LO/MIT Radiant Barrier: Optimize Your Home's Energy Efficiency

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WHAT IS LO/MIT®?

LO/MIT® is a non-thickness-dependent, low-emissivity coating designed to significantly reduce the emissivity of the surfaces it covers. When applied correctly, it functions as an effective radiant heat barrier.

LO/MIT coatings are classified as interior radiation control coating systems (IRCCS) under ASTM standards, making them ideal for use as radiant-barrier systems when properly installed.

Why does that matter?

The lower the emissivity, the less radiant heat a surface emits. This is precisely where LO/MIT comes in.

☀️ HOW DOES LO/MIT® WORK?

In regions like Texas, your roof is subjected to intense sun exposure. As the roof deck heats up, that heat radiates towards cooler surfaces in your attic. LO/MIT transforms the surface of your roof deck by significantly lowering its emissivity, which in turn reduces the amount of radiant heat that can pass down into the attic.

Imagine this:

Texas sun → hot roof → radiant heat → attic

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LO/MIT creates a low-emissivity surface

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Less radiant heat is transferred into the attic

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A cooler attic and a more comfortable home

🛡️ WHAT IS A RADIANT BARRIER?

Heat can move through a building in three ways:

CONDUCTION: Heat moving through solid materials.

CONVECTION: Heat moving through the air.

RADIATION: Heat traveling as electromagnetic energy from one surface to another.

While traditional insulation primarily addresses conduction and convection, an IRCCS or radiant barrier effectively manages radiant heat transfer.

ASTM defines an interior radiation control coating system (IRCCS) as a material with an emissivity of 0.25 or less. Conversely, a radiant barrier meets the ASTM definition with an emissivity of 0.10 or less.

🌡️ WHAT IS EMISSIVITY?

Emissivity measures how effectively a surface emits thermal radiation, ranging from 0 to 1. A higher value indicates greater capability for emitting radiant energy. For instance, untreated wood has an emissivity of about 0.72. LO/MIT can reduce the surface emissivity of eligible materials to approximately 0.24–0.15 or lower, depending on specific product and application.

Lower emissivity results in reduced radiant heat transfer.

📏 DOES LO/MIT HAVE AN R-VALUE?

Not in the classic sense. R-values are typically used to indicate the efficacy of insulation against heat transfer. Since radiant barriers and IRCCS focus primarily on radiant heat transfer, their function is different. However, LO/MIT can complement traditional insulation effectively. For example, LO/MIT applied alongside R-19 insulation can achieve overall heat-influx performance equivalent to about R-34 in certain conditions.

The key takeaway is that radiant barriers and insulation can work synergistically rather than being mutually exclusive.

🏠 WHERE DOES THE AIRSPACE COME IN?

This aspect is crucial for optimal performance. For a radiant barrier or IRCCS like LO/MIT to work effectively, the low-emissivity surface must face an airspace of at least 2 inches. This requirement explains why the underside of a roof deck is a particularly suitable application location.

Roof deck

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LO/MIT low-emissivity surface

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Attic airspace

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Attic insulation

If insulation is placed directly against the LO/MIT surface without the necessary airspace, the radiant-barrier effect could be compromised.

🏡 DOES LO/MIT HURT MY ROOF SHINGLES?

According to the manufacturer’s information, it doesn’t. Testing conducted, including at the Florida Solar Energy Center, found that the use of radiant barriers or IRCCS like LO/MIT resulted in a minimal increase of around 2–5°F in shingle temperature.

⏳ DOES LO/MIT LOSE EFFECTIVENESS OVER TIME?

The manufacturer asserts that LO/MIT retains its low-emissivity characteristics over time. Reports indicate that experimental samples installed over 25 years ago have maintained their low-emissivity levels. Additionally, LO/MIT isn’t a sheet material, which means it isn’t prone to tearing and delamination issues often seen in some traditional radiant barrier products. There’s no need for routine re-coating.

💧 DOES LO/MIT TRAP MOISTURE?

No, it doesn’t. LO/MIT is engineered to allow water vapor to permeate rather than creating a vapor-impermeable layer over the roof deck. This permeability means that in the event of a roof leak, moisture can still escape, allowing for detection and repair. The manufacturer also confirms that LO/MIT will not delaminate even if roofing nails penetrate the decking during re-roofing.

🧱 CAN LO/MIT BE USED ON WALLS?

Yes, it can. However, the manufacturer notes that LO/MIT is generally most effective when applied beneath roofs, as roof surfaces tend to reach higher temperatures than walls. In warmer climates, especially where sidewall insulation is limited, LO/MIT can also enhance interior comfort.

🏗️ CAN IT BE USED IN OTHER APPLICATIONS?

Absolutely. The manufacturer indicates that LO/MIT has versatility and can be used in:

- Residential attics  

- Commercial buildings  

- Vent-skin roof assemblies  

- Vent-skin sidewalls  

- Areas behind radiant heating systems  

- Certain sidewall applications  

- Other suitable non-porous building surfaces  

Installation and assembly requirements can vary, so Area 361 evaluates each project on a case-by-case basis.

🌬️ WHAT ABOUT ATTIC VENTILATION?

It remains a crucial factor. While radiant barriers like LO/MIT address radiant heat, ventilation plays a vital role in managing both heat and moisture through convection and air movement. They represent different components of a holistic attic system, which is why Area 361 considers the attic as a whole rather than simply applying a coating and concluding the job.  

Radiant Defense + Proper Ventilation + Proper Insulation = A Better-Performing Attic

🔥 DOES IT HELP WITH HEATING?

It can contribute to heating, but radiant barriers and IRCCS products like LO/MIT are generally more effective at mitigating cooling loads compared to heating loads. In regions such as the Coastal Bend, where summer heat can be intense, this distinction is particularly relevant.

🌿 IS LO/MIT LOW-VOC?

LO/MIT-II and LO/MIT-II MAX qualify as water-based, low-VOC formulations. The manufacturer confirms these products comply with the VOC limits set by the California EPA Air Resources Board’s Architectural Coatings Program. Safety is paramount; therefore, professional application should include adequate ventilation and personal protective equipment, including recommended respiratory protection and protective clothing.

👽 WHY AREA 361?

We don’t just spray a silver coating in your attic and leave you in the dark. We assess, we explain, we provide quotes, and you make the final decision. Our straightforward process includes:

1. FREE CONSULTATION - We evaluate your attic and share our findings.

2. HONEST QUOTE - You receive a clear quote with no obligation.

3. YOU DECIDE - No pressure, no awkward sales pitch, no harassment.

4. RADIANT DEFENSE - Should you choose Area 361, we apply the system professionally in accordance with the manufacturer’s guidelines.

Reflect the Heat. Protect Your Home.

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Technical Information:

Product performance, application requirements, and technical specifications are based on information from the manufacturer and may vary depending on the substrate, installation conditions, and building assembly. Area 361 Radiant Defense does not guarantee specific energy savings or temperature reductions. Always consult current manufacturer technical documentation for installation requirements.