Cool Metal Roofing: Benefits, SRI, and Cost Savings
By 
selkoshairi on September 9, 2024
Many people prefer cool metal roofing when building their steel structures. They are sustainable and conservative and bring in some cool monetary benefits.
A cool metal roof can reduce utility costs and benefit you and the environment. If you live somewhere with sizzling hot summer heat, it’s the best option that you can choose. With these, you can increase energy efficiency and the sustainability of your home or office.
In this article, we’ll discuss cool metal roofing, its benefits, and measurements. Also, we’ll debunk some old-school misconceptions regarding metal roofing. So, you can move past hesitation and make a quick decision for your home.
What is Cool Metal Roofing?
Cool metal roofing is a roofing system that has greater solar reflectance. These reflective roofs ensure lower heat even on hot days than conventional roofs. Their coating helps them reflect sunlight and dissipate heat.
Cool metal roofs can save total cooling costs and energy savings about 7 to 15%.
By the way, the cooling has nothing to do with the metal substrate as it is coating or paint applied during manufacturing that keeps the surface below it cool. The paint formula has new solar reflective pigments, which makes the primary difference.
Benefits of Cool Metal Roofs
Buildings and infrastructure in the urban areas are made of concrete that absorbs heat and stays warm for longer periods. But if you have reflective roofs, they can significantly reduce temperature and keep your home cool.
Cool roofing also lowers the electricity demand and reduces blackouts and power interruptions.
With lower energy use, cool roofing is a great way to reduce the emissions from power plants, such as carbon dioxide, sulfur dioxide, nitrogen oxides, and mercury.
Cool roofing comes under energy codes and green building rating systems in countries like the USA. They maintain records of these properties to verify and public reference.
Thus, the benefits of cool metal roofs in a nutshell are:
- Energy savings of up to 15%
- Reducing power outages
- Reducing power plant emissions
- Tax incentives
- Best alternative during hot weather
Common Measurements of Cool Roofing Systems
There are three major measurement terms for cool roofing, they are:
- Solar reflectance
- Emissivity (also known as thermal emittance)
- Solar Reflectance Index (SRI)
Solar Reflectance
Solar Reflectance (SR) is the ability of a material to reflect sun rays off its surface into the air and is measured within a range of 0 to 1. A surface that can reflect more than 55% of sunlight has a reflection of 0.55. Here, a roof with a higher SR means more reflection of the solar energy and cooler environment inside the building.
We measure SR in decimals on a scale ranging from 0 to 1, where 0 is the most authentic black while 1 is the purest white. Materials with dark color reflect less energy, between 5 and 20%, and light-colored roof materials reflect more, 55 to 90% energy, allowing the area below it to stay cool.
Emissivity
Emissivity is also known as thermal emittance. It measures the speed with which a surface emits heat before returning to normal temperatures. We measure it on a decimal scale ranging from 0 to 1, where 1 is the most efficient material. Thus, the higher it is, the more efficient it is at cooling itself.
Industries cite various emissivity levels as the minimum requirement for cool metal roofing. These levels could range between 0.70 to 0.85.
Solar Reflectance Index
In the roofing, road, paving, and construction industry, there is a metric called the Solar Reflectance Index (SRI), It is used to measure the solar reflectance and emissivity of a material. It is useful for measuring the radiation and heat reflected by a surface. SRI calculation is done on a scale of 0 to 100 where 0 signifies a darker or black surface and 100 indicates a whiter or brighter surface.
Roofs with SRI values of 75 or higher effectively mitigate heat transfer. Many cool metal roofing can achieve SRI values of over 85.SRI is difficult to define since it’s measured with a complicated formula. You can use an SRI calculator to measure your roof’s solar reflectance index.
Misconceptions About Metal Roofing
A few myths about metal roofing may make you hesitant and slow in your decision-making for a metal roof.
Let’s debunk some commonly held misconceptions about residential metal roofing.
Metal Roofs are Noisy
Some people think metal roofing makes loud noises during storms or rain. This myth comes from traditional tin roofs used in sheds and barns that can be quite noisy. But metal roofs of the present have solid sheathing and insulation to reduce the sound. The layers are soundproof and absorb the sound of hail, rain, and storms. You’ll find metal roofs quieter than asphalt shingles.
Metal Roofing Will Look Rusty and Old
When hearing about metal roofing, some people visualize a 100-year-old rusty outhouse. However, those are different from cool metal roofing used for modern homes. You can choose aluminum or steel roofing based on your project needs. However, aluminum is a better option in more harsh environments like the coastal regions.
Also, these metal roofs use coatings that offer additional protection from different elements. Thus ensuring the roof will not rust for a long time.
A cool metal roof has better longevity and endurance than other roofing options. Traditional roofing using Asphalt shingles usually lasts 20 to 30 years. On the other hand, metal roofs are more durable and last 50 years or more, giving better value for your investment.
