FOR China, energy conservation starts at home.

The German edition of the Financial Times reported this month that the energy consumption of China's apartment buildings makes up a third of the country's total energy needs, and is twice or triple the energy use of Western homes.

Aging, ill-designed heating system and poor insulation in Chinese houses are mainly to blame for this huge waste of energy.

This reality is becoming increasingly unacceptable, says the report, as homes with design flaws in energy efficiency bode ill for China's campaign to cut carbon emissions and meet green growth targets.

The success of this campaign hinges largely on the schemes Chinese authorities are implementing to build more green homes and upgrade those that are less environmentally-friendly.

The ministries of Finance and Housing and Urban-Rural Development released a joint circular on May 7 calling for stepped-up efforts to boost energy efficiency in urban housing.

By official estimates, the housing sector will be a major consumer of energy next to transport and industry by 2020, gobbling up more than a third of the nation's energy supply.

According to the circular, energy-efficient buildings will represent over 30 percent of all new construction by 2020. And the nation plans to expand the surface area of green housing by 1 billion square meters. Key to realizing these ambitious goals is the adoption of revolutionary environmental housing standards.

China has been endorsing ever tighter criteria for low-carbon housing since 1986, when houses were required to be built in a way that allowed them to save up to 30 percent of energy.

In 1995, the national target was lifted to 50 percent, and in some eco-savvy localities it has been further increased to 65 percent.

Statistics from the national housing authority shows that low-carbon apartments in urban China boast an aggregate size of 2.85 billion square meters, or only 16 percent of all urban buildings. The remaining 84 percent is highly carbon-intensive.

Analysts say if we count in the energy costs incurred in the building process, then the carbon intensity of housing account for a whopping 46.7 percent of the nation's overall energy consumption.

Some believe the national green housing standard - apartments that reduce carbon intensity by 50 percent - is still not audacious enough. Even if every province and municipality aims for cuts of 65 percent, China's housing will still consume 50 percent more energy than in developed countries, due to lackluster air-conditioning, heating, ventilation and lighting systems.

A few experts disagree. Li Kexin, a researcher of environmental science at Shanghai Advanced Research Institute, told Shanghai Daily that widespread enforcement of China's low-carbon housing standards began just a few years ago.

"I believe the standards will over time get more stringent. But it doesn't mean current standards on green homes are lax," said Li. He added that there is no universal standard on what constitutes a green home, as its definition is subject to myriad local variations, such as different architectural styles and population density.

What's more needed to make current standards work is a change in officials' mindset, and more importantly, management, according to Li.

A major reason tougher standards don't always bring about intended changes is that they are not strictly enforced.

According to a report by People's Daily, the Ministry of Housing and Urban-Rural Development (MHURD) dispatched a team of surveyors to southwestern Guangxi Zhuang Autonomous Region in 2008 to inspect the enforcement of green building codes. Their findings were disappointing: The locale planned to cut energy costs by 50 percent in its newly built homes, but in practice they saved only 30 percent.

It was reported that some unscrupulous property developers failed to enforce the low-carbon - and more costly - building standards. A more disturbing fact is that local supervisors were either lackadaisical or couldn't tell if corners were cut.

The lack of due oversight will make it hard to deliver on bold promises to go green, says Professor Zhu Dajian of Tongji University.

"If we push green home standards by fiat, just like how we once trumpeted GDP above all else, they won't reap good results," he said.

Zhu noted that the right approach should be that the government devises the standard, while the market decides the prices of new building materials and technologies. Of course, at the beginning of adopting greener standards, it is incumbent on the government to provide incentives, subsidies and other financial support.

Green growth

Qiu Baoxing, deputy minister of the MHURD, has said China's investment in home energy conservation projects will total at least 1.5 trillion yuan (US$237.7 billion) by 2020.

Moreover, the national fiscal authorities will reward areas that qualify as exemplary ecological zones with 50 million yuan or more.

Right now officials are eyeing the huge business potential that will be unleashed by the drive to tap the green housing industry, estimated to be worth billions. It's not entirely wrong to see green growth in monetary terms. But there are financial limitations. The renovation of less carbon-efficient homes poses a problem, for it is costly compared to erecting new homes employing green standards.

It is thus necessary to balance costs and lofty green goals, said Li, the environmental researcher. Rather than recklessly applying green building codes at whatever costs, they should be tailored to local conditions. Simple, inexpensive measures can sometimes greatly contribute to the energy efficiency of homes - such as improving insulation of walls and installing double-glazed windows.

For instance, two glass panes separated by an inert gas-filled space of 20 millimeters is 40 times as effective in reducing heat loss as a single piece of glass.

Shanghai is leading the country in cutting carbon emissions in houses, with such efforts as applying insulation to facades of buildings. But there is still a long way to go. Shanghai needs to contemplate homes' energy conservation in future urban planning so as to prevent follow-up facelifts and tinkering, said Li.

Squandered legacies

And the city may have squandered a wealth of environmental legacies, as many of the best practices showcased at the Expo were not followed up, said Zhu, the Tongji professor.

In building more low-carbon homes, we tend to look to the future. But it may help to sometimes look back and turn to our ancestors for hints.

Ruan Yisan, a professor of historical Chinese architecture at Tongji University, argued in a commentary last year that traditional Chinese architectural styles are essentially green by today's standards.

Ancient Chinese dwellings are not enclosed on all sides by walls. However, fronted invariably with a courtyard, they are well-lit and well-ventilated, thanks also to the skylight in the roof. This is something unimaginable for many modern dwellers who cannot live without air conditioners, wrote Ruan. Although it would be hard to incorporate those features in modern urban dwelling, we can at least be inspired by their inherent respect for nature.

Many of China's city managers are hardwired to build high rises with uniform looks and high energy consumption. And now with green home concepts in fashion, they are suddenly jumping on the bandwagon of a green revolution. Unless they see the incoherent logic, they will waste a lot of time, money and energy in rhapsodizing about the benefits of green architecture, but never really get their hands on it.