<p>Think solar houses are clunky and unattractive? Check out these spiffy solar houses. They are designed and built by college students for the &#34;Solar Decathlon&#34; sponsored by the US Department of Energy. Yes, they&#39;re small, but they are 100% powered by renewable sources.</p><ul><li><a href="https://www.thoughtco.com/solar-house-designs-from-decathlon-178405" data-component="link" data-source="inlineLink" data-type="internalLink" data-ordinal="1">2015 Solar Decathlon Homes &gt;</a></li></ul>If you live in a traditional or historic home, you&#39;ll probably hesitate to add high-tech photovoltaic solar panels. But some older homes can be converted to solar without harming their architectural charm. Plus, converting to solar can be surprisingly affordable, thanks to tax rebates and other cost-cutting incentives. Check out the solar installation at the historic Spring Lake Inn in Spring Lake, New Jersey.<p>You might not find one in a traditional neighborhood, but oddly-shaped geodesic domes are among the most energy-efficient, most durable houses you can build. Made with corrugated metal or fiberglass, <a href="https://www.thoughtco.com/what-is-a-geodesic-dome-177713" data-inlink="5R6i4-jZEZNrpDWpm7dQiw&#61;&#61;" data-component="link" data-source="inlineLink" data-type="internalLink" data-ordinal="1">geodesic domes</a> are so inexpensive that they are used for emergency housing in impovershed countries. And yet, geodesic domes have been adapted to create trendy homes for affluent families.</p>If there is anything stronger than a Geodesic Dome, it would have to be a <em>Monolithic</em> Dome. Constructed of concrete and steel rebar, Monolithic Domes can survive tornadoes, hurricanes, earthquakes, fire, and insects. What&#39;s more, the thermal mass of their concrete walls makes Monolithic Domes especially energy-efficient.<p>Not all modular homes are energy-efficient, but if you choose carefully, you can purchase a factory-made home that is fine-tuned to minimize power consumption. For example, <a href="https://www.thoughtco.com/house-style-guide-american-home-4065233" data-component="link" data-source="inlineLink" data-type="internalLink" data-ordinal="1">Katrina Cottages</a> are well-insulated and come complete with Energy Star rated appliances. Plus, using pre-cut factory-made parts reduces environmental impact during the construction process.</p><p>Let&#39;s face it. Do we really need all the rooms we have? More and more people are scaling down from energy-hogging <a href="https://www.thoughtco.com/what-kind-of-house-mcmansion-178015" data-component="link" data-source="inlineLink" data-type="internalLink" data-ordinal="1">McMansions</a> and choosing compact, comfortable houses that are less expensive to heat and cool.</p>Homes made from earth have provided inexpensive, durable, eco-friendly shelter since ancient times. After all, dirt is free and will provide easy, natural insulation. What does an earth house look like? The sky&#39;s the limit.<p>The most energy-efficient houses function like living things. They are designed to capitalize on the local environment and to respond to the climate. Made from simple materials found locally, these homes blend into the landscape. Ventilation systems open and close like petals and leaves, minimizing the need for air conditioning. For examples of life-like earth-friendly homes, look at the work of Pritzker Prize-winning Australian architect <a href="https://www.thoughtco.com/glenn-murcutt-master-architect-environment-177863" data-inlink="HFWfA0gcuyhyT4DFVGVzWQ&#61;&#61;" data-component="link" data-source="inlineLink" data-type="internalLink" data-ordinal="1">Glenn Murcutt</a>.</p>You don&#39;t have to build a whole new house to reduce your impact on the environment. Adding insulation, repairing windows, and even hanging thermal drapes can yield surprising savings. Even changing lightbulbs and replacing showerheads will help. But, as you remodel, be mindful of indoor air quality. Consider using eco-friendly paints and cleaning agents.