It wasn't so long ago that "green building" for some people meant living in a treetop, or building a straw bale house. But building green is much more than simply the materials used to create a home.

It's more about living gently: reducing, reusing and recycling wherever possible when it comes to materials, water conservation, energy conservation and ensuring that our indoor air quality is at healthy levels - in a house that's designed well.

A green house is about much more than whether or not there's a tankless water heater. It's about living in a place where, ideally, residents can walk to services (and therefore save gas and natural resources) and designing a home so that its western exposure doesn't cause electric bills to skyrocket because of the excess heat that's pounding the house.

"No matter what you buy or consume, there's usually an environmentally friendly way to do anything" says Julie Evans, ASID, an Austin interior designer and owner of Julie Evans Interiors.

Awareness is key

Often, simply being aware is enough to spur homeowners and consumers to seek out alternatives. For example, choosing to purchase a smaller house that doesn't require as much maintenance, or as much money to heat, cool, irrigate and otherwise keep running. It seems to be a nationwide trend, too.

The National Association of Home Builders (NAHB) recently surveyed 500 architects, designers, manufacturers and other experts to find out the top home and design trends in 2015 - and one was that the average home will shrink in size.

For example, new single-family homes built nationwide during the first three quarters of last year averaged 2,459 square feet. The NAHB study found that home size would average in the 2,300 to 2,500-square foot range by 2015. That might not seem like much of a drop, but it's the first drop of any kind in more than 30 years.

Reality means simpler living

Why? Take a look at land costs, especially here in Austin. Finding a home site that's reasonably priced in most of Austin proper has become increasingly challenging. In fact, property in Central Austin is considered so valuable that land costs almost always exceed the value of any improvements made to a house.

According to the Real Estate Center at Texas A&M University, there's a huge demand for land across the state that will likely cause prices to keep going up. The median price of an acre of Texas land was $1,681 in the first half of 2006 - 18 percent more than the median price of that same acre in 2005 ($1,423).

Add to that the demand for building materials in parts of the world that are experiencing tremendous growth (like China), plus rebuilding efforts after natural disasters like Hurricane Katrina and it's easy to see why buying or building a home has become a more expensive proposition.

"The high cost of housing has forced consumers to start making trade-offs and higher quality is trumping additional space," said Gopal Ahluwalia, NAHB's vice president for research, at the International Builders' Show in February.

Gentle design choices that look great

Low-stress design choices are another option. For example, hard surface floors have been shown to reduce allergens and improve indoor air quality - and many surfaces are on par, pricewise, with medium-grade carpet. They also look great, which only adds to their appeal.

"One of the cardinal rules of green design is durability and low maintenance," says Julie Evans. "If something lasts, it's off your mind and you don't have to stress about it."

Even better, major manufacturers in all areas of home, design and construction are coming out with products that bring green squarely into the mainstream - largely because consumers are demanding it.

Consider ultra-high-efficiency air conditioning systems, carpet made from recycled corn husks and recycled plastic water bottles (it's cooler than you think), bamboo, wood or concrete floors, Energy Star lighting and appliances, ultra-low-flow toilets and low-VOC (volatile organic compound) paints that improve indoor quality. These are just a few of the options for today's homeowners.

In the end, green living is about good design that saves time, energy, labor and materials.

Side Bar:

Tips to "Green" an Existing Home

According to the City of Austin Green Building Program, there's a lot homeowners can do to make an existing home more environmentally-friendly:

If you're remodeling, choose lumber that is certified sustainable (from a sustainably-managed forest). Most home improvement stores carry it; just ask. Hire local contractors when possible to support the local economy.

Replace standard toilets with those that use less water (just 1.6 gallons for the ultra-low-flow models) and buy water-efficient shower heads.

Decorate your landscape with plants that don't need much water. There's a lot out there, especially for Texas' unpredictable climate.

Replace incandescent bulbs with compact fluorescents for about a 40 percent annual return on investment. Worried about the color? These have also come a long way - from eerie-yellowish to the white of a traditional bulb.

Upgrade to a high-efficiency air conditioning unit and buy filters for it to help decrease allergens and improve indoor air quality.