Many people who want to live in an ecological house think they can't afford it. They see expensive solar systems on the roof, bafflingly complex heating and hot water devices and unusual, custom architecture.

Now that ecological or "sustainable" architecture is becoming trendy, they see high price tags for the "added" sustainable features.

Despite these perceptions, there is no reason why a properly designed ecological house should cost more than a "standard" house. In fact, if the long-term operating expenses are taken into account, it could very well cost less.

To see how, we need to consider what an ecological house should do. While there are many aspects to a home's ecological performance -- the conservation or even net-positive production of energy, water, food and material goods -- we'll focus on conserving and augmenting the energy needed for heating and cooling.

We can begin by stating categorically that a house does not need to be loaded up with expensive high-tech gadgetry to conserve energy. In fact, if we consider the design work, energy and materials needed to create some of the elaborate heating and heat-recovery systems that pass for "sustainable extras" in many new homes, and compare that to the energy that such systems actually conserve, we'll find them wanting -- especially since far simpler and more effective conservation strategies are available.

Long before incorporating a high-tech mechanical system into the design of an energy efficient house, we should ensure that the building is:

n no bigger than it has to be

n properly oriented and designed with respect to the sun and prevailing weather, and

n well insulated and sealed.

Appropriate size and proper climate design are virtually free energy conservation features, as they are simply the product of good design. If anything, these fundamental features are subtracted from, rather than added to the cost of the home -- smaller houses cost less to build and houses that simultaneously take advantage of and offer protection from the local climate are cheaper to operate.

Free or low-cost adaptations to particular climates can include simple shading devices and breezeways where it's hot, and compact, enclosed buildings with storm porches (also called "sun porches") where it's cold. The same storm porches become cool spaces by opening their windows in the summer. Most houses have some kind of porch; why not spend a few extra dollars and enclose that porch and make it a climate-control feature?

Another inexpensive and easily incorporated design feature that will work for many houses is "passive solar" heating. A passive solar heating system gathers heat from the sun and stores it in a "thermal mass," typically a concrete slab floor or masonry wall. When the sun goes down, the stored heat is released into the house. It is as easy to design a passive solar house as any other kind and the costs are the same or only slightly higher than those of standard construction.

Maximizing insulation to the point of diminishing returns for energy savings and sealing air leaks is integral to all good climate design. Nothing is cheaper or easier to install than insulation and weather sealing, and nothing provides a better return on your investment. A house should be super well insulated in any climate, hot or cold, because it takes just as much energy to cool a house on an Arizona summer day as it does to heat one in the Montana winter.

The best part of building low-tech, low-cost energy conservation features into a house is that they will pay for themselves in energy-cost savings in a few short years. After their small initial cost is recouped, they will continue to conserve energy, or gather it for free from the sun, for the life of the house. They don't break down, they don't need a technician coming by, and they don't go out of date or out of style. They're not expensive add-ons -- they're integral to the design.

Can you afford to live in the new or remodeled ecological house of your dreams? If you follow nature's principle of doing the most with the least, you bet your bottom dollar you can.