Maximizing Energy Efficiency: The Benefits of Metal Roofs

Interlock's reflective aluminum roofing bounces more of the sun's heat away than dark asphalt; actual savings depend on climate, color, insulation and ventilation. Paired with a lifetime warranty, Class A fire rating, and 120 mph wind resistance, it's an energy upgrade that protects your home for decades.

Your roof is the largest sun-facing surface on your home — and the material you choose quietly decides how hard your air conditioner works every summer.

Most homes are topped with dark asphalt shingles that absorb solar radiation and re-radiate it downward into the attic, where temperatures can climb well past 150°F on a hot day. That trapped heat migrates into living spaces and forces your cooling system to run longer and harder. A reflective metal roof flips that equation.

Interlock builds its lifetime aluminum roofing systems around a reflective finish called Alunar®, engineered to reflect the sun's heat rather than store it. The result is a roof that reflects more of the sun than dark asphalt while shrugging off fire, wind, and impact — and lasting a lifetime. Several of Interlock's colors carry a Cool Roof Rating Council rating, with published solar reflectance and thermal emittance values.

How does a metal roof improve energy efficiency?

A metal roof improves energy efficiency mainly through reflectivity. Interlock's Alunar® reflective finish reflects more of the sun's radiant heat than dark asphalt, lowering attic temperatures. Because aluminum also sheds heat quickly after sunset, your home stays cooler longer than it would under heat-absorbing asphalt shingles.

What "Energy Efficiency" Actually Means for a Roof

Roofing energy efficiency comes down to two measurable properties: solar reflectance (how much sunlight the surface bounces away) and thermal emittance (how quickly it releases any heat it does absorb). A roof that scores high on both stays cooler in direct sun and cools down faster afterward — the definition of a "cool roof." The Cool Roof Rating Council (CRRC) publishes these values for rated products. Dark asphalt shingles sit near the bottom of this scale.

How Interlock's Reflective Alunar® Finish Saves Energy

Every Interlock roof is finished in Alunar®, a high-performance PVDF (Kynar 500®-class) fluorocarbon coating applied to both sides of the panel. Several colors are rated by the Cool Roof Rating Council: initial solar reflectance ranges from 0.25 up to 0.44 (Aged Copper is highest), with thermal emittance of 0.83 to 0.86. Those two numbers are what matter. Reflectance keeps a share of the sun's radiant energy from ever entering the attic, and the 0.83 to 0.86 emittance means the roof releases the heat it does absorb almost immediately once the sun moves off it.

Why Aluminum Outperforms Heat-Absorbing Shingles

The advantage starts with the metal itself. Aluminum is naturally reflective and lightweight, and it doesn't store thermal energy the way a dense, dark asphalt mat does. Combined with the reflective Alunar® finish and the airspace created by Interlock's interlocking panel design, the system limits both radiant and conductive heat transfer into the structure. Asphalt, by contrast, is petroleum-based and dark by default; it bakes in the afternoon sun and bleeds that heat indoors for hours.

Energy Efficiency Meets Solar: A Roof Built to Power Your Home

An efficient roof and on-site solar are natural partners. Interlock systems are engineered to be solar-ready: the panels are strong enough to carry a PV array, and the roof is designed to last longer than the panels mounted on it — so you never face the expensive remove-and-reinstall cycle that happens when a solar array outlives a conventional roof beneath it.

Efficiency You Don't Have to Replace: Durability as Sustainability

The greenest, most efficient roof is the one you never have to tear off and send to a landfill. An Interlock roof is built to last 50 years or more — up to three times the lifespan of asphalt — which means a single install instead of two or three re-roofs over the same period. That longevity is backed by hard performance: a Class A fire rating, resistance to winds up to 120 mph, and UL 2218 Class 4 impact resistance. That same durability-as-sustainability logic is at the center of Interlock's broader case for investing in a sustainable future.

The Bottom-Line Payoff

Energy efficiency is rarely the only reason homeowners choose Interlock, but it's one of the most immediate: a reflective roof starts working the first summer. Layered on top are decades of avoided maintenance, a transferable lifetime warranty, and the resale appeal of a permanent, energy-smart roof. This article was independently reviewed by Robert Scichili, a founding board member of the Cool Metal Roofing Coalition and a published authority on LEED and cool metal roofing.