The 2015 Paris Climate Conference, also known as COP 21, was a big, news-making event, with the world’s attention mostly focused on global leaders’ plans to reduce greenhouse gas emissions and the use of fossil fuels. But for the first time in the UNFCC’s conference history, green building had its day at the conference, too.

Why talk about buildings at a conference about climate change? According to the United Nations Environment Programme (UNEP), buildings are responsible for more than 30% of greenhouse gas emissions, and if growth continues unchecked, emissions could double by 2050. The buildings sector has to reduce emissions by eighty-four gigatons, the emissions equivalent of 22,000 coal powered plants, by the year 2050 to do it’s part to keep the earth from warming to two degrees Celsius.

The buildings sector also offers one of the most cost-effective ways to reduce energy use and emissions, and many paths to success already exist but need to be refined or implemented on a larger scale. This makes green building one of the best ways for countries to achieve their Intended Nationally Determined Contributions (INDC’s), and forty countries have already specifically cited green building as one of the ways they can meet their INDC’s. Buildings also last a long time, and a new construction project will become the housing stock of the future. Building environmentally unfriendly today locks in problematic housing for tomorrow.

As part of the conference, the US Green Building Council (USGBC) announced that it plans to scale up to support the certification of more than five billion square feet of green building over the next five years with LEED and EDGE (Excellence in Design for Greater Efficiencies), a green building certification program for developing countries. The USGBC also committed to expanding worldwide educational resources for green building and to double non-English offerings.

All seventy-four national Green Building Councils support the commitment to achieve Net Zero carbon building and energy-efficient refurbishment of existing housing stock by 2050. Twenty-five Green Building councils made the commitment to register, renovate, or certify 1.25 billion square meters of green building by 2020. And three national green building councils made the commitment to introduce Net Zero certification.

With the construction of every new building comes a big pile of construction and demolition waste. On an annual basis, the construction and demolition industry creates more waste than any other industry in the United States. The average new construction project creates 3.9 pounds of waste per square foot, and the average demolition project creates 155 pounds of waste per square foot. Construction and demolition waste is a major environmental concern, but fortunately, construction professionals have a wide range of strategies to eliminate, reduce, and reuse construction and demolition debris, helping the environment and hopefully saving some money along the way.

Most construction waste ends up in landfills, but an increasing amount of construction waste is being removed from the waste stream in a process called diversion. Diverted materials are sorted for recycling and reuse. Metal, cardboard, paper, plastics, carpeting, and many other materials can be recycled and reused, often to the builder’s financial benefit.

As with any waste-related problem, the first step is simply to create less waste. Moving away from temporary support systems and structures as much as possible is an incredibly important way to eliminate waste in the construction process, as these temporary supports usually cannot be salvaged and get thrown away at the end of a project. For example, a modular metal form system used during concrete construction can be easily unmounted and reused for another project, avoiding wood waste from the use of plywood and lumber formwork.

While most construction waste cannot be completely eliminated, it can be reduced in both the planning and construction phases. For example, designing a building to fit standard material sizes helps reduce material waste. Builders can work with material suppliers to select material that uses minimal packaging, or even set-up an agreement to buy back any unused materials. On the job, construction professionals can choose to salvage materials from demolition projects, limit the use of adhesives wherever possible, and chip branches and trees cleared from the site for use as mulch.

Deconstruction provides a greener alternative to demolition. Selective deconstruction, also known as soft-stripping, involves going into a building before demolition and removing high-value materials such as lighting fixtures, hardwood flooring, and solid interior doors. Whole house deconstruction includes soft-stripping but goes a step further in salvaging the materials that make up the structure of the building itself, such as bricks and framing lumber. Deconstruction requires more labor and may take longer to complete than demolition, but due to the fact that most deconstruction is run by non-profits, the tax-deductible value of the donated materials can make deconstruction cost-competitive with demolition.

