S$60 Million Reflective Paint Rollout Across All HDB Estates

Singapore's Housing and Development Board (HDB) has committed to applying heat-reflective paint across every public housing estate in the country by 2030. The budget: S$60 million under the Green Towns Programme. The goal: measurably reduce ambient air temperatures in the densest residential corridors of the city-state.

What Happened in Tampines

The programme began with a pilot in Tampines, launched in October 2022. Workers applied a specialised coating containing additives that reflect solar radiation across building facades and rooftops. After several months of monitoring, the results showed ambient temperatures near treated buildings had dropped by up to 2 degrees Celsius. Residents in the affected blocks also reported lower air-conditioning usage, which translated into measurable reductions in electricity bills.

The paint works by reflecting near-infrared radiation — the portion of sunlight responsible for heat transfer. Standard building paints absorb this energy and re-emit it into the surrounding air. Reflective formulations redirect a significant portion of it back toward the atmosphere before it can heat the building surface or the air around it.

Passive Radiative Cooling: Next-Generation Formulations

Beyond the HDB programme, researchers at Nanyang Technological University (NTU) and other Singapore-based institutions have developed a new class of passive radiative cooling paint. These coatings combine two mechanisms: high solar reflectance (88–92%) and strong thermal emission through the atmospheric window (around 95% emittance in the 8–13 micrometre range).

In practical terms, this means the paint can cool a surface to 3°C below the ambient air temperature without any energy input. Field tests conducted in Singapore's tropical climate confirmed superior performance compared to conventional white paints, even in humid conditions where radiative cooling typically loses effectiveness.

A key innovation is the use of barium sulphate pigment particles at specific size distributions. Earlier cool paints relied on titanium dioxide, which absorbs UV radiation and re-emits some of it as heat. Barium sulphate does not have this limitation, allowing higher net reflectance across the full solar spectrum.

Durability Under Tropical Rain

One concern with advanced coatings is degradation under monsoon conditions. The NTU formulation addresses this through a modified cementitious binder that retains approximately 30% of its weight in water. This retained moisture contributes an additional evaporative cooling effect during dry periods. The optical performance remains stable when the surface is wet, unlike many commercial alternatives that lose reflectivity under moisture.

How Cool Materials Fit into Singapore's Broader Strategy

Cool coatings are one component of a multi-layered approach coordinated through the Ministry of Sustainability and the Environment. According to government data, applying cool materials to building exteriors can reduce surrounding air temperatures by up to 1.6°C and wall surface temperatures by up to 5.6°C.

JTC Corporation, which manages Singapore's industrial estates, has piloted cool paint on warehouse and factory rooftops. The rationale is straightforward: industrial buildings have large, flat roof areas that absorb substantial solar energy. Treating these surfaces can reduce cooling loads for both the buildings themselves and the surrounding neighbourhoods.

These material-based interventions are complemented by vegetation programmes, centralised cooling systems, and urban design guidelines that promote natural ventilation through building orientation and spacing.

Scale and Cost Considerations

The S$60 million allocated covers paint, application labour, scaffolding, and maintenance for reapplication cycles. Heat-reflective paint typically requires recoating every 5–7 years, depending on exposure and rainfall intensity. For a country with over one million HDB flats, the logistics involve coordinating work across more than 10,000 residential blocks in various stages of their maintenance cycle.

An independent assessment published by the Building and Construction Authority (BCA) noted that the cost per square metre of reflective coating is 15–25% higher than standard exterior paint. However, when factoring in reduced air-conditioning energy consumption — estimated at 2–5% per treated building — the payback period falls within 3–5 years for most building types.