Short answer: Solar reflective paint for the roof, also known as heat reflective coating, is made with special pigments that reflect more sunlight. So, yes, they do work in preventing unnecessary heat buildup.
But how does it work exactly? This blog breaks down the science behind solar reflective paint. By the end of this blog, you will be able to decode the product label as well. Let us start by understanding the basics: how the temperatures of your roof and walls affect the indoor temperature?
How does roof temperature affect the indoor temperature?
Your roof plays a bigger role in indoor comfort than you might think. When the sun hits any surface (in this case, the roof), it delivers energy in three forms of light:
- UV light
- Visible light
- Infrared light
These forms of light are absorbed by the surface, causing it to heat up. When the roof becomes hotter than the indoor air, heat starts to move inward. This happens because heat always flows from a warmer area to a cooler one, according to the laws of thermodynamics.
The amount of heat absorbed by the roof directly affects indoor temperature. And that heat absorption depends largely on the material and colour of the surface.
Take a typical village mud house, for example. It stays cooler even without fans or AC. That’s because mud doesn’t absorb heat quickly. But, in today’s urban setup, concrete and metal are commonly used materials.
- Metal roofs heat up quickly due to their high thermal conductivity, but they also cool down rapidly after sunset.
- Concrete roofs absorb heat slowly but trap it for much longer. Even after sunset, they continue to radiate heat indoors, making nights warmer.
This is where solar reflective paint for the roof is useful.
What Is Solar Reflective Paint?
Solar reflective paint (also called cool roof paint or heat reflective coating) is made with special pigments that reflect sunlight, especially the infrared (IR) part of the spectrum, which carries most of the heat.
When applied to roofs, walls, or pavements, it tends to lower the surface temperature.
How does it work? The Science behind Solar Reflective Paint
Solar reflective paint is designed to reduce this heat gain. How? It works based on two principles: Solar reflectance and thermal emittance. Let us understand each of these properties in detail.
1. Solar reflectance – How much sunlight the surface reflects
The solar reflective paint contains reflective pigments (which give a white colour to the coating). These pigments bounce off sunlight instead of absorbing it.
Because of this, the surface stays cooler than it would have if it were coated with regular paint.
Albedo is a measure of reflectivity, ranging from 0 to 1. A high albedo paint has an albedo value closer to 1, meaning it reflects more sunlight and absorbs less heat.
2. Thermal emittance – How efficiently it radiates heat
When a surface absorbs heat, it doesn’t remain hot indefinitely. It gives off heat in the form of IR waves. Material with high thermal emittance doesn’t hold onto that heat. They release heat quickly and keep surfaces cooler.
Together, these two properties reduce the amount of heat a surface absorbs and stores. That’s why many coatings mention the “SRI” (Solar Reflectance Index), a combined score that reflects both.
What is SRI, and what does it tell you about heat reflective coatings?
Two surfaces might appear identical from the outside, but behave differently in sunlight due to SRI. SRI is calculated using a formula defined by the ASTM E1980 standard. It uses a reference roof surface (black and white) to compare temperature rise. To understand in layman’s terms,
SRI (Solar Reflectance Index) is a measure of two things:
- How hot a surface gets
- How cool it will stay in sunlight.
This means that higher SRI equals cooler surfaces under the sun.
Architects, engineers, and even building owners select materials that can reduce heat buildup, especially on the roof and walls. But how does roof temperature affect the indoor temperature?
But does cool roof paint technology matter?
- Reduces energy consumption and AC bills: Lower surface temperature means less heat enters the building. So, your air conditioning system doesn’t have to work as hard to maintain an optimum temperature, and your electricity bill drops significantly. This makes your building more energy-efficient.
- Reduces Urban Heat Island (UHI) effect: It is observed that cities are hotter than nearby rural areas. These solar reflective paints for the roof act as a solar heat reduction coating, trapping less heat and hence making the cities cooler.
- More Comfort: Working in non-AC places, such as warehouses or sheds, can be exceedingly miserable. These coatings can drop the inside temperature and improve employee well-being. Research by the U.S. Department of Energy shows that non-air-conditioned residential buildings can lower maximum indoor temperatures by 1.2–3.3 °C with cool roofs.
- Improves Roof Life: A roof under heat stress often cracks earlier. The solar heat-reducing paints for the roof reduce the thermal stress, leading to fewer repairs and a longer lifespan.
- Complies with Green building codes: Cool roof paint technology also supports sustainability standards such as LEED and IGBC. Novota’s Sunsheetal, a high-albedo, heat-reflective paint, has facilitated a cooler environment for over 250 green building projects.
Read More: Top 7 benefits of Heat Reflective Paint
Did you know: Heat-reflective coating is not only used on roofs, but also on pavements, vehicle rooftops, engines, and HVAC systems
Heat reflective paint for a greener tomorrow
The future of industrial coatings is green. High-albedo, heat-reflective paint is not only a key enabler of green buildings, but it also enhances the efficiency of solar panels, supporting smarter and more sustainable energy generation.
Conclusion
Heat reflective coatings work and support a sustainable, energy-efficient future. Whether you are building a new structure or upgrading an old one, applying these coatings is a simple step with long-term benefits: for your comfort, your wallet, and the planet.
At Novota Thermotech, we create Sunsheetal, a solar-reflective paint with the highest SRI of 108. Connect with Novota Thermotech to explore Sunsheetal for your commercial, industrial, or green building projects.
FAQs
Is heat-reflective paint the same as white paint?
Does cool roof coating work in humid or cloudy climates?
Cool-roof coating helps reduce surface temperatures in any weather conditions.
Can heat-reflective paint be applied to any roof?
Yes, it works on most roof materials, including concrete, metal, asbestos, and tiles. However, it is essential to prepare the surface properly before applying the paint. Read More:https://novota.in/importance-of-surface-preparation-for-industrial-coatings/