A team at the University of Nottingham has developed an innovative test to measure the airtightness of buildings. The PULSE test determines the infiltration rate of cold air and the loss of heated air through gaps and cracks in a building, making it possible to create targeted strategies for eliminating drafts which in turn leads to greater energy efficiency and reduced heating bills. The PULSE test also illustrates when a building is too airtight, as too little ventilation can lead to poor indoor air quality.

The PULSE test has been in development at the University of Nottingham for fourteen years and is now being commercialized as a more accurate and convenient alternative to the industry standard “blower door” technique. The PULSE test creates a low-pressure pulse throughout an entire building by releasing a short burst of air. The test takes a few seconds and creates minimal disruption for building occupants and construction workers. The PULSE test is also quick and easy enough for construction workers to perform several times before a building is complete.

In contrast, the “blower door” test takes fifteen to thirty minutes and is usually only used at the completion stage, making it difficult to implement any significant change based on the results of the test.

In a blower door test, a powerful fan mounted into the frame of an exterior door pulls air out of a building. This temporarily lowers the air pressure inside, leading to higher outside air pressure flowing in through all unsealed cracks and openings.

The blower door originated as a research tool in the early 1970’s, simultaneously invented by two groups independently studying the contribution of air leakage to heat loss in residential buildings. The first commercial blower door unit hit the market in 1980.

Regardless of which test is used, determining the airtightness of a building is a crucial step in any energy audit. For homeowners without access to professional equipment, it is possible to at least find leaks, if not measure them, by using a powerful box fan or even a fog machine.

The solar power industry in Nevada experienced something of a rollercoaster this past December. The federal government, despite fears to the contrary, maintained the federal solar investment tax credit at 30 percent. Yet despite this vote of confidence in solar power from the federal government, the federal tax credit did not solve the regulatory battle over residential rooftop solar in the state of Nevada.

Rooftop solar has been growing rapidly across the US, but particularly in Nevada, due to favorable geographical (lots of sun) and economic (favorable net metering policies) conditions. Nevada stood out as a particularly bright spot in a recent study of rooftop solar installations, with the number of installations quadrupling in Q2 of 2015. A 2014 state report found that net metering would save the state utilities 36 million dollars, and that Nevada solar users were, if anything, under compensated for the energy they returned to the grid.

And yet, Nevada recently made it much more expensive to be a residential rooftop solar power consumer. The Public Utilities Commission (PUC) raised the monthly charge for solar users from $12.75 a month to $17.90/month, with subsequent increases every three years for the next twelve years. The PUC also approved a two cent reduction in net-metering compensation, effectively requiring Nevada solar power users to put more money into the system and get less out of it.

Solar energy companies are fleeing the state. Immediately after the PUC’s decision, Solar City announced that they would completely cease operations in the state of Nevada, and a few weeks later, announced that they would eliminate 550 jobs, although some employees might get transferred to “business-friendly” states. Vivint and Sunrun are also leaving the state.

All of this, happening in a sunny state with incredible potential for solar energy, begs the question: why? A large utility in Arizona, another state with significant potential for solar power, is seeking permission to hike rates and reduce net metering credits. Across the country, utilities are fighting a coordinated battle against solar power.

The utilities are threatened, but going after solar is shortsighted. Instead of choosing to integrate renewable energy into the grid, Nevada Power and other utilities are choosing a path that makes it more cost effective for consumers to generate their own energy or at least fulfill most of their household energy needs through “behind the meter” resources, increasing costs for everyone on the grid. The utility rates are going up, but solar power and battery systems are getting cheaper.

Renewable energy, and rooftop solar in particular, is putting pressure on utilities. It is absolutely true that rooftop solar threatens the current business model, but the energy business is changing. Fighting against innovation isn’t going to help anyone.

There is no doubt that, in the green building industry, LEED sets the standard, but with the emergence of WELL, LEED is not the only four-letter certification available to green builders. The WELL Building Standard (WELL) is a performance-based system for measuring a building’s impact on human health and well-being. WELL is the first certification of its kind to focus entirely on the health and wellness of building occupants. Like LEED, there are different levels of WELL certification: Silver, Gold, and Platinum.

