Mass-market green living: Net-zero homes

The high cost of building such energy-efficient homes has deterred many property builders and individual home owners in the past, making “net-zero” building a niche market, but that seems to be changing.

“Net-zero homes are going mainstream,” writes Kris Hudson in a Wall Street Journal article, Builders’ New Power Play: Net Zero Homes. As the title suggests, builders are spearheading efforts to change public perception of energy-efficient homes, from a “niche product for the affluent who can afford custom homes” to one the average home buyer would consider investing in.

The National Association of Home Builders took the initiative in the United States with a display home featured at their International Builders Show in Las Vegas. The home was built by the trade organisation in collaboration with Blue Heron Design/Build LLC in an effort to raise awareness of the opportunities net-zero homes can offer builders.

Although the New American Home is expected to be listed for US$2.5 million, Blue Heron says it can build similar, equally efficient but smaller “net-zero electricity homes for about $700,000”.

The article goes on to outline some of the features of a net zero home, including:

• A rooftop solar system to reduce dependency on grid electricity and potentially receive credit for excess electricity generated by the system
• Spray-on foam insulation to reduce heat transfer and reduce unwanted air infiltration
• Energy-efficient doors, windows, lighting and appliances
• High-performance heating and ventilation systems

However, not all builders agree that net zero homes are currently viable for the mass market. While cost can be a factor in the United States, Southeast Asia's tropical climate presents other challenges; heat and humidity require different solutions to extremes of heat and cold like you find in the American southwest.

Air-conditioning alone is not an environmentally sustainable solution because of the enormous amount of greenhouse gases required to run air-conditioning units, especially in a large home.

A properly cross-ventilated home can reduce the need for air-conditioning usage. This, combined with shading devices to prevent heat transference, can significantly reduce dependence on air conditioning. When air conditioning is needed, solar power can also be used as an alternative energy source.

Net-Zero Living in Malaysia

Malaysia has achieved much in the green building landscape so far, as seen in the example of Pusat Tenaga Malaysia (one of the world’s first net-zero office buildings) and the Diamond Building (Winning of the ASEAN energy award in 2012).

Although net-zero residential developments are progressing relatively slowly in Malaysia, one interesting project is Shelter@Rainforest, a self-sustainable, zero-energy longhouse built as a family home in Sabah, Malaysia.

The home includes a rooftop photovoltaic system and biogas units to provide energy for the running of the home, while rainwater collection units collects rainwater that is stored in cisterns which allows for basic water-related household functions.

A large overhanging shade roof helps keep the home 8-10 degrees Celcius cooler than the outside environment, and natural ventilation is encouraged through sliding doors with slats.

Government efforts to encourage net-zero building in Malaysia

The Malaysian government is also doing its part to encourage net-zero living. The Sustainable Energy Development Authority ( SEDA) has approved over 2,700 applications for the Feed-in Tariff (FiT) since its introduction in 2011.

Also called the Clean Energy Cash Back scheme, the FiT scheme allows homeowners who install solar-power systems to receive money for energy generated by their solar-photovoltaic systems.

From North America to Southeast Asia, the world is growing increasingly aware of the vital importance of finding a solution to global warming. Net-zero homes can be a part of that solution.