your home warmer during the winter, it also plays a crucial role in keeping your home cool during the hot summer months.

So, how does attic insulation help in the summer? The simple answer is that it prevents heat from entering your home through your roof. Not only does this make your home more comfortable, but it also improves energy efficiency and helps save money on your utility bills.

How Attic Insulation Keeps Your Home Comfortable Year-Round

Insulation in the home, especially in the attic, helps regulate home temperature and reduces the pressure on your heating and cooling systems. In the winter, this means trapping and absorbing the heat from the home's heating system, thereby keeping the warmth from escaping into the chilly outdoors. In summer, however, insulation functions to keep the cold air in and the hot air contained to the attic, where it rises naturally due to "The Stack Effect".

What is The Stack Effect?

The Stack Effect works like this: as gases like oxygen heat up, they naturally expand and rise to the highest possible point as their density decreases. This is why, if you've ever been up to your attic or the top floor of a house on a hot summer day, you'll notice an obvious temperature difference as you head up — no matter how much you run the air conditioner. With the sun beating down on the roofing all day long, the air inside will heat up over time, making the rest of the home uncomfortable. However, if the attic space is properly insulated, that hot air won't get a chance to escape and elevate the overall temperature of your home.

In the end, attic insulation not only helps to keep you warm in the winter, but it also helps to keep the whole home cooler during the hot and sticky summer months.

How Attic Insulation Works

Attic insulation helps to absorb the heated air that is produced by your heating system during the winter, keeping the warmth inside. In the summer, it prevents hot air from spreading down into your home from the attic, where temperatures can reach extreme levels. Efficient attic insulation helps your air conditioning system run more effectively, allowing you to save on energy costs while also reducing the release of harmful gases into the atmosphere.

To fully understand how insulation works, it's helpful to know the different ways heat travels through your home: conduction, convection, and radiation. Insulation effectively slows or stops heat transfer in all three forms, keeping your home comfortable throughout the year.

• Conduction: Heat moves through solid materials, like how a down jacket traps body heat to keep you warm in cold weather. In the summer, heat from the sun warms your roof, which then transfers heat into your home. Insulation slows this process.
• Convection: Heat moves through the air. Insulation materials trap air, which helps prevent heat from circulating into your living space. A good example of convection heat is how radiators work in older homes, which function by pushing hot water through metal pipes to warm the air in the room.
• Radiation: Heat radiates from a source, like how the sun warms the Earth or fire heats a room. Insulation materials with reflective surfaces (like radiant barriers) help prevent this heat from entering your home.

Types of Attic Insulation

When it comes to how to cool an attic, insulation plays a key role. There are many different types of house insulation available, and it’s important to select the one that best suits your property’s needs and climate.

• Blown-In Cellulose Insulation: Made from recycled paper, cellulose insulation is eco-friendly and cost-effective. It has an R-value of R-3.5 to R-4 per inch and is best suited for filling gaps in hard-to-reach areas.
• Rigid Foam Insulation: This type of attic insulation offers a high thermal resistance at R-4 to R-6 per inch. It’s also moisture-resistant and durable, making it ideal for climates with extreme temperatures and humid conditions.
• Spray Foam Insulation: With an R-value of R-5 to R-6 per inch, this type of attic insulation expands to fill gaps and cracks, making it highly effective for air sealing and insulation in hard-to-reach spaces.
• Fiberglass Batt Insulation: One of the most common and affordable solutions, fiberglass insulation provides an R-value of around R-3.2 per inch. While it works well for standard attic spaces, it can leave gaps in irregular areas.
• Radiant Barriers: Made of reflective materials, radiant barriers are typically installed in the roof's attic or rafters to reflect heat away from your home. These barriers are particularly effective in hot climates where they reduce the amount of heat entering the attic, keeping your home cooler during the summer.

With so many options, choosing the right insulation for your attic can be tricky. It's always a good idea to consult a professional attic insulation contractor who can assess your home and recommend the best attic insulation tailored to your specific needs.

Benefits Of Attic Insulation In The Summer

There are numerous benefits to insulating the attic besides just helping to keep your home cooler in the summer and warmer in the winter.

Increased Energy Efficiency

By nature of their construction, our homes have tiny gaps and cracks in the building material that inadvertently allow outside air into the home, and for indoor air to escape. These cracks cause your home's cooling system to work harder to compensate, and often you're still left with hot and uncomfortable areas of the home, especially if it's an older construction and a multi-level home. Insulation fills and blocks these cracks and gaps, increasing the home's overall energy efficiency. An added benefit: along with a cooler home in the summer, you'll notice a significant decrease in your energy bills and more money to devote to summer fun!

Increased Home Value

If you've been thinking of listing your home, checking in on your attic insulation could be a good first step. A properly insulated home generally sells for more, allowing you to recoup your investment. You'll also prolong the lifespan of your roof and save on future maintenance costs!

Decreased Carbon Footprint

When you run heating and cooling systems in a home without proper insulation, they have to work twice as hard. This expels harmful chemicals into the atmosphere, increasing the risk of damage to the planet. By properly insulating your home, you decrease the amount that your home's systems have to work to regulate the temperature, thereby decreasing the amount of chemicals released.

Improved Indoor Air Quality

Insulation fills and blocks cracks and gaps in your home that lead to the outdoors, which not only keeps your house cooler in the summer, but also prevents allergens and toxins from getting inside.

Other Ways to Improve Summer Energy-Efficiency

Besides attic insulation, there are other things you can do to improve your home’s overall energy efficiency.

Install Insulation With the Proper R-Value

R-value is an insulating material’s ability to resist heat flow. The higher the R-value, the higher the insulating power of the material. According to the Department of Energy, the R-value of your insulating material should be at least R-30, with thicker layers of insulation reaching higher R-values.

Install an Attic Hatch Cover

The attic hatch is a large hole in the attic floor with a door and an attached, retractable ladder for easy access to the attic space, and it is a common feature in many homes across the world. Usually, access to the attic is through one of these, but the gaps around the attic door frame can cause air to leak through. An attic hatch cover, which can be either a zip-up cover or a removable board, helps block additional air leakage between your attic door and its frame.

Place Insulation In All the Correct Areas

Understanding how to insulate an attic is also essential because it allows you to ensure that insulation is placed in all the right locations to maximize energy efficiency. Key areas to focus on include those around ducts, the attic floor, ceiling, and knee walls. Properly insulating these areas will help adequately cover the attic space, preventing heat loss in winter and heat gain in summer.

Invest In Air Sealing to Eliminate Gaps and Air Leaks

In addition to proper insulation placement, investing in air sealing is crucial for optimal attic performance. Air sealing involves injecting foam into cracks and gaps throughout the home, blocking airflow and preventing drafts. This step ensures that your attic achieves the highest possible level of energy efficiency.

How Much Money Can Insulating an Attic Save You?

High-quality attic insulation can significantly reduce heating and cooling costs. When combined with air sealing, homeowners see an average of 15% in savings. The savings depend on several factors, including the type of insulation, the climate zone, and the insulation in the rest of your home. Whether you’re upgrading an older home or installing insulation for the first time, the long-term savings can quickly offset the initial investment.

Keep Your Home Comfortable This Summer with Attic Insulation

This summer, invest in proper attic insulation and enjoy the many benefits of energy efficiency for your home and family. Improve the air quality in your home, reduce stress on your AC units, and stay more comfortable in your home throughout the hot summer months with attic insulation.

Attic Systems is a network of highly trained and experienced attic insulation contractors that can help make your home more comfortable and energy-efficient. To get started, find your local Attic Systems contractor and claim your free, no obligation estimate!

Updated July 2025