Do Radiant Barriers Work? - LP Techshield Review

Summary

In this video, Jordan Smith explains the function of radiant barriers, focusing on the LP TechShield radiant barrier integrated with OSB sheathing. He discusses how heat is transferred through conduction, convection, and radiation, and demonstrates the effectiveness of the radiant barrier using an infrared thermometer. Jordan emphasizes the importance of maintaining an air gap for optimal performance and highlights how improper insulation, like spray foam, can negate the benefits of the barrier. He concludes by encouraging viewers to consider the full system when using radiant barriers for energy efficiency.

Takeaways

• 🛠️ The video is about radiant barriers, specifically LP Tech Shield, which is integrated into OSB sheathing to reduce heat transfer.
• 🌞 Heat transfers in three ways: conduction, convection, and radiation. Radiant barriers address heat transfer by radiation.
• 🌡️ The speaker uses an infrared thermometer to show a 10-degree temperature difference on a westerly-facing roof, demonstrating the radiant barrier's effect.
• 🏠 In summer, the radiant barrier is more effective as it blocks more radiative heat from the sun.
• 🚧 Conduction happens when heat transfers through solid materials, like rafters in a roof, reducing the effectiveness of radiant barriers at those points.
• 🛑 Radiant barriers require an air gap behind them to function properly; without this, they lose effectiveness.
• 💡 Insulation choice is crucial. For example, fiberglass insulation with an air gap maintains the barrier's efficiency, while spray foam negates it by creating conduction.
• 🔄 The speaker emphasizes the importance of designing the entire system to complement the radiant barrier for optimal performance.
• 📐 Advanced framing techniques can help reduce heat conduction through rafters, further improving energy efficiency.
• 📱 The speaker encourages viewers to subscribe, follow on Instagram (@JordanSmithBuild), and ask questions for further information.

Q & A

What is a radiant barrier and how does it work?

A radiant barrier is a material, like the LP TechShield discussed in the video, that reflects radiant heat away from a space. It consists of a reflective surface, such as aluminum, that reduces heat transfer by radiation.

What are the three ways heat is transferred?

Heat is transferred through conduction, convection, and radiation. Conduction is heat transfer through direct contact, convection involves the movement of hot air or fluids, and radiation is heat transfer through electromagnetic waves.

How does the LP TechShield radiant barrier reduce heat transfer?

The LP TechShield radiant barrier reduces heat transfer by reflecting radiant energy away from the space, preventing it from heating the area below. This is achieved through the aluminum layer integrated into the OSB sheathing.

What role does the air gap play in the effectiveness of a radiant barrier?

The air gap is crucial because it prevents direct contact between the insulation and the radiant barrier. Without an air gap, the heat would conduct into the insulation, reducing the effectiveness of the radiant barrier.

Why does spray foam insulation negate the effectiveness of a radiant barrier?

Spray foam insulation, when applied directly to the roof deck, negates the radiant barrier's effect by conducting heat from the roof deck into the insulation. Without an air gap, the radiant barrier cannot reflect heat properly.

Why is it important to spread rafters apart in advanced framing?

Spreading rafters apart in advanced framing reduces the amount of heat conduction through the rafters, which helps maintain the effectiveness of the radiant barrier by minimizing heat transfer through the framing.

How does an infrared thermometer help in demonstrating the effectiveness of the radiant barrier?

An infrared thermometer measures radiant energy, showing how much heat is being emitted from a surface. In the video, it demonstrates the temperature difference between the radiant barrier and non-barrier areas, indicating how much heat is being reflected.

What temperature differences did the speaker measure during the demonstration?

The speaker measured a 10-degree difference between the westerly facing wall and roof deck, which indicates that the radiant barrier is reflecting heat away even on a relatively cool day.

Why is it necessary to design a building system to take advantage of a radiant barrier?

A radiant barrier only works effectively if the building system is designed to allow it to reflect heat. This includes maintaining an air gap and minimizing direct conductive paths like rafters or certain types of insulation.

What are the potential consequences of installing insulation incorrectly with a radiant barrier?

If insulation is installed incorrectly, such as placing it in direct contact with the radiant barrier, the radiant barrier will not work properly, and the heat will conduct into the insulation and potentially into the living space below.