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  • Green built vs. Energy Star, what does it mean and how does it differ?

    Wednesday, November 9, 2022   /   by Amy Brown

    Green built vs. Energy Star, what does it mean and how does it differ?

    As concern for our immediate environment and our planet grows and we see the impact that our lifestyle has on future generations, terms such as green building and energy star are becoming major considerations in the construction industry. But with those terms comes wide differentiation and a bit of confusion as consumers can misconstrue what those terms realistically mean and what they are actually getting when they purchase an eco-friendly home.

    So let's talk about what these terms mean and what products they encompass.

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    “Green building” is defined as “the practice of creating structures and using processes that are environmentally responsible and resource-efficient throughout a building’s life cycle from sitework to design, construction, operation, maintenance, renovation, and deconstruction.

    Green building is actually a class of materials and building products certified by a third party and has many levels and programs. A home can be a LEED (Leadership in Environmental and Energy Design), HERO (High Efficiency Residential Option), EnergyStar, or simply HERS (Home Energy Rating System) rated and still be considered green. North Carolina has a statewide certification program called GreenBuilt NC that oversees its third party certification. 

    The GreenBuilt Homes Program encompass all aspects of environmental design and construction including:

    • SITE AND LANDSCAPE: healthy outdoors by using erosion control and saving existing trees

    • WATER EFFICIENCY: lower water bills by using high efficiency irrigation and plumbing fixtures

    • BUILDING ENVELOPE: lower utility bills by using high efficiency windows and insulation

    • HEATING AND COOLING SYSTEMS: higher comfort with efficiency equipment and sealed air ducts

    • APPLIANCES AND LIGHTING: lower utility bills by using Energy Star appliances and lighting

    • INDOOR AIR QUALITY: a healthy interior with non-toxic finishes and minimizing moisture

    • MATERIALS: a low maintenance home using durable, local, and recycled content materials

    What you need to realize as a consumer is that not ALL of these features are necessarily included for every green build. GreenBuilt NC has a checklist and for every additional item completed the home has the potential to increase its rating. 

    The rating categories are: Certified, Silver, Gold, Platinum, Net Zero Ready, and Net Zero Energy.

    I have attached a guide below for more details on what products you receive for each category class.

    You can also read more about GreenBuilt NC at https://www.greenbuilt.org/programs/green-built-homes/

    What is a HERS score?

    The Home Energy Rating System (HERS) provides a national standard for measuring the energy efficiency of a home. 

    How Rating is Determined

    A HERS rating is a number that indicates the energy efficiency of a home and has been likened to the “miles per gallon” ratings for automobiles. The rating is determined by dividing the projected energy consumption of the subject home by the projected energy consumption of a reference home and multiplying by 100. The “reference home” is a home of the same dimensions in the same climate zone that is built in compliance with the standards of the model energy code and has an assigned HERS index of 100. The software used to calculate the energy consumption of a home considers the areas and insulation values of the walls, windows, ceilings, floors, etc. (often referred to as “the thermal envelope”), the efficiency of the heating, cooling and hot water systems, the lighting systems, the appliances, and energy loss through air infiltration and duct leakage.

    Under HERS, homes are rated on a scale of 0-150 with the reference home rated at 100. In residential evaluations, the higher the number, the less efficient the structure.

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    This term can be a bit confusing as you navigate the green building market so let's clarify what Energy Star means and what it covers.

    The Energy Star label confirms that one of the major goals of green building, e.g., energy efficiency, has been accomplished. Energy Star is the only government backed certification program for energy efficiency and it independently establishes the qualification criteria in the various product categories to earn the Energy Star label.

    The Energy Star website frequently refers to “green building” or “green homes” which, unfortunately, may give the public the impression that Energy Star certification means a building is “green-built,” which technically is not true. The criteria for qualifying a structure as “green-built” goes far beyond considerations of energy efficiency alone. The Energy Star website acknowledges this reality in subtle statements such as “energy efficiency is the place to start” when looking for a green home and that a homeowner will have addressed “two critical green home elements” when purchasing an Energy Star Qualified home.

    Also, the presence of Energy Star appliances DOES NOT mean that a home is Energy Star certified.

    At a minimum, to qualify for Energy Star certification, a house must be at least 15% more energy efficient than one built in compliance with the applicable energy conservation code.

    There are also different levels to Energy Star certification so please question your builder and/or realtor to see which designation your home is certified under. 

    More information on Energy Star can be obtained at www.energystar.gov


    I hope that this takes a bit of the mystery out of the green building movement. Just remember to ask questions and to use your realtor as a resource.