From the busy streets of New York City to the quiet towns of Montana, more and more multifamily developers are beginning to embrace green building principles.

“This is the direction in which the entire housing industry – including multifamily – will be moving,” said John J. Loyer, a construction, codes, and standards specialist for the National Association of Home Builders.

For example, Missoula, Mont., is not the kind of place where one expects to encounter the latest trends sweeping the building industry. But homeWORD, an affordable housing developer in Missoula, develops all of its projects to be energy-efficient green buildings, even for small projects like the 35-unit Orchard Gardens, opening this spring.

For both market-rate and affordable housing developers, green building ideas are beginning to make great business sense.

Despite the popular perception that green buildings need lots of expensive technology like geothermal heating, green roofs or solar panels, creating a green (or high-performance) building really means building a development that uses less resources and is healthier to live in – and that typically starts with energy efficiency.

“You don’t need to drill in the ground, put plants on the roof or put up solar collectors,” said Andy Padian, senior housing specialist with Steven Winter Associates, Inc.

In fact, the average “green premium” added just 2.42% to the total development costs of constructing a green project, according to a study conducted by New Ecology, Inc. The study examined 16 green affordable housing projects, including both newly built developments and rehabilitations of older buildings. The total development costs for these projects ranged from 18% below to 9% above the costs for comparable conventional affordable housing.

For market-rate projects, the right tenants are willing to pay more to live in these healthy, efficient buildings. Only a handful of green apartment buildings have been completed, but in New York City developers have already found that their green projects rented up quickly at rents 10% to 15% above the surrounding market. Luxury apartment developers are now combing the country for other markets where tenants might pay more to live green.

Green building ideas are especially taking hold in the affordable housing industry, as local officials and funding programs have begun to champion sustainable development.

“In five years it will just seem stupid to build affordable housing that is not green anywhere,” said Bart Harvey, chairman and CEO of Enterprise Community Partners, Inc.

But green building is not just for brand new buildings. These ideas can also save money at existing projects.

In the last year, the cost of heating and lighting an apartment building has risen sharply. According to the Energy Informa-tion Administration, the average price of residential heating oil rose almost 20%, and the average price of residential natural gas rose more than 43%.

For landlords who struggled with these higher costs, there’s just a handful of months between today and the next heating season. Use that time to put some energy-efficient ideas into practice at your building: Green building experts offer suggestions that can cut your energy costs by up to a third, ranging from simple equipment replacement to full rehabilitations.

A variety of programs reward both affordable and market-rate developments for becoming more energy efficient. For a comprehensive list, visit the National Housing Trust’s Web site at www.nhtinc.org/pub_pol_green.asp.

There are also government subsidy programs that can help poorer tenants pay their heating bills. To find out if tenants at your project can receive state or federal help, visit www.acf.dhhs.gov/programs/liheap/.