Would you like your home to remain cool and comfortable, even on the hottest summer days, without cranking up the air conditioning? Try cool roofs.
A cool roof absorbs less of the sun’s energy than a conventional roof, reducing the amount of heat transferred into a building.
In this guide, we’ll explore cool roof benefits and other crucial details to help you decide if it’s the right solution for your energy savings and eco-conscious goals.
If you want to learn more about cool roofs directly from an expert or are considering installing them, contact Viking Contractors LLC now.
What Are Cool Roofs?
A cool roof is made of materials or has coatings that reflect sunlight and absorb less heat. They’re typically lighter in color than conventional roofs and may contain special reflective materials.
There are two primary properties that determine the coolness level of a roof.
- Solar Reflectance: This is the ability of a material to reflect sunlight away from its surface instead of absorbing it. Lighter colors have higher solar reflectance than darker colors. For instance, a white roof has a higher solar reflectance than a black roof.
- Thermal Emittance: This measures how effectively a roofing material releases the infrared radiation (heat) it has absorbed. A material with a high thermal emittance will emit heat more efficiently, while one with a lower emittance will retain heat more.
The most effective cool roofs have high solar reflectance and thermal emittance values.
Cool Roof Benefits for Building Owners
As a property owner, here are the benefits cool roofs could bring you:
Reduced Energy Costs
Cool roofs lower the air conditioning needs by reflecting sunlight away from the building, absorbing less heat, and releasing the absorbed infrared radiation. The reduced use of air conditioners leads to lower energy bills.
Improved Comfort and Health
A cool roof helps to keep indoor temperatures cooler, even in hot weather. Improved air quality results in comfort and health safety, including in spaces with undersized HVAC systems or that aren’t air-conditioned.
In fact, cool roofs can lower non-air-conditioned residential building temperatures by 1.2 to 3.3°C.
Extended Roof Life
Below are some of the reasons why cool roofs have an extended lifespan:
- Reduced Thermal Stress. The reduced heat absorption (temperatures) means less expansion and contraction, reducing wear and tear.
- Diminished UV Exposure: Ultraviolet (UV) radiation from the sun can damage roofing materials, leading to cracks, fading, and other forms of roof damage. Cool roofs reduce the extent of UV exposure, which reduces such damage.
Money Saving Rebates and Other Financial Incentives
Installing cool roofs can help you qualify for rebates from the government, NGOs, energy providers, and utilities programs. Such programs are typically part of broader initiatives, for instance:
- Energy efficiency
- Green buildings
- Climate change mitigation
Each program has its qualification requirements that consider the following factors:
- Roof slope
- Cool roof materials
- Solar reflectance
- Thermal emittance values
- Property type (commercial, residential, etc.)
You can find relevant rebate programs and incentives on the Cool Roof Rating Council website. Here are some examples:
- Rebate Program: Energy Cool Rebate program in San Antonio, Texas
- Loans to Cover Installation and Maintenance Costs: Energy Conservation for Ohio
- Entire Building Incentives: Customized Retrofit Incentives from Pacific Gas and Electric
Cool Roof Benefits for Society and Environment
If you’re environmentally conscious, you’ll probably want to install cool roofs because of the following benefits:
Reduced Air Pollution and Greenhouse Gas Emissions
A high electricity demand involves burning fossil fuels, which contributes to air pollution and greenhouse gas emissions.
With reduced air conditioning needs, power plants burn less fossil fuels, leading to lower emissions and air pollution.
Reduced Peak Electricity Demand
When cool roofs are installed across a city, there could be a significant reduction in cooling energy use. This reduces peak electricity demand (hours when electricity consumption typically surges), preventing power outages caused by system overload.
Urban Heating Mitigation
The urban heat island effect is a phenomenon in which urban areas are warmer than surrounding rural areas due to buildings and other infrastructures. Cool roofs help to maintain lower local temperatures by reflecting sunlight away from buildings.
Mitigating heat islands reduces the associated adverse effects like heat-related mortality.
When applied on a large scale, they can even decrease the formation of ground-level ozone, a harmful air pollutant that is heat-dependent.
How to Make Your Roof Cool: Types of Cool Roofs
There are two main types of cool roofs:
- Inherently Cool Roofs: These are roofs made of naturally reflective materials, such as white tiles.
- Cool Roof Coatings: These are coatings that can be applied to existing roofs to make them more reflective.
Various types of roofing materials offer cool roof options, from asphalt shingles and concrete tiles to slate tiles.
Products for Steep Roofs
Here are some cool roof products for a steep-slope design:
- Asphalt Shingles
- Polymer Shingles
- Wood Shingles
- Clay Tiles
- Slate Tiles
- Concrete Tiles
- Metal Shingles or Tiles
Products for Low-Sloped Roofs
Meanwhile, here are the products suitable for low-sloped roofs:
- Green (vegetative) roofs
- Built-up roofs
- Single-ply membranes
- Modified Bitumen sheet membranes
- Spray polyurethane foam roofs
Should You Install a Cool Roof?
Here are the factors to consider when choosing and installing a cool roof:
- New Home vs. Existing Roofs: If you’re installing a new roof to a new home or during renovation, consider an inherently cool roof. A roof coating or green roof might be more budget-friendly for an existing roof in good condition.
- Lifespan: Inherently cool roofs have a longer lifespan than coatings. But note that the roofing material used determines the roof’s lifespan, so choose wisely.
- Moisture Control: Cool roofs may be more susceptible to algae and mold growth in warm, moist environments than dark roofs. It’s best to choose those that are chemically treated to prevent mold growth in such locations.
- Thermal Emittance and Surface Solar Reflectance: The higher the values, the cooler the roof will stay.
Installing Cool Roofs in Cold Climates
A cool roof can result in a winter heating penalty. It refers to the increased energy consumption required to heat a building with a cool roof during winter. That’s because cool roofs absorb heat less efficiently during the winter.
However, the energy savings during summer often offset the heating penalty. The lower sun angle and shorter days during winter also make the effect insignificant, as there’s not much sun heating anyway.
You can also limit winter heating penalty and maximize energy savings by adding effective insulation/air sealing and considering energy-efficient designs.
How Much Difference Does a Cool Roof Make?
Cool roofs significantly affect cooling energy savings, indoor comfort, and environmental impact.
How Long Does a Cool Roof Last?
A cool roof’s lifespan depends on the material used, installation process, climate, and maintenance.
How Much Do Cool Roofs Cost?
Cool roofs’ cost is competitive with traditional materials and varies by product type.
Installing cool roofs has many benefits. It can help lower energy bills, improve indoor comfort, extend the roof’s lifespan, reduce air pollution, and prevent urban heat islands.
Do you see how a cool roof will benefit your home or commercial building? Schedule a free consultation with us today. We’ll help you choose the appropriate cool roofing products, answer your questions, and install the roof professionally.