The Green Built Homes program recently certified its 2,500th home — a milestone more than 17 years in the making.
Pioneered by a group of dedicated builders, realtors, and concerned homeowners, the nonprofit Green Built Alliance’s certification program has helped builders measurably reduce the energy use, improve the air quality, and reduce the environmental impact of new homes.
Many of the construction practices we have worked for have withstood the test of time, becoming mainstream as their benefits become more visible. Other practices have evolved as the available technology and methods have changed. Still other philosophical concepts in green building have moved more to the forefront in our minds as we aim to tackle the next technical frontier in reducing a new home’s total impact.
As Green Built Alliance’s new green building program manager, here are four of the most important trends I see in green building:
Heat pumps are an amazing technology. They use some principles of thermodynamics to move heat from one place to another, rather than burning a fuel to generate it, and they actually produce more heating energy than they consume in electricity. They have been around for decades, but have varied in their efficiency, and in how effective they were for home heating when it was too cold outside.
The much-lauded geothermal heating and cooling systems are actually just a specific type of heat pump that uses the ground as the heat source, increasing their efficiency even further. But geothermal’s cousins, air-source heat pumps, are becoming quite efficient on their own these days, and most critically, are becoming effective even in very cold climates where historically they didn’t work so well. That’s important because even air-source heat pumps are far superior to fossil fuel heat for efficiency, further supporting the total electrification of homes (my next coming trend).
Heat pump technology is fast moving into other appliances that might have traditionally used fossil fuels. Take water heating. A new heat pump water heater can generate a stunning 3.85 more energy out for each unit of electricity put in, making them the most energy-efficient hot water choice short of solar thermal.
Heat pump dryers are another development on the heat pump front, offering yet another all-electric way for a standard appliance to deeply cut energy used compared to non-heat pump options.
Natural gas or propane have long been strong fuel choices for the biggest energy users in a home: space heating, water heating, cooking, even clothes drying. And yet, there are now all-electric options for each of these functions that just knock the socks off of other choices on efficiency. (Thanks, heat pumps!) Even transportation, long reliant on gasoline, is moving toward electrification, with electric vehicle (EV) charging stations as a growing feature in new Green Built Homes.
The benefits of total home electrification are many.
- As mentioned, the all-electric options for our common needs — heat pumps for heating, induction ranges for cooking, heat pump water heaters for our water, and even heat pump dryers for our clothes — just use way less energy to begin with than equivalent fossil fuel burning options.
- Electricity can be generated on site with renewable energy, and potentially stored in batteries, even if a home does not do so right away, while even the most efficient of gas-powered appliances must still burn fossil fuel to operate.
- Thanks to consumer demand and state-level policies, grid electricity overall is becoming increasingly renewable and will likely continue moving in that direction.
- Routing all options through one fuel source creates future opportunities for simplification, innovation, and reliability. For example, microgrids can be developed that use community solar to brace areas against blackouts during natural disasters. Utilities can store excess grid energy in people’s heat pump water heaters, and potentially draw on that extra heat like batteries in times of need. Future EV batteries can even act as whole-house batteries tied to an on-site photovoltaic system.
Read more about our region’s efforts to electrify in the articles about our nonprofit’s Blue Horizons Project program on pages 36-39.
This phrase might have seemed an academic one relegated to architectural circles 11 years ago when I first started in this industry. However, embodied carbon has been the talk of the various green building design newsletters that fill my inbox these days, and it’s even worming its way into the thought processes of consumers and smaller green builders.
Considering embodied carbon means comparing the climate impacts of the extraction, manufacture, shipping, and end of use of the products that we buy, and adjusting purchasing decisions accordingly. It’s not a minor deal in green building: the carbon emissions associated with creating the materials used in our buildings make up a whopping 11 percent of total U.S. greenhouse gas emissions, according to the U.S. Information Agency.
Yet understanding embodied carbon is also really hard. How do you consider this when you are buying hundreds of different products from hundreds of suppliers, in a complex supply chain that is dynamic and not very transparent?
Thankfully, the roadmap is starting to form. We know that the Portland cement in concrete is one of the largest components of that 11 percent carbon-emissions puzzle, so minimizing concrete and looking for concrete mixes that use fly ash is one huge step that more builders need to be doing as a matter of course.
As for the rest, there are growing tools to help. One to be aware of is the free EC3 (Embodied Carbon in Construction Calculator) tool developed by the Washington state nonprofit Building Transparency. This tool uses building material quantities and a database of material types to calculate the carbon footprint of a build project. Explore it at buildingtransparency.org.
More and more, we are deciding as a society that companies large and small should have clear, science-based sustainability programs, metrics, and goals. Customers want the products they buy and the builders they use to be engaged.
Corporate sustainability programs range in their scope, from large companies that put out full Environmental Product Declarations (EPDs) on the embodied carbon of their materials (data that gets fed into the EC3 tool mentioned above), to companies making small scale commitments to offset just their shipping mileage—such as some of the local companies described in our story about our nonprofit’s Appalachian Offsets program on page 48.
Even small builders and their customers have opportunities to engage, such as buying offsets, certifying building projects through Green Built Homes, joining a campaign to request that more manufacturers produce EPDs, and more.
Just as green building has advanced from what it was decades ago, so has what it means to be a green company (or a green consumer). We continue to learn how we are all connected in what we do.
Technology continues to advance and lead us toward a grid that is more renewable, and more adaptable overall. I am excited to see what the next decade of green building brings to our region, and I hope that you are too!
Leigha Dickens is the Green Building Program Manager for the Green Built Alliance. She was formerly sustainability manager at Deltec Homes, where she worked for more than 11 years to help clients build greener homes and increase Deltec corporate sustainability. Connect with Leigha at Leigha@greenbuilt.org.
You can also view this article as it was originally published on page 34 of the 2022-23 edition of the directory.