Authored by: Rimkus Built Environment Solutions Marketing Team
Published 5/29/2026
Energy costs climbed year over year across a 30-property portfolio, despite stable occupancy. The facilities director traced the spike to aging dark roofing membranes absorbing heat across single-story retail and warehouse assets in warm-climate markets.
According to the U.S. Environmental Protection Agency (Using Cool Roofs to Reduce Heat Islands), buildings with cool roofs absorb less solar heat, use less air conditioning, and stay more comfortable indoors. A cool roof reflects more sunlight than a standard dark roof, so it absorbs less heat.
Roof surface temperature, aged reflectance, local code requirements, and re-roofing timing all factor into whether a cool roof fits a given property, and the sections below walk through each.
Key Takeaways: How cool roofs may affect commercial property operations
A cool roof reflects more sunlight than a conventional dark roof, so less heat reaches the space below. For low-slope commercial buildings in warm climates, that can lower cooling demand and may be required by energy code.
What a cool roof does:
- A cool roof reflects sunlight and stays markedly cooler than a dark membrane.
- Reduced rooftop heat gain can lower cooling energy use, trim peak demand charges, and help extend membrane life.
- Energy codes like ASHRAE 90.1 and the IECC require cool roofs on many low-slope buildings in hot climate zones.
How to approach it:
- Net savings are strongest in cooling-dominated climates and narrow in heating-dominated ones, where modeling beats regional rules of thumb.
- Specifying a cool roof at a scheduled re-roofing is typically the most cost-effective path.
- Compliance and savings estimates rely on three-year aged reflectance values, not initial values.
For portfolio-specific guidance, Contact Us to discuss cool roof evaluation.
Cool roof basics
A cool roof reflects more sunlight and absorbs less solar energy than a conventional roof. The U.S. Department of Energy (DOE) defines it as a roof that absorbs and transfers less heat from the sun to the building below.
Two properties generally influence cool roof performance. Solar reflectance measures how much sunlight a surface bounces back, on a scale of 0 to 1.0: dark conventional roofs reflect only a small fraction of incoming sunlight, while cool roofs reflect a much larger share.
Thermal emittance measures how efficiently a surface releases absorbed heat. Nearly all nonmetallic roofing materials already release absorbed heat efficiently, so how much sunlight a roof reflects is the property that most sets a cool roof apart. A conventional dark roof can reach 150°F or more on a hot summer day, while a cool roof can stay more than 50°F cooler.
Cool roof benefits for commercial properties
Cool roofs may help reduce cooling energy consumption, lower peak electricity demand, and extend roof membrane life. Reported energy savings vary widely by building type and climate, so building-level estimates are more reliable than generalized averages.
Peak demand reduction may lower monthly utility bills for properties subject to demand charges.
Cool roof types and materials
Cool roof products span low-slope and steep-slope applications. Material selection depends on roof slope, substrate condition, and project type. Product type can also affect whether a project is better suited to replacement or retrofit.
Low-slope (flat) roof options
The Cool Roof Rating Council (CRRC) classifies low-slope roofs as those with a pitch of 2:12 or less. Low-slope roofs are the dominant configuration for commercial, industrial, and office buildings. Manufacturers typically produce thermoplastic polyolefin (TPO) and polyvinyl chloride (PVC) single-ply membranes in white, making them inherently reflective without additional surface treatment. Modified bitumen systems can achieve cool roof performance through reflective top layers, coatings, or surface granules.
Liquid-applied coatings are a primary retrofit option for existing commercial roofs, offering high initial solar reflectance without replacing the membrane.
Steep-slope roof options
Steep-slope roofs (pitch of 2:12 or greater) appear on office fronts, retail buildings, and mixed-use commercial assets. Cool-rated asphalt shingles use solar-reflective ceramic granules to raise reflectance, and concrete tiles can reach higher values. Metal roofing spans both slope categories, with reflectance depending on factory-applied coatings.
Field-coating previously installed asphalt shingles can create moisture-retention issues and may void the manufacturer’s warranty.
Cool roof ratings, standards, and codes
Three frameworks can provide guidance on cool roof product verification and building code compliance. CRRC tests and publishes initial and three-year aged values for solar reflectance, thermal emittance, and Solar Reflectance Index (SRI) in its product directory.
ASHRAE 90.1 and the IECC both include cool-roof requirements for low-slope commercial buildings over cooled spaces in Climate Zones 0 through 3, with compliance options including a minimum three-year aged solar reflectance of 0.55 and thermal emittance of 0.75 or an aged SRI of 64.
California Title 24 sets stricter thresholds. Nonresidential low-slope roofs require an aged solar reflectance of 0.63 or greater across all 16 California climate zones, not just the warmest ones.
ENERGY STAR sets a minimum aged solar reflectance of 0.50 for low-slope products and 0.15 for steep-slope products. ENERGY STAR certification can support utility rebates, and some ENERGY STAR-certified roofing products may also help contribute toward Leadership in Energy and Environmental Design (LEED) heat island reduction credits when they meet the required solar reflectance or SRI thresholds.
