Best Insulation for Hot Climates

If you’re a homeowner in a hot climate, you know there’s nothing more satisfying than the comfort of a cool, air conditioned house. You also know that this comes at a price—your energy bill. 

If you’re wondering how to keep your house cool, you can do so and save money on your utilities with the proper attic insulation. In this guide, we’ll discuss how attic insulation can help keep temperatures and electricity costs down, what you’ll need to know about finding the right insulation for your home, and the types of insulation for hot climates.

Let’s dive in.

How Attic Insulation Can Keep You Cool and Help You Save

By adding attic insulation, you can maximize your comfort by ensuring yourself a cool escape from the outside heat—but there are other benefits as well, including:

  • Helps your air conditioner work more effectively – Most homes in the U.S. are leaking energy. In fact, 9 out of 10 homes are under-insulated. When your home is under-insulated, your air conditioner has to work even harder to regulate your home’s temperature throughout the day. This means you end up spending more money on your electricity bills. 
  • Counteracts rising electricity costs With U.S. residential electricity prices rising nearly 40% since 2004 (and continuing to rise), proper attic insulation can help keep utilities costs low.
  • Saves big on electricity – According to the Environmental Protection Agency, you can save an average of 11% on total energy costs just by adding attic insulation to your home.
  • Supports a healthy climate – On a larger scale, adding insulation to make your home more energy efficient helps lower greenhouse gas emissions. In fact, there are many federal, state, and local utility incentives that reward homeowners for implementing this type of energy efficient home improvement. 

Attic insulation is an effective way to save money and help your home stay comfortable in hot, dry climates. However, insulating an attic is not an easy task. 

In order to experience all the benefits of attic insulation, it’s crucial that the installation be done properly. Plus, because attic insulation for hot climates differs from attic insulation for cool climates, it’s important to know the correct type of insulation to use. 

So what type of insulation is best for hot climates? 


To better understand what type of attic insulation is best for hot climates, you will help to learn about R-value.

R-value is the rating used to indicate the insulation material’s thermal resistance—in other words, the material’s ability to slow heat transfer. The best insulation for hot dry climates requires an R-value between R30 and R60, depending on your specific area. 

For example, in southern California, insulation with an R-value of R30 will provide optimum insulation for your attic without being overly costly or overly insulating. In fact, anything over R38 is not recommended in southern California. While you may gain some additional energy efficiency, the initial cost of investment for insulation over R38 may offset any savings on your energy bill. 

Type of Insulation

While the proper R-value is essential to your attic insulation’s effectiveness, it’s equally vital to use the best type of insulation material for your climate. There are several types of insulation material available, the most common being fiberglass, cellulose, spray foam, and mineral wool. 

Fiberglass Insulation

Fiberglass insulation is probably what comes to mind when you think of insulation—a fluffy, cotton candy-looking material. Far from fluffy, fiberglass is actually made of extremely delicate glass fibers composed of recycled material and sand. 

Fiberglass is the most common type of insulation used for residences because it is by far the best, particularly for hot climates. Here’s why:

  • Fire-retardant – Fiberglass insulation is fire-retardant, making it an ideal choice for homes in dry climates and areas prone to fire. 
  • Water-resistant – Fiberglass insulation is also water-resistant. In hot, humid climates, this is crucial in preventing moisture from building up in your walls. A buildup of moisture can lead to mold growth—a costly problem to fix and a serious health risk. 
  • Formaldehyde-free Since 90% of fiberglass insulation on the market today is formaldehyde-free, fiberglass insulation is by far the safest choice to use within your home.
  • Does not settle – Retaining its R-value for years

Not only does adding fiberglass insulation to your home improve your home’s energy efficiency, it also improves the value of your home. A 2016 report in Remodeler Magazine listed adding fiberglass attic insulation as one of the top home investments to make because of its 117% return on investment through the increase in home value. 

Cellulose Insulation

While cellulose insulation is the second-most common type of insulation used in residences due to its budget-friendly price, there are considerable downsides to using it. 

  • Absorbency – The most negative aspect of cellulose is that it absorbs water and moisture from the air. In a hot, humid environment, more moisture in the air means more moisture absorbed into your insulation.
  • Durability – Because cellulose is made from recycled goods like newspaper and cardboard, it can begin to degrade as soon as 15 years after installation. In comparison, fiberglass insulation can last between 20 to 30 years in most homes. While cellulose costs less than fiberglass initially, you’ll end up paying more for it in the long run. 

Spray Foam

As its name suggests, spray foam is applied by being sprayed onto desired areas. While this substance may seem simple, there are a few significant factors to consider before choosing spray foam to insulate your attic:

  • Typically for industrial buildings  – Spray foam is typically used for industrial applications. In residential homes, spray foam can interfere with plumbing and wires in the attic.
  • Difficulty in application – The spray application method is actually quite difficult. This increases the likelihood of having gaps within your insulation or getting insulation on pipes and electrical work in your attic. If you choose spray foam for your attic, be sure to consult experts!
  • Safety concerns According to the California Department of Toxic Substances Control, methylene diphenyl diisocyanate, the main ingredient used in spray foam, is known to damage lungs, cause asthma, and trigger asthma attacks. Once again, if spray foam is the right choice for your home, please talk to professionals. They’ll have the expertise and the gear needed to implement it correctly.

Radiant Barriers: Another Option in Insulation

If you’re living in a hot climate, another effective way to make your home more energy efficient, is to install radiant barriers in your attic. 

Unlike insulation, which slows the flow of heat, radiant barriers use highly reflective material (typically aluminum foil) to reduce the amount of radiant heat within your attic. 

When your roof heats up under direct sunlight, that heat transfers to your attic floor and other attic surfaces, including your insulation, ductwork, or HVAC equipment. Radiant barriers work by reflecting that heat back up toward the roof, making them ideal for hot climates. 

If you’re unsure whether radiant barriers are right for your home, considering the following questions:

  • Is your home in direct sunlight for most of the day?
  • Do you live in an area where temperatures can reach over 100 degrees Fahrenheit for weeks at a time?
  • Do you have ductwork or HVAC equipment installed in your attic? 

If you answered yes to any of these questions, radiant barriers might be the ideal option for reducing your home’s cooling costs. However, the effectiveness of radiant barriers relies largely on their proper installation, as they work best when placed perpendicular to the source of solar radiation. For this reason, it’s important to hire a professional to install your radiant barriers.

Professional Installation

Insulating your attic with the proper R-value and insulation material for a hot climate is one of the most cost effective ways to lower your power bill and keep your home cool. But just like radiant barriers, the effectiveness of your insulation is dependent on proper installation. The only way to guarantee that your attic insulation is installed properly is by hiring a professional to do the work. 

Professional insulation installers have been extensively trained to keep important factors in mind to ensure the best installation possible.

Eliminating Air Leaks

Professionals understand how to properly install insulation so that you get your money’s worth. They know how to seal air leaks and eliminate gaps between the insulation and your attic space to ensure two things:

  • Effective coverage
  • Energy efficiency

Eliminating air gaps is crucial not only in reaching the recommended R-value of your insulation, but also in preventing moisture from building up in your walls. When gaps are present, the cool moist air from your home can rise up and escape from these gaps, leading to condensation and mold growth. With professional installation, you can avoid this issue altogether.  

Under-installation, Over-installation, Proper Installation—The Goldilocks Effect 

A professional will also be able to accurately determine the amount of insulation you need. Overly insulating your attic can be just as detrimental to your energy efficiency as under insulating. Too much insulation in your attic can negatively affect your attic’s ventilation and air circulation. Without proper ventilation and circulation, your attic is at an increased risk of moisture buildup and mold growth. 


Another reason to hire a professional is to keep you safe. Attics can be dangerous. Tight attic spaces are culprits for injuries and falls. Attics can also be home to contaminants such as rodent infestations and mold. If you do have rodents or mold, removing any old insulation can release dried contaminants into the air, endangering your health. 

Professionals have the necessary equipment to keep themselves safe from injury. They also have tools, such as specialized vacuums and specialized bags, to remove any old insulation without spreading contaminants. A professional will also know how to safely dispose of any old insulation, as it cannot simply be thrown away. 

Trust Attic Construction for Your Attic Insulation

If you’re living in a hot climate, your attic insulation has a huge effect on the energy efficiency and comfort of your home. For even more energy efficiency, radiant barriers can be added to your attic to drive heat away from your insulation. By taking these steps to make your home more energy efficient, you will significantly reduce the amount of work your air conditioner needs to do, saving you money on your energy bills.

To guarantee that you’re getting the most out of your attic insulation, it’s essential to hire a professional to do the installation. Our team of professionals have the expertise and the tools to install your attic insulation properly, quickly, and safely. Our goal is to save you money, time, and hassle. 

With our help, you won’t have to wait long to start enjoying lower energy bills and relaxing in the comfort of your cool, air conditioned home. Reach out to an expert today.

Attic Construction offers San Diego, Orange County & Phoenix insulation installation; contact us for a free estimate.


  1. Energy Star. Why Seal and Insulate?
  2. Insulation Institute. Home Insulation: The Value of Insulating Your Home.
  3. Energy Star. Recommended Home Insulation R-Values.
  4. Department of Energy. Insulation.
  5. REenergizeCO. When to Replace Your Home Insulation.,or%20a%20home%20energy%20audit.
  6. Department of Energy. Radiant Barriers.


Leave a Comment

Your email address will not be published. Required fields are marked *