When Peter Lytle decided to remodel a home and turn it into an example of sustainable design, he didn't mess around. 

In 2007, the executive director and founder of the Minnesota-based Live Green, Live Smart Institute found a seasonally challenged 1948 ranch house in Minnetonka, Minnesota. Then, with his organization, he employed 248 researchers, scientists, and design experts to figure out how best to turn it into an energy-efficient abode. About $2 million later, what became known as the Sustainable House earned a platinum rating for a remodel by the U.S. Green Building Council's Leadership in Energy and Environmental Design (LEED). 

It also won an award for being the highest-rated LEED home. In the course of this otherwise high-cost project, Lytle identified easy -- and affordable -- steps that would benefit smaller-scale efforts. With these tips, you won't need a major renovation or a fleet of experts to green your dwelling.

Conserve Hot Water
Save energy by turning the thermostat on your water heater down 5 degrees. Then install an AirTap from AirGenerate (airgenerate.com). It's a device that conserves large amounts of energy by drawing heat from the ambient air to warm your water.
Cost: $699
Savings: Reduces water-heating bills by up to 50 percent.

Plug Up Leaks
Keep warmed or cooled air from escaping the home by filling in small holes with nontoxic spray foam. Choose ones with no urea-based formaldehyde, such as Great Stuff Pro from Dow Building Solutions (building.dow.com). Check for holes around wiring and pipes, and where the foundation meets a wall. Avoid electrical boxes, stoves, and furnaces, and be sure not to seal windows shut.
Cost: Less than $100
Savings: Foam pays for itself in a single heating or cooling season.

Opt for a Dual-Flush Toilet
Already prevalent in many foreign countries, a dual-flush toilet drastically cuts down on water use. Whereas conventional models consume 3.5 to 7 gallons of water per flush, these more efficient versions use either 0.8 to 0.9 gallons (plenty for fluids) or 1.25 to 1.6 gallons (for solid waste).
Cost: $150 to $700 per toilet
Savings: Upgrading could save more than $100 per year on water bills.

Clean and Seal Your Ducts
If your home features a heating-and-cooling duct system, have it cleaned and then sprayed internally with a nontoxic polymer to seal leaks. Untreated duct systems typically waste 25 to 40 percent of the energy emitted by your furnace or air conditioner.
Cost: $500 to $1,200, depending on the size of your duct system and the extent of services you need.
Savings: Reduces heating and cooling bills by up to 20 percent.

Insulate Your Foundation
To prevent winter's cold weather from turning your concrete foundation into 40 tons of refrigeration, Lytle suggests taking on the sizable project of adding a 2-inch layer of Styrofoam 4 feet below ground around the house. (Be sure the local utilities mark the gas and electric lines coming into your house before you dig.) Styrofoam, you ask? It makes sense because it's a stable, inert product that doesn't leach chemicals underground (it breaks down only when exposed to UV light or certain bacteria).
Cost: $700 if you do it yourself (on a 2,000-square-foot home), or about $1,050 with outside help.
Savings: Reduces heating costs by as much as 20 percent.

Get an Energy Audit
Analyzing everything from your basement to attic, an energy audit pinpoints where you're losing energy and how to make a home much more efficient. Because the auditor can prioritize what changes offer the highest payback, following the suggestions can save serious money and energy.
Cost: $100 or less (or even free) for a basic audit from your utility company, or $200 to $800 for a more comprehensive audit with a private consultant (on a single-family home).
Savings: Implementing the changes after an audit could save anywhere from 10 to 40 percent annually on energy bills, depending on how efficient your home is to start.

Replace Metal Blinds
In a hot climate, heat builds up between metal blinds and the window, turning the blinds into a radiator, Lytle says. In winter, the same thing happens with cold air. Cellular or honeycomb shades made of fabric provide a layer of insulation.
Cost: $50 to $200 per shade.
Savings: Cuts heating and cooling expenses for an average 2,000-square-foot house by 10 to 15 percent.

Prices quoted in Spring 2009.