They Attract Lightning
Some people fear metal roofs can increase the danger of lightning attacks or storms. This belief is likely rooted in the connection between electricity and metal. It’s the idea that roofs made of metal could act in the capacity of lightning magnets.
First of all, understand how lightning strikes. A mix of factors, like the structure’s height, shape, and isolation, attracts lightning. At the same time, it does not matter much what material is used in it. Lightning strikes are just as likely to hit a tree, utility pole, or roofing shingle as they are to strike a metal roof.
If lightning strikes an aluminum roof, it can disperse the electricity. Metal is not flammable and will disperse the electric charge over more of a large area. Metal roofs reduce the fire risk better than a combustible substance like wood in case of lightning.
Not Durable in Storms
If you buy metal panels in the shop, they’re thin and may even be able to bend. However, if it’s put in place correctly, it is quite robust and windproof.
In the aftermath of hurricanes, metal roofs are typically the most effective. It depends on the kind of panel selected and how it’s put up.
Cool metal roofing is also a popular choice for areas susceptible to wildfires. The metal roof won’t cause the flames even if an unintentional ember occurs.
Prone to Hail Damage
If the storm is strong enough to damage a metal roof, it’ll most likely damage asphalt shingles, too. When a powerful storm strikes, metal might dent but remain intact. Meanwhile, asphalt shingles may face severe damage and leaks. Also, certain insurance companies offer discounts for metal roofing.
Require More Attention
Maintenance for metal roofing is usually lower than that of other roofing materials. Although, it is important to inspect regularly for scratches or loose bolts. Also, you’d want to clean it occasionally.
Too Industrial
Suppose you’re familiar with cool roofing systems on commercial structures. In that case, Imagining what they’d look like in a house can be difficult. However, its versatility and sleek design make it a striking choice for even homes. They are also available in a wider range of colors, from white to almond, emerald green, and royal blue.
Metal Roofs Color Options
Selecting the appropriate colors of steel panels can enhance your roof’s energy efficiency. The right colors reflect the sun’s energy off the roof better than others.
If you choose the right combination of coating and color, you can create an attractive steel roof. An attractive cool roof that is both sustainable and can keep your place cool. We’ll suggest colors like bone white, polar white, and snow white for better cooling.
Many other attractive, eye-catching colors like matte black, bronze, and gray exist. They provide a modern and luxurious appeal and complement most other colors. However, the issue is that these colors have low SRI numbers, as low as 20 to 30. They won’t be able to reflect and release much heat off their surface.
Energy Efficient Cool Metal Roofing
Metal is now a primary material used in cool roofing due to its durability. There are numerous ways cool roofing systems can be energy efficient, including:
- Energy savings between 7% and 15%
- Tax incentives
- Reduce the use of air-conditioners
- Fire resistance
- Low maintenance
- 40 to 60 years of longevity
Conclusion
Cool roofing systems are gaining popularity as a sustainable and energy-efficient construction material. You can often see them on commercial, residential, and government-owned properties.
The best part of cool roofing is that it cools down the temperature, even on scorching hot days. It can also help you save utility costs and reduce energy consumption.
Apart from its benefits, we also debunked some old, deep-rooted misconceptions regarding metal roofing. Metal roofing can be better than asphalt shingle or wood, even during rain, storm, lightning, or fire. They can last as long as 40 or 60 years with little maintenance.
If you live or work in a sizzling hot area and want to reduce energy costs and be green, consider cool metal roofing.
Frequently Asked Questions (FAQs)
How does cool metal roofing work?
Cool metal roofing has a special coating or paint with high solar reflectance and thermal emittance. This coating reflects sunlight and dissipates heat.
How much cost can we save on energy bills?
You can save between 7% and 15% on cooling costs with cool metal roofing.
How does the color of the metal roof affect temperature?
The color of the metal can influence its SRI. Lighter colors like white reflect more sunlight and keep the building cooler. Darker colors absorb more heat and are less effective at cooling.
How can a cool metal roof reduce power outages?
Since you’ll live or work in a cooler building, electricity demand is reduced. Thus, there will be fewer power interruptions and blackouts.
How long does this metal roofing last?
Metal roofings are quite durable. With proper maintenance, it can last up to 40 to 60 years.
Are metal roofing fire-resistant?
Yes, they are fire-resistant. Thus, factories dealing with flammable objects prefer reflective roofs for better safety.
What maintenance should we provide?
It requires minimal maintenance. All you need to do is regularly inspect for any damage or debris and occasionally clean.
Can we use metal roofing in cold climates?
Cool metal roofing is generally best in hot climates where cooling costs are an issue. However, you can install metal roofing in cooler climates too. Its performance and benefits may differ depending on the weather conditions.
