Metal Roof Heat: Absorbed or Reflected? Here’s the Truth!

Metal is a popular roofing material for many reasons: it’s extremely durable, tends not to worry about rot or infestation, and can protect roofs and homes from heavy snow and ice damming in the colder months. 

But what about the warmer months? If you’ve ever had the pleasure of sitting on a metal bench in a hot summer, you’d know that metal conducts heat better than most materials – and can get very warm if left out in the sun. So, the question is: does a metal roof absorb heat? Or does it reflect it? 

Metal Roof Heat: Will It Heat Up My Home?

The absorption properties of metal are irrelevant in modern day roofing. All roofs built to a modern standard are insulated, so the heat that the material absorbs is not necessarily going to transfer down into the home itself. 

On the contrary, metal roofing lends itself perfectly to specialized coatings that are unfeasible on other materials, such as clay or asphalt, meaning that metal roofs can be built to maximize their reflectivity, and thereby keep buildings cooler than any other roofing material. It’s for that very reason that the EPA champions metal roofs with reflective coatings – also known as cool roofs – to save energy in the hot months. The downside of a metal roof is that it can be more expensive to install than most other materials, may stain with time, and can be more difficult to install; which is why having a roofing contractor you can trust is vital. 

Myths and Misconceptions

Metal roofs are known for many myths and misconceptions, partially because older metal roofs aren’t built to the same standard as modern roof installations, and partially because of a misconception about the properties and benefits of a metal roof, and the different ways the coating of the roof can impact its practical uses and aesthetics. So, let’s delve into a few of these common myths and misconceptions. 

Metal roofs absorb heat and trap it in your home.

We’ve exhaustively discussed and explained why this first myth is wrong, but to recap – reflective coatings on a metal roof minimize heat by relaying the sun’s rays, thus keeping your interiors cool in the hot summer months. 

Metal roofs cause excessive moisture buildup due to condensation.

There is no danger of excessive moisture buildup in a metal roof. Insulation material used underneath the roofing, as well as standard ventilation, prevents any condensation problems. 

Metal roofs contribute to urban heat islands by heating up their surroundings.

In fact, the opposite is true. The EPA recommends metal roofs with high solar reflectance to keep heat away from a building, and explicitly avoid urban heat islands. This reduces the reliance on air-conditioning units during the hotter months of the year, cutting down on emissions and energy usage. 

Metal roofs only make sense in cold climates because they help with heat retention.

Metal roofs reflect heat in the summer, but they also insulate homes like any other good roofing material. They work all year round, and you don’t have to worry about losing any heat during the winter or losing any cool during the summer. 

All metal roofs have the same basic heat-absorbing properties, and the differences between material and finish are only minor.

Different levels of reflectivity in the coating can leave a roof with varying attributes, which can be useful relative to the climate and region the roof is installed in. For instance, cool roofs utilize a special reflective coating to minimize a building’s absorption of heat. Darker metal roofs reflect light less effectively but are often nicer to look at. 

Metal roofs are prone to corrosion, due to their exposure to the elements.

The coating used on all metal roofs leaves them protected against wind and water to a much greater degree than untreated sheet metal. Basic processes, such as galvanization, are used to keep metal roofs from corroding nearly as fast as untreated steel by coating the core material with zinc, or in some proprietary cases, with a mixture of zinc, silicone, and aluminum. This highly limits the material’s reactivity to water and air. It doesn’t do much for its reactivity to salt water, though, making metal roofs a less attractive option along ocean coastlines. 

Metal roofs are heavier than most other roofing materials.

The opposite is true – because metal roofs are such an efficient roofing material, each panel is often thinner and lighter than many other roofing materials, such as clay or slate. Metal roofing isn’t the lightest but is still considered a lightweight roofing material. 

Metal roofs make rain and hail noises much louder!

Your house is more than four walls with a collection of steel plates as a roof. A roof consists of multiple layers of material, including proper insulation to keep interiors cool during the warmer months, and warm during the cooler months. Proper insulation also helps mitigate any amplified sounds and noise concerns. While noise concerns were a greater issue in the past, that’s no longer the case with modern insulation standards. 

Metal roofs can be dangerous to work on in the summer due to their extreme heat.

While it can get hot on any roof during the summer months, metal roofs are not necessarily more dangerous to work on than other roofs due to their reflective coating. That being said, metal roofs can be more slippery than asphalt or stone roofs, so it’s still a good idea to follow safety protocols and wear a harness! 

Metal roofs make a home more susceptible to lightning strikes!

Electricity is famously lazy and will choose the path of least resistance to the ground – as well as the path that’s closest. Your roof isn’t grounded, meaning it won’t give lightning an easy time to ground. Furthermore, research has proven that metal roofs are no more likely to attract lightning than any other material – and because a metal roof is non-combustible, often with the highest degree of fireproofing of any roofing material, it may be one of the safest kinds of roofing materials to have in a lightning storm.  

Conclusion

While metal conducts heat better than stone or clay, reflective surfaces allow metal roofing to come out on top as the most energy-efficient option for hotter climates, by reducing the need for indoor cooling due to the ability to keep interiors from heating up. Understanding the mechanics of the metal roof heat can help you make an informed decision and choose the right roofing material for your home.

Want to know more about your various roofing options? Reach out to Piedmont Roofing today!