WELL sets performance requirements in seven categories relevant to occupant health:

Air: Poor air quality can lead to asthma, allergies, and other upper respiratory illnesses, as well as Sick Building Syndrome (SBS), which is often characterized by headache and fatigue. WELL provides strategies to limit pollutant and contaminant concentrations. This is an area of significant overlap with LEED, which sets high standards for ventilation and indoor air quality.

Water: Clean drinking water is extremely important for human health. Over-reliance on bottled water is definitely bad for the environment, and most likely bad for human health. WELL mandates proper filtration technique and regular testing.

Nourishment: WELL provides design strategies to promote access to healthy food and to empower occupants to make healthy food choices.

Light: The circadian system regulates the physiological processes that control sleep, alertness, and digestion, and indoor lighting can have an extremely disruptive effect on the circadian system. WELL promotes indoor lighting that facilitates vision with minimal disruption to the circadian system.

Fitness: Lack of physical activity is a significant threat to human health, and WELL looks at factors in the built environment that encourage physical activity such as stair accessibility, neighborhood walkability, and another notable overlap with LEED, access to mass transit.

Comfort: WELL seeks to eliminate stressful distractions such as noise and olfactory pollution, while promoting acoustic, ergonomic, and thermal comfort to prevent stress and injury.

Mind: WELL promotes design strategies and workplace policies that contribute to occupants’ good mental health, from opportunities for altruism to providing a beautiful, pleasing environment.

WELL assesses the benefit of each WELL feature on the cardiovascular, digestive, endocrine, immune, integumentary, muscular, nervous, reproductive, respiratory, skeletal, and urinary systems. For example, stress, unhealthy diets, a lack of exercise and environmental pollutants can negatively affect cardiovascular health. Comfort features, such as sound-masking and optimal ergonomics, help reduce stress. Healthy diets, exercise, and elimination of environmental air pollutants also benefit cardiovascular health.

The Green Business Certification Organization (GBCI) provides third-party certification for both LEED and the WELL building standard, a collaboration between the Well Institute and GBCI to streamline the overlap between WELL and LEED and to further develop the connection between human health and wellness and sustainable design.

The California Energy Commission (CEC) updates the Building Energy Efficiency Standards every three years, and 2016 is such a year, with all changes going into effect January 1, 2017. These standards are designed to achieve energy efficiency and improve indoor and outdoor air quality. The Building Energy Efficiency Standards cover new construction and construction on existing commercial and residential buildings in the state except for hospitals, nursing homes, and correctional facilities.

These code updates are required by law and driven by new green building technologies and materials that continue to raise the bar for energy efficiency. The CEC updates and implements the building codes, which are then enforced by local city and county agencies. These standards must be cost-effective for homeowners in the long-term, and not just provide short-term energy savings. California is a huge, geographically diverse state, and the CEC recognizes that what is cost-effective in San Diego may not be in the Central Valley. The CEC divides California into sixteen climate zones, and the standards vary from zone to zone.

The updated standards will make it roughly $2,700 more expensive to build a new home, but these upfront costs are projected to generate an average of $7,400 in energy and maintenance costs over a thirty-year period. Compared to those built to the 2013 standards, single-family homes built to the 2016 standards will use 28% less energy.

The updated standards will not get California to it’s ultimate zero net energy goals, but it will bring the state significantly closer. In 2007, the CEC and Public Utilities Commission (PUC) publicly committed to the goal that all new residential construction will be zero net energy by 2020, and all new commercial construction will be zero net energy by 2030. The 2019 building standards, then, should be the final step in achieving zero net energy for residential construction in California.

The CEC’s Building Standards date back to 1977, and since then, have saved Californians over $74 billion in energy costs and are at least partially responsible for the state’s per capita electricity use staying flat over the last forty years, in stark contrast to much of the rest of the country.