Climate and regional considerations for cool roofs
Cool roofs can produce net energy savings across most of the continental United States, but the magnitude varies by climate zone. Lawrence Berkeley National Laboratory (LBNL) energy modeling found that cooling savings can offset winter heating penalties across many of the climates studied.
Cool roofs may also help reduce the urban heat island (UHI) effect by lowering rooftop surface temperatures across dense commercial districts. The EPA describes cool roofs as one of several key strategies for reducing urban heat islands, which raise ambient air temperatures in built-up areas above those of surrounding rural land.
ASHRAE Climate Zones 1 through 4 show the strongest net savings. Zones 5 through 8 produce narrower or variable results, and building-level energy modeling provides more reliable projections than regional averages where the heating penalty may exceed cooling savings.
Signs a property may be a candidate for a cool roof
Single-story buildings with large roof areas relative to conditioned floor space, such as warehouses, big-box retail, and light industrial facilities, may see the greatest cooling energy reductions, because the roof can be a dominant heat-gain surface.
Several indicators signal a strong cool roof candidate:
- The property is located in ASHRAE Climate Zones 1 through 4
- The existing roof is dark-colored with no reflective properties
- The building has significant air conditioning costs or high utility demand charges
- The roof is at or near the end of its service life
- Current roof insulation falls below code requirements (below R-20 in most zones)
Buildings with below-code insulation may benefit more from a cool roof because the roof surface can have a greater influence on interior heat transfer.
Maintaining cool roof performance over time
Cool roof maintenance is similar to conventional roof maintenance, with reflectance monitoring as the primary added task. Most reflectance loss occurs within the first one to two years after installation, then stabilizes.
Cleaning with detergent (and algaecide where needed) may restore up to 90% of original reflectance on most roofs. Power washing and harsh chemicals can damage membranes. Cleaning triggered by measured reflectance loss can provide better return than fixed annual schedules.
Cool roofs in capital planning
Specifying a cool roof at the scheduled re-roofing event in a capital improvement plan is typically the most cost-effective approach. Studies that account for price premiums, heating penalties, cooling savings, and extended roof life have generally found net positive savings over a roof’s service life in cooling-dominated climates.
State and local utility programs in many jurisdictions offer rebates for cool roof installations. LEED heat island reduction credits and ENERGY STAR benchmarks can support the investment case for properties pursuing green building certification or environmental, social, and governance (ESG) reporting goals.
Building envelope assessments and property condition assessments can help provide baseline data to support more reliable timing of cool roof investments within five- or 10-year capital projection windows.
Bringing cool roof strategy into long-term asset planning
Low-slope commercial buildings in Climate Zones 0 through 3 are the most consistent candidates when large roof areas sit above cooled conditioned space. Capital plans should account for climate zone, roof area, cooled space, and code requirements before material specifications are finalized.
Experienced building envelope professionals can review roof slope, substrate condition, code compliance, and capital timing for properties across different climate zones.
Contact Us to speak with a qualified expert about cool roof evaluation and capital planning for commercial properties.
Frequently asked questions about cool roofs
Do I need a cool roof to comply with energy codes?
It depends on location and building type. Under ASHRAE 90.1 and the IECC, cool roofs are required on low-slope commercial buildings over cooled conditioned space in Climate Zones 0 through 3. Many states adopt these codes or stricter versions: California Title 24 requires an aged solar reflectance of 0.63 for nonresidential low-slope roofs in all 16 climate zones. Outside mandated zones, a cool roof is not required by code but may still be the most cost-effective choice at the scheduled re-roofing event. Before specifying a replacement membrane, checking the code edition adopted in the building’s jurisdiction confirms whether a cool roof is required and which reflectance threshold applies.
What is the best cool roof material for a commercial low-slope roof?
For most commercial low-slope roofs, TPO and PVC single-ply membranes in white are the most common and cost-effective cool roof choice. Manufacturers produce them inherently reflective, and they typically achieve aged solar reflectance values well above the 0.55 ASHRAE 90.1 minimum. Liquid-applied coatings are the primary retrofit option for existing roofs where replacing the membrane is not yet warranted. Modified bitumen systems can achieve cool roof performance through reflective cap sheets or coatings. The best material for a specific property depends on the existing roof type, substrate condition, climate zone, and whether the project is a full replacement or a retrofit.
How do I know if my building qualifies for a cool roof rebate?
Many state and local utility programs offer rebates for cool roof installations, particularly in warm-climate states. Eligibility typically depends on the product meeting a minimum aged solar reflectance, often the ENERGY STAR threshold of 0.50 for low-slope roofs, and the project being a qualifying replacement or new installation. ENERGY STAR certification can support rebate applications, and some jurisdictions tie rebates to CRRC-rated products specifically. The most direct path is to check with the local utility or state energy office before specifying the product, since rebate programs change frequently and some require pre-approval.
This article is intended to provide general information and insights into prevailing industry practices. It is not intended to constitute, and should not be relied upon as, legal, technical, or professional advice. The content does not replace consultation with a qualified expert or professional regarding the specific facts and circumstances of any particular matter.