Caylume Building Products said on Monday it was recalling 41,600 tins of its Sunveil roof coating from shops in Barbados, Grenada and Saint Lucia after a study found that homes treated with the paint stayed warmer at night and used more air conditioning. The company has stopped shipments and is offering refunds for unopened tins.
The research, published Monday in the Caribbean Journal of Building Physics, examined 612 homes and found that rooms beneath roofs painted with the coating averaged 1.6°C (2.9°F) warmer between 22:00 and midnight than comparable rooms without it. Researchers estimated the added electricity cost across the three islands at BDS$12 million (about €5.5 million) and EC$32 million (about €10.9 million).
The study’s night-time readings
The team tracked indoor temperatures and household electricity use for 16 months, comparing 216 homes whose roofs had been coated with 396 similar homes. Researchers adjusted their calculations for weather, building size and reported use of air conditioners. The coating was marketed as reflecting sunlight, but the study found that its surface released less heat after sunset than conventional roof paint.
Jitka Pourová, the study’s lead author at the fictional Coral Reach Institute, said the results did not mean every painted roof would produce the same effect. “The unexpected finding was not that the coating failed to reflect sunlight; it did. It was that the roof shed heat so slowly after dark,” she said.
The roof looked cooler in the afternoon, but the rooms stayed warmer after sunset.
Jitka Pourová, study lead author
The researchers estimated the extra power use at 14% on average among homes using the product. They calculated that the additional bills over three years amounted to about US$17.8 million (roughly €16.4 million) in total, using household tariffs and sales figures supplied by retailers. The estimate is not a forecast of future costs and excludes homes where the coating was used on outbuildings.
A voluntary product withdrawal
Caylume said it would pull all tins from retailers while it reviewed the study, including batches not tested by researchers. The company said the coating met its published reflectivity specifications and that it had received no reports of product damage. It disputed the study’s estimate of higher bills, saying household air-conditioning use is difficult to compare.
Efe Balcı, an energy analyst who was not involved in the research, said the proposed mechanism was physically plausible but the results needed testing beyond the three islands. “Roof colour is only one part of heat entering a home,” he said, pointing to ventilation, shade and ceiling insulation as factors that can change indoor conditions.
The Island Product Safety Commission said it had asked retailers to stop sales and display refund instructions. It has not ordered homeowners to remove the coating. The commission is reviewing the product’s advertising, which described the finish as helping roofs “cool after dark”.
Pourová said the team plans to publish its measurement data and repeat tests on homes with different roof materials. For now, the company’s withdrawal leaves homeowners who bought the paint with a choice between seeking a refund for unused tins or waiting for further guidance on roofs already coated.
