Energy efficient homes mean less air pollution. But are they affordable?

Inspired by the Dutch concept of “Energiesprong,” or “energy jump,” a developer in France retrofitted a group of townhouses for social housing to be more environmentally friendly. They installed polyurethane facades to avoid heat loss and solar panels on the roof. Upgrading the units to be more green cost more than a conventional retrofit, but over time, energy bills were cut in half. These green retrofits are being implemented in towns around the world and could be a model for developers that want to reduce their carbon footprints.

Apartments at Front Flats, a new residential building in Philadelphia, is powered by 492 solar panels that are wrapped around the building. The point: to demonstrate that developers can design buildings that are energy-efficient and be built at an affordable cost. It’s not clear yet if the building is “net zero” in terms of producing as much energy as it consumes, but residents are paying only $40 a month for utilities.

A housing project in Brooklyn is taking nine apartment buildings and retrofitting them to be more sustainable and cut carbon emissions. Casa Pasiva is a $20 million project that aims to reduce heating and cooling costs because of updated machinery and thick exteriors that will improve air quality. Funding for these types of initiatives is not always certain, but a collaboration between a developer and a nonprofit, with some city financing, made this first-of-a-kind green building renovation in New York possible.

Across Salt Lake City, Utah, housing developers are building more net zero energy homes. Facing air quality issues, the state has yet to set more energy efficient codes for new homes, which means the kind of homes being built by developers like Redfish, Garbett Homes, and Ivory Homes, are being constructed on a much smaller scale. Such homes, while costing 2-5% more to build, have shown to decrease energy costs by 50-60%.

Twenty-first century cities face the factors of climate change with intensity as urban heating threatens human and the earth’s health. The University of Notre Dame has conducted research on green and cool roofing projects in the city of Chicago. They have found that green and cool roofs help mitigate the heat in cities; however, these roofs should be installed with other strategies like ponds and trees.

An apartment complex in Utah includes a solar battery in every apartment allowing the resident, power utility, and building developer to save costs for generating electricity. Through a unique partnership, the power systems can provide 12.6 megawatts of power for the building, which translates into residents saving up to 40 percent on the energy bills. This setup might not be easy to scale, but the developer plans to expand the model in other states.

More and more commercial real estate projects are popping up around the United States that are focused on “deep green” building. This movement suggests that it’s not enough to just make a building out of renewable materials, but they can also be self-sustaining. For example, the Watershed, an office building in Seattle, has a slanted roof that collects rainwater that is then used in toilets. These types of projects can be more complicated and expensive to build, but developers can save money in the long run with the improvements.

An architect in Chennai, India, is retrofitting private residences and public buildings to be more sustainable. They make changes like installing energy-efficient upgrades, solar panels, improved ventilation, and low-flow plumbing fixtures to reduce water and energy consumption.

In Brazil, the world's largest producer of sugar cane, industry leaders have found a way to harvest the crop without sugar cane burning. Sugar cane burning is harmful to the environment and nearby residents. After complaints and regulations, producers invested in technology that allows them to cut the cane without burning it. This is a contrast to South Florida, despite producing less sugar cane than Brazil, producers in the state continue the practice.

In Cambodia 2.5 million people use stoves fueled by forest biomass; charcoal and wood. The emissions caused by using biomass are extremely harmful not only to people but also to the environment. The emissions caused by biomass globally are equal to those of the aviation industry. To counter the problem, several organizations and companies are providing alternatives for Cambodian families like electric stoves. One company, Khmer Green Charcoal, created stoves that run on “clean” charcoal made from coconut shells. More than 6,500 households across the country have made the transition.