Green building strategies and primary focus areas when starting a new build
By Eric Morrill
When it comes to starting a building project, there is a lot to keep in mind. Whether new construction or renovation, there are three primary areas of focus that homeowners and builders should consider. All-Electric California, a design-build contracting firm serving the San Francisco Bay Area, recently completed a sustainability retrofit of a three-unit, multi-family building, using best-in-class green building strategies, and dramatically lowering energy use.
One important goal is to eliminate onsite combustion. Both in new construction and in remodeling, gas has no place in sustainability. The team replaced gas stoves with new induction slide-in ranges, upgraded gas water heaters to electric heat-pump water heaters and decommissioned gas heating. In addition, the team scrapped gas dryers, which were replaced in the different units by either a combination condensing washer/dryer, an electric heat pump dryer or an outdoor laundry line. As the electrical service was initially only 100A for the whole triplex, a service upgrade was required by code.
Insulation and Windows
In addition to fuel switching, they reduced energy use by focusing on the thermal envelope: insulation and windows. For insulation, once all the wiring was complete, the team blew fiberglass into wall cavities, and installed rolled fiberglass in the attic and basement. Windows were selected with Low-E coating options tailored to the specific climate and building orientation.
In temperate San Francisco, where residential utility bills are higher in winter, this meant “high gain” window coatings, allowing for passive solar heating. The units, previously uninsulated and with aluminum single-pane windows, saw immediate improvements in heat retention in winter, as well as comfort in summer. Utility data after completion shows substantial utility savings, and energy use that beats the AIA 2030 Challenge standards for new construction.
Low-Embodied Carbon Heat Pumps
Next, the team turned to the heating system. Thanks to a large Southern-facing facade, the new insulation and windows reduced heating needs so substantially that existing electric heaters were sufficient, even when the main gas heating –in two of the units, this was a feature on the antique Wedgewoods– was removed. In buildings without electric heating, use low-embodied carbon heat pump systems, such as packaged terminal heat pumps, or hydronic air-to-water heat pumps.
Where possible, the team avoids systems with extensive field-installed piping containing HFC refrigerants, such as found in many mini-splits, as these have very high global warming consequences when they inevitably leak. Heat pumps are reversible and can function for either heating or AC, potentially saving costs and space. For an accessible presentation of many of the heating options, homeowners can consult Redwood Energy’s free Zero Emissions brochures.
Since buildings are complex systems, and new products arrive on the market regularly, it’s important to keep the big, long-term picture in mind. These are a few things to keep in mind in order to stay on track for greenhouse gas reduction:
- Passive strategies before active.
For heating and cooling, ensure the building is well-insulated, then use the power of the sun for heat when you need it.
- Less is more.
Install what you need, but skip the extras. Focus on high-quality essentials and stay clear of add-ons that may increase project cost, only to later go unused.
- Use low-embodied carbon materials
Usually, wood is a lower emissions material than metal or concrete. When it comes to other choices –insulation, cooling systems, fixtures– be sure to do your research into how the material is made and the associated climate costs. Don’t be afraid to ask specialists, and always fact-check from a reliable source.
- Reduce, reuse and recycle
Whenever possible, keep and reuse building materials, or even entire buildings. This can mean saving light fixtures during a renovation, or purchasing materials second-hand. In some instances, it’s as simple as not replacing things that aren’t broken (unless they’re gas!). When installing new materials, try to use methods that will allow for reuse in the clean economy of the future.
Eric Morrill is the founder of All-Electric California. He can be reached at email@example.com