Hi, Elain. I am a full time realtor in Rapid City, SD, nationally certified to assist persons with energy and environmental real estate issues. And, as a Ph.D. engineer and physicist, with a long-time interest in home energy management, I know there are a surprising number of practical sources for your answers. So I will try to provide you with some get-started reading. There are even more reference citations on my web site http://www.BlackHillsMarketWatch.com.

You have asked about five very good questions that are also on the minds of many other home buyers and sellers:
1. What green mod's are most eco-friendly?
2. What are the best ways to preserve water and energy resources?
3. What green mod's improve a home's value most?
4. What home mod's save the most on utility bills?
5. What do we and other buyers seek the most, when buying a home?

A truly thorough and actionable response to all your questions would fill a book on green real estate. But the short answers to your questions are:

1. Eco-friendly Mods?
HVAC systems that reduce energy consumption, using low-VOC products and practices, enhance attic and other insulation, install higher efficiency windows and hot water heater, grow deciduous trees that shade the home in summer but not winter, run a whole-house fan instead of a/c, drought tolerant landscaping, exterior caulking, window shading (e.g., awnings), use of remod building materials that pull a low-carbon footprint. There are quite a number of energy-savings calculators, self-assessment checklists, and good-practice guidelines from the Federal Dept of Energy, EPA, National Association of Home Builders, et al.

2. Preserving Water Resources:
If not prohibitive, shunt 'gray water' to watering landscape, collect roof/gutter runoff in closed cisterns for plant watering, xeriscape landscaping, low-flush toilets, low-flow shower nozzles,

3. Green mod's that enhance home value most:
Unfortunately, the answer is "too few." Home "value" is affected by (1) public opinion, (2) appraisers' knowledge and diligence, and (3) mortgage-lenders' policies. In some parts of the U.S., e.g., upper midwest and the Northwest, eco-conscience is common. But in the northern plains states, it apears there is often far less public priority for energy and environment. The appraisers I have talked with tend to be quite conservative in incorporating energy-saving upgrades. Appraisers consider replacement-cost models and comparable-prices models. But because many home buyers are simply too simplistic to incorporate the Present Value of a future 'annuity' of reduced utilities, the appraisers must acknowledge that. Mortgage lenders who depend on the national mortgage underwriting industry, and large corporate policies simply must respect the opinions of appraisers.

Frankly, too, I am seeing too much "greenwashing" by some home builders and retrofit vendors, in claims of payoffs. Small single-family home wind turbins, particularly in areas where the National Wind Maps show marginal winds, can take longer to payoff than the life expectancy of the turbine (according to a major wind turbine vendor I talked with recently). (For more about green-washing see http://www.BHhomes.INFO.)

4. How to save on utility bills
See responses 1-2 above.

5. What do buyers seek?
That depends on which buyers you are dealing with. Buyers of homes generally seek energy/water conservation homes for one of five reasons:
a. It's cool, i.e., bragging rights
b. Gadget geeks (like we engineers....)
c. Utility cost savings.
d. "Eco-conscience"
e. The buyers are misguided, or were duped by bogus green-wash claims.

Some buyers are swooned by "dual fuel" homes (i.e., electricity and wind turbin...as if solar is written off). Some buyers simply want utility cost savings, and simply buy high-efficiency appliances. Some are convinced that Indoor Air Quality is a key to their home-satisfaction so they buy air filters, seal the home, remove VOC-products, fight radon, carbon monoxide, etc. In our Black Hills market in western South Dakota, there is very little pattern to consumer demand for real, legitimate green living. Each buyer is different. For the more superficial approaches, back yard wind turbins and high-efficiency appliances-only strategies are examples of for-show tactics.

If you want more information, the web site http://www.BHhomes.INFO has a section on Green Buildings.

I do hope some of this helps.
-Lee Alley, Ph.D., EcoBroker
Prudential Real Estate
Rapid City, SD

I've seen a lot of people mention:

1) Energy efficient appliances
2) proper insulation
3) sealing leaks

The later of the 2 are minor things that shouldn't cost too much and will save you quite a bit.