Construction guidebook points way to efficient new buildings

Building energy efficiency into new construction is easier than teaching an old building (or building owner) new tricks. But many designers and builders still need schooling in energy-efficient construction—lessons that can be found in the New Construction GuideRedirecting to a non-government site.

The New Construction Guide from the New Building Institute offers a whole-building approach to achieving deep energy efficiencies in new building projects. (Art by New Building Institute)

The New Construction Guide from the New Building Institute offers a whole-building approach to achieving deep energy efficiencies in new building projects. (Art by New Building Institute)

The latest offering from the New Building Institute’sRedirecting to a non-government site (NBI) Advanced Buildings tool suite is a whole-building, step-by-step approach to new commercial construction projects that result in efficiencies up to 40 percent higher than conventional buildings. Building design and construction professionals can reference the New Construction Guide to define high performance in building envelope, lighting, HVAC, power systems and controls.

Learn from experts
The people behind the guide know how to achieve efficiencies without adding costs. The primary authors include NBI’s Technical Director Mark Frankel, Program Manager Sean Denniston and Project Manager Mark Lyles. Collectively, they bring decades of experience in improving building performance and strengthening building codes nationwide.

Technical contributions came from experts across the construction and building systems industry. The fields of energy efficiency and resource conservation, design, research and policy are well represented along with specific systems such as lighting, heating and cooling and building controls. The ASHRAE 90.1 standardRedirecting to a non-government site, the International Energy Conservation CodeRedirecting to a non-government site and the Consortium for Energy EfficiencyRedirecting to a non-government site were referenced for lighting and mechanical equipment performance levels. The guide also ties the measures to utility energy efficiency programs.

Modeling methodology
Underpinning the New Construction Guide is an extensive energy modeling protocol. The authors evaluated energy-efficiency measures using eQuest building energy use analysis software to conduct more than 100,000 modeling runs on prototype buildings.

They applied three to five measures to each building prototype and ran energy use analysis in ASHRAE’s eight identified climate zones represented by 16 US cities. Measures were only included if they offered savings beyond the baseline buildings in most scenarios, or significant savings in specialized cases. Once the most effective individual measures were identified, they were all applied as a package to each building prototype in each climate scenario to get predicted savings for the program as a whole.

Power providers get involved
The New Construction Guide has several utility sponsors who independently modeled the measures and validated the approach and methodology.

Ralph DiNola, NBI executive director, would like to see utilities incorporate the guide into commercial building incentive programs. “For example, some of our utility partners are offering builders dollars per square foot for implementing the guide,” he said. “Those programs have delivered cost-effective energy savings at a lower cost than other utility incentive programs.”

Utilities including ComEdRedirecting to a non-government site and NSTAR Electric and GasRedirecting to a non-government site have worked with builders in their territory to implement measures from the Core Performance Guide, the previous edition of the new guide, in local projects. Energy program administrator Efficiency MaineRedirecting to a non-government site and the transmission and distribution network National GridRedirecting to a non-government site both have building projects in the pipeline that implement the New Construction Guide.

Municipalities that have LEED [Leadership in Energy Efficient Design] requirements for new public buildings will find yet another use for the guide. The United States Green Building CouncilRedirecting to a non-government site allows the program to be used to achieve energy prerequisites and credits for LEED certification, on the version of LEED. 

About NBI
Established in 1997, the New Building Institute is dedicated to improving the energy performance of commercial buildings by providing policy and program direction, and promoting best design practices and available technologies. NBI’s board of directors comprises leaders in the energy efficiency and green building industries, including representatives from utilities like Pacific Gas and ElectricRedirecting to a