Investing in the right insulation is one of the most cost-effective ways to keep your home cool. In warmer climates, insulation acts as a thermal barrier to keep cool, treated air inside while preventing heat conduction that could warm your garage, roof, walls, and eventually your whole home. Learn how the right insulation keeps heat out, plus the best materials for specific applications throughout your property.

How Is Insulation Supposed to Keep My Home Cool?

Many homeowners associate insulation with cold winters, but it’s equally important in hot climates. Whether the heat is inside or outside your home, insulation serves as a thermal barrier by slowing the transfer of radiant and conductive heat through your roof and walls.

How Insulation Keeps Heat Out

Every type of insulation restricts the heat flow in its two most common forms, conduction and convection.

Conduction: Heat conduction occurs when hot air slowly increases the temperature of housing materials, such as shingles and exterior walls. As the temperature of these materials increases, they transfer heat indoors, raising indoor temperatures and making your air conditioning run more.

Choosing and installing the right insulation will keep heat out by introducing a non-conductive material to your home.

Convection: Heat convection occurs when hot air enters your home through small cracks or gaps in your walls, roof, or insulation. This direct transfer of warm air is also known as an air leak, and it increases energy consumption by forcing your AC system to work harder.

Air sealing is often the first line of defense against convection heat gain. However, removing old insulation and installing modern materials is ideal for older homes or those with a history of water damage.

What Are Good Insulators of Heat?

Modern building insulation products offer exceptional thermal performance, with each material offering unique pros and cons depending on its application, cost, and other factors.

• Cellulose insulation is an effective option for mitigating heat transfer and for air sealing.
• Fiberglass batt is widely considered an affordable, effective insulation for hot, dry climates.
• Spray foam insulation, particularly closed-cell spray foam, is a great option for warm and humid climates because it is effectively moisture-proof and offers a high R-value.

So, which is the best insulation for hot climates? It depends on your specific application.

The Best Attic and Roof Insulation for Hot Climates Is…

Spray foam insulation is ideal for attics in warm areas because it combines superior air sealing with a high R-value at lower thicknesses. Blown-in cellulose and fiberglass insulation are cost-effective alternatives, but it’s important to add a radiant barrier when using those materials.

What Is a Radiant Barrier?

Usually made from aluminum foil, radiant barriers reflect roughly 90% of solar heat and are commonly used in attics to keep indoor temperatures cooler. Installing a radiant barrier is least expensive when completed during traditional insulation installation, not afterward. It also requires an air gap to deliver optimal results.

Some examples of radiant barriers include:

• Foil-faced insulation (usually fiberglass batt)
• Foil-faced plywood
• Foil-faced OSB (oriented strand board)

Radiant Barrier vs. Insulation: Do I Need Both?

Radiant barriers of any kind are not a replacement for insulation. Standalone radiant barriers only reflect heat, but they do not slow heat transfer through conduction. Many homeowners in hot, humid climates opt for a foam-faced insulation product that combines both materials into a single cohesive system.

The Best Wall Insulation for Hot Climates Is…

Spray foam offers the best R-value and moisture-resistance, but its higher material and installation costs make it unsuitable for most insulation retrofits. However, it can be a good option for new builds or smaller projects, especially if you’re already undergoing a remodel or home improvement. Otherwise, blown-in cellulose or fiberglass is typically the more affordable option that performs well in warm weather.

Like roofs and attics, walls benefit from having both insulation and radiant barriers. Your local Koala Insulation technician may recommend adding a radiant barrier or using a foil-faced product on exterior walls that receive prolonged direct sunlight, such as east- and west-facing walls.

The Best Garage Insulation for Hot Climates Is…

Foil-faced insulation or OSB is the best garage insulation for heat protection. Since most homeowners don’t need their garage to be quite as comfortable as their primary living spaces, spray foam insulation is typically too expensive for the application. You can also use rigid foam boards for walls and ceilings, especially if your garage is unfinished.

Remember that insulating your garage won’t necessarily lower your home’s energy consumption, although it’s a smart option for attached garages. Just be sure to focus on the shared interior wall to maximize the benefits!

Installed correctly, insulation will keep heat out, lower your electricity bills by reducing air-conditioning use, and keep your family cool and comfortable all summer long!

Upgrade Your Home’s Insulation Today

Now is the time to make energy-efficient upgrades to your home, starting with professional air sealing and insulation installation. Koala Insulation provides exceptional customer service, reliable recommendations, and quality installation for homes and businesses. When temperatures rise, you’ll be glad you made the call. Find the Koala Insulation location nearest you to schedule a free quote!