Eco homes vs changing climate

Malaysia’s climate is changing and there is a scramble to address it. Theories are being thrown around, from the usual global warming to the rise of data centres and their water consumption.

It is a broad issue, however, with Malaysians needing to learn how to cope with the uncertain future of climate and, consequently, heat management.

As temperatures rise, the current passive design strategies that once helped homes stay cool and comfortable may be obsolete now.

For years, an eco home on this side of the world had a simple task. Use less energy, reduce dependence on air conditioning, and allow natural breezes and ventilation into the house.

These were typically achieved with specialised fixtures like large roof overhangs, shaded open windows, ventilation tiles, purposeful landscaping and building orientation. Long-standing staples of sustainable design, these fixtures were efficient during their time and are still used in many homes today.

But with Malaysia’s climate becoming more erratic, it has raised a very uncomfortable question for the property industry as a whole.

Are today’s designs still properly equipped for the uncertain climate that is coming?

The Malaysian Meteorological Department (MetMalaysia) has said that long-term data, from around 1969 to 2025, shows that average surface temperatures increased roughly 0.24°C per decade. This is unique to Peninsular Malaysia, however.

In Sabah, the average temperature has risen around 0.15°C per decade while Sarawak has seen 0.14°C per decade.

The official reports also identified heatwaves as one of the increasingly frequent extreme weather events that is directly related to climate change.

Fortunately, Malaysia’s climate policy is forward-thinking and comprehensive.

Take the National Policy on Climate Change 2.0 for example. Originally drafted in 2009, it was updated and approved in late 2024. When paired with the National Carbon Market Policy, it targets ambitious goals like net-zero greenhouse gas emissions by 2050.

For housing, it is becoming more likely that sustainability can no longer be viewed solely through the lens of energy consumption alone because a house can be energy efficient but still struggle to remain comfortable during prolonged periods of extreme heat.

When hot air overwhelms

Cross ventilation, solar shading, thermal insulation and daylighting are suitable for Malaysia’s tropical climate, according to the Construction Industry Development Board (CIDB).

Traditional Malay houses in particular offer a useful lesson. Raised floors, ventilated walls, pitched roofs, generous overhangs and very carefully positioned openings were responses to the local climate rather than simply architectural decoration. Natural airflow and shading helped reduce heat build-up without the need for mechanical cooling.

Modern green homes have adapted many of these principles using contemporary materials and technology. But the catch is that passive cooling has its limits.

Cross ventilation works best when the outdoor air is able to provide useful cooling. But when the air outside is already hot and humid, opening more windows does not magically make it cooler.

Likewise, shading can prevent direct solar radiation from entering a home but it cannot lower the temperature of the hot air coming through an open window.

This makes the distinction between energy efficiency and climate resilience even more important because an energy-efficient home is designed to reduce its energy demand, yet a climate-resilient home also needs to remain liveable as temperatures and weather conditions change.

Ageing buildings

Research by GreenRE, in collaboration with Universiti Malaya, reveals that buildings aged 18 years and older consumed nearly twice as much energy as newer buildings with similar characteristics.

Researchers are looking at developing a tool to help assess their performance and identify opportunities for retrofitting. That is quite significant for a country with a large stock of existing older homes.

While a house may be designed for energy efficiency, its performance degrades over time due to ageing cooling systems, deteriorating building materials, shifting landscaping, evolving occupant habits and surrounding developments that block shade and airflow.

Interestingly, GreenRE and Universiti Teknologi Malaysia are separately developing an energy performance benchmarking tool specifically for landed residential buildings in Malaysia.

Existing energy-performance tools developed in temperate countries such as the United Kingdom, Australia and the United States are not fully applicable to tropical homes without significant adaptation, particularly because of Malaysia’s cooling requirements and passive-design considerations.

Higher electricity bills

This matters because hotter homes can create a vicious cycle.

As temperatures rise, residents turn to air-conditioning for longer periods. That increases electricity consumption which in turn makes energy efficiency even more important.

Malaysia has experienced this during the 2016 heatwave when unusually high temperatures contributed to a sharp increase in electricity usage.

Peninsular Malaysia’s peak electricity demand reached 17,788MW on April 20, 2016, up 5.2% from the previous peak of 16,901MW recorded in 2014.

Even though this example is considered a decade old, the underlying issue is still relevant because if homes become increasingly dependent on mechanical cooling, the energy savings gained through passive design can be eroded by the growing cooling demand.

A shining example

A Google search for efficient buildings in Malaysia highlights Putrajaya’s Diamond Building, a prime example of sustainable design. Its integrated passive features such as smart orientation, low-E glazing and roof insulation work alongside automated building management systems to significantly reduce heat gain.

The result is notable because the building’s current average building energy index is 65kWh/m² per year, compared with 210kWh/m² per year for a typical Malaysian office building cited by the Energy Commission.

While it is an office rather than a home, the lesson is still relevant to residential design.

Residential examples also prove this point.

A 2024 study on the Anjung Kelana residence in Port Dickson showed that passive design strategies directly improved indoor thermal comfort, underscoring the importance of evaluating actual living conditions rather than relying on a green checklist.

The lesson is that passive measures do not have to replace technology, but rather, reduce the burden placed on technology.

Reducing urban heat island effects

CIDB highlights greenery and shading to combat urban heat, citing Shah Alam’s Garden City masterplan and the Laman PKNS building which uses strategic orientation, low-E glazing, and horizontal shading to minimise heat gain. Residential homes can achieve similar results through much simpler methods.

Ultimately, Malaysia’s eco-homes need a rethink. Home buyers must look beyond superficial green labels at sales galleries and ask how much cooling a home actually requires, ensuring its design remains climate-resilient for decades to come.