Pictured: NYC CoolRoofs trainees coat a rooftop with white reflective paint. Photo credit: NYC Mayor's Office of Climate & Environmental Justice
June 28, 2024 - The Metro Mayors Region is beating the summer heat with cool roofs (also known as white or reflective roofs) to reduce indoor temperatures, save on energy costs, and improve comfort of homes, schools, and other buildings. MAPC compiled a Cool Roofs Educational Toolkit that details the basics and benefits of cool roofs. The Toolkit includes FAQs, factsheets, and social media assets to spread the word about cool roofs.
This blog spotlights examples of cool roofs that may inspire your own cool roof retrofit. The case studies include: a large apartment building; two triple-decker homes – one as part of a roof replacement and the other self-installed by the resident; and public school buildings. In most of these examples, cool roofs were done as a reflective coating, where white paint was applied over the existing roof structure.
Want to join the ranks of these cool roof success stories? Check out MAPC’s Cool Roof Site Suitability and Self-Assessment to determine if a cool roof is feasible and beneficial for your building or property.
Example 1: Pine Street Inn Housing Complex
The largest homeless services provider in New England, Pine Street Inn, installed a cool roof in 2021. The apartment building is located in Dorchester and features 52 single-room occupancy units. Pine Street Inn’s primary reasons for choosing a cool roof included energy savings, reducing the Urban Heat Island effect, and pairing with solar to meet Building Emissions Reduction and Disclosure Ordinance (BERDO) regulations. Rooftop solar is anticipated to be installed over the cool roof in summer of 2024.
| Cool Roof Type |
| Coating (Sherwin Williams KOOL SEAL Tundra Silicon) |
| Roof Area |
| ~11,000 SQ. FT |
| Location |
| Dorchester, Boston |
| Cost |
|
| Project Completed |
| 2021 |
| Partners |
| LISC, Resonant Energy, Lydon Roofing |
| Advice |
| “It took several days of labor to remove debris and ensure the surface was clean prior to cool roof application, but power washing was not necessary. If you have solar panels on the roof, you’ll need to coordinate with your solar developer to temporarily remove the panels while applying the coating. If you have equipment on the roof, delineate pathways on the roof to reach equipment to reduce foot traffic on the roof and avoid damaging the coating. Make sure you get the right labor for the job – you need roofers, not painters.” |
| Results & Maintenance |
| Pine Street Inn noted that the cool roof would require occasional cleaning, but that no maintenenance issues had been reported to date. Since the cool roof installation, the building has seen a moderate change in energy consumption, but it's unclear how much of this is due to the cool roof because other energy efficiency upgrades were made at the same time. Facilities managers have shared anecdotally that the cool roof has made it easier to maintain their required indoor temperature of 73°F. |
Example 2: Triple Decker - Roof Replacement
While planning to replace their roof last summer, one condo-owner of a triple decker in Jamaica Plain encouraged her neighbors to upgrade to a cool roof. The driving factor was to reduce indoor heat, particularly for 3rd floor residents. Given they were replacing their roof, the quote from the contractor and roofing specialist showed no additional costs or aesthetic differences for choosing a white membrane. The added heat-reduction benefits of a white membrane, without any extra costs, pushed the condo-owners to opt for a cool roof.
| Cool Roof Type |
| Single-ply white membrane |
| Roof Area |
| ~ 1,670 SQ. FT |
| Location |
| Jamaica Plain, Boston |
| Cost |
| No added cost for white membrane during roof replacement |
| Project Completed |
| August 2023 |
| Testimonial |
| “My neighbors were concerned that the cool roof would raise heating costs in the winter. After researching, we learned that the benefits in the summer outweigh the costs in the winter." |
| Results & Maintenance |
| Since the retrofit was completed, there have not been reports of maintenance repairs needed for the white membrane. The condo-owner noted it was too early to tell if there are any notable energy savings. |
Example 3: Triple Decker - DIY Coating
A 3rd floor resident of a triple decker building in Cambridge took matters into his own hands to beat the heat by applying a white reflective coating on his 18-year-old EPDM roof. Upon learning that a cool roof could be as simple as applying a coating of reflective paint, the resident cleaned his roof of dirt and debris, purchased a roller and silicone coating, and completed the cool roof project himself in about 6 hours.
| Cool Roof Type |
| Coating (Henry Tropi-cool silicone coating) |
| Roof Area |
| ~ 1,100 SQ. FT |
| Location |
| Cambridge, MA |
| Cost |
| $599 |
| Project Completed |
| June 2020 |
| Testimonial |
| “I live on the top (3rd) floor and do not have AC in my unit. On 90°F days, my home would reach around 5°F hotter than the highest outdoor temperature of the day. After painting the roof, the indoor temperature has been much more comfortable and has never exceeded the highest outside temperature. On a recent 95 plus degree day, the indoor temperature remained below 90°F day. Cool roofs should be required on all new and replacement flat roofs.” |
| Results & Maintenance |
| The residents have noticed a significant difference in indoor temperatures during the summer months after installing the cool roof. They did not observe a change or increase in heating costs in the winter months. Since painting the roof, the surface has yellowed slightly due to dirt. However, aside from some cleaning, the cool roof coating remains intact and not in need of any repairs or reapplications. |
Example 4: School Buildings in Chelsea
The City of Chelsea is one of the region’s hottest urban heat islands due to heavy development and minimal vegetation. When planning unrelated roof improvements for school buildings about 5 years ago, the facilites manager discovered the sealing and cooling benefits of cool roofs. The School District then embarked on a multi-phase project to apply cool roof coatings to all school buidings, including the Chelsea Early Learning Center (2018), Williams School (2020), Mary C Burke Elementary Complex (2021), and the High School (2022).
| Cool Roof Type |
| Coating (LiquiTec Fluid-Applied Membrane) |
| Roof Area |
| Multiple buildings |
| Location |
| Chelsea, MA |
| Cost |
| Not available |
| Project Completed |
| Multiple projects from 2018 to 2022 |
| Partners |
| Garland Co, SOCOTEC, Mount Vernon Group, Boston University School of Public Health |
| Testimonial |
| “Beyond the white color, LiquiTec is low-VOC and nearly odor-free, posing virtually no risk of disruption to anyone inside the building. The product applies thick and cures fast, so the projects were much shorter durations than a roof replacement allowing more buildings to be tackled in a limited time frame. Most importantly, the monolithic fluid applied system has provided superior waterproofing that has kept our schools free of leaks.” The quote is pulled from this Garland Co Article. |
| Results & Maintenance |
| The school facilities manager anecdotally shared that the temperature of the roof is now 30-40°F cooler than before, which has resulted in notably cooler temperatures indoors. In the summer of 2021, researchers at the Boston University School of Public Health measured the impact of the cool roof at Williams School compared to other areas in Chelsea with dark-colored roofs. They found that the land temperature around the school was about 4.5F lower near the school, demonstrating the heat reduction benefits of cool roofs at a neighborhood-level. As an added benefit, the roof coating added 10 years of warranty to the roofs. |