Why Should I Install a Radiant Barrier in My Attic?

Summers in any state can get very hot. But summers here in Charlotte, NC can get extremely hot and humid. Did you know that an attic during a summer in the South can exceed temperatures of 160 degrees Fahrenheit? Talk about hot! (Keep in mind, steak only needs to be 145 degrees to be safe to eat!) Attic insulation is an important factor in reducing the thermal heat transfer in space and maximizing the efficiency of your home. While there are many different types of insulation that you could have installed (foam board, insulation blowing, amongst others), one of the less well-known options is a radiant barrier. A radiant barrier does not require a certain r-value or density. Rather, it is a reflective, shiny material that encourages heat away from or into your home. It is an extremely effective and energy-efficient material. Together with air sealing and perhaps even an attic dehumidifier, your home will be set to withstand any type of heat that it endures in the hot North Carolina summer. 

What is a Radiant Barrier? 

Let’s first discuss the basics. A radiant barrier is a reflective material that is installed in between the wall joists of your attic. It blocks the radiating UV heat that seeks to enter your home and heat the attic space. The radiant barrier reflects the heat back to its original source. It prevents the heat from being energized by UV rays or even its own heat.  Radiant heat is created without making contact with anything or the body. An article that is heated by radiant heat will be able to emit its own heat. 

Here’s an easy example. On a hot summer day in Charlotte, NC you park your car in an unshaded parking spot. What is the result of your car sitting in direct 100-degree sunlight? Your car begins to heat like an oven, reaching temperatures greatly exceeding the outdoor 100-degree temperature. Why? The items inside your car, as well as your car, begin to radiate heat. The sun reflects the windshield and begins to heat it. The dashboard experiences the same. This is because the heat energy stored in the vehicle, dashboard, and windshield begins to generate the stored heat back into the car. 

But what if you parked this same car in the same conditions in the shade? Your car would not exceed an internal temperature of 100 degrees. How come? The tree is not the reason. Rather, the tree is a barrier against the radiant heat that would cause every item in your car (and your car itself) to heat and rise. 

Radiant barriers act just like trees. Because the sun or hot air is no longer directly hitting the walls of the attic, it no longer is hotter than the ambient temperature. It ensures that the space is not reflecting against and having the stored heat energy exit into your attic and thus the rest of your home.

Benefits of a Radiant Barrier 

  • Lowered Energy Costs 

Radiant barriers are an extremely efficient type of attic insulation. Their ability to reflect radiant heat is an essential and unique feature of radiant barriers. Oak Ridge National Laboratory provided a report on its capabilities and found that it could reduce heat in ceilings by up to 42%.  This ensures that your HVAC is not overworked and is efficiently raising and lowering the temperature of your home. Radiant barriers have also been proven to reduce cooling costs by 5-10% in homes such as in Charlotte, NC where the climate is quite warm. 

  • Protects Roof Shingles

One of the main concerns clients have when we offer radiant barriers is the potential damage to their roof shingles. Radiant barriers serve to reflect radiant heat away from the attic. However, where does this radiant heat go? Radiant barriers are installed in between the wall joists of the attic, on the other side of the roof. However, this redirected heat does not affect the roof shingles in any dramatic fashion. In fact, it has been found that roof shingles only increase between 2-7 degrees with this additional barrier installed. This poses no threat to the shingles. 

  • Excellent Addition and Supplement

Radiant barriers function best when installed in addition to regular attic insulation, Whether your home has foam board insulation or is installed via insulation blowing, radiant barriers are an excellent supplement for greater efficiency. Radiant barriers should not be seen as a replacement for standard attic insulation, but rather a supplement. This dual insulation will protect and insulate your home from all three types of heat transfer: radiation, convection, and conduction.  

  • Greater Energy Efficiency

Your home is the greatest investment you will make. You want to ensure that it is not only functional but working at maximum capacity and efficiency. Especially during the summer months, your attic must be insulated and protected from the heat entering the space. Radiant barriers will reduce and reflect back the incoming heat, making your AC system work much less. This will ensure that your average electric bills are not drastically increasing and your home is safe from excess humidity and heat. An attic dehumidifier is also a great addition to ensure the relative humidity remains under a certain percentage. This will deter mold growth and assist your HVAC system. 

Radiant Barrier vs. Blown-In Insulation

One of the greatest questions we are asked is to explain the difference between radiant barrier installation and insulation blowing insulation. They are different not only in location but also function and use. As blown-in insulation is a very popular type of attic insulation, it’s important to understand when and why to use one versus the other. 

Blown-In Insulation

Blown-in insulation is loose-fill insulation. It is composed of different material types (you can choose between fiberglass and cellulose insulation). It has an r-value varying between R-2.2 and R-4.2 per inch depending on the material. It is installed by insulation blowing, whereby installers will take a large blower and literally blow the loose-fill pieces into the space. Blown-in insulation is beneficial in attics with hard-to-reach spaces, as the small pieces of insulation are blown in with a powered vacuum. It serves as a barrier, reducing the heat that enters and leaves the attic. Its unique characteristics allow it to absorb the heat as it enters. Its benefits include: 

  • Reduce energy costs 
  • Ensure comfortable indoor temperatures year-round 
  • Noise reduction 
  • HVAC efficiency 
  • Fights against moisture 

Radiant Barrier 

A radiant barrier, unlike insulation blowing, is installed by hand. It is not loose-fill, tiny pieces, but rather large, reflective material that is installed only in one location. Installed right under the roof in between the floor joists, the radiant barrier serves only one purpose: to reflect any heat that enters the attic. It is one of the best methods of insulating your attic, as its foil serves to ensure your attic (and therefore the rest of your home) remains at a constant, comfortable temperature.  As the radiant barrier is different from all other types of attic insulation, it does not have an R-value. It blocks and reflects the heat, rather than absorbing it. 

Are Radiant Barriers Worth It?

Based on our expert knowledge, we would confidently recommend installing radiant barriers in your attic space. However, we would encourage you to use it as a supplement rather than as the sole form of attic insulation. Its capabilities are great, but unique, making it an excellent means of reflecting heat and maximizing the efficiency of your attic space. Together with insulation blowing or foam board insulation, it can do wonders for your home and your average electric bills. Here in Charlotte, NC, summers get hot and humid. Protecting your home with an insulated attic, complete with a radiant barrier and even an attic dehumidifier would be a wise investment. Attic insulation, when properly installed, is a long-term solution, offering benefits for a minimum of 10 years. So have one of our specialists out for a free inspection. We will conduct a thorough inspection of your attic and discuss with you a custom solution for your home. Give us a call today!  

Good Home Insulation

We’re committed to saving you money and safely keeping your family comfortable all seasons of the year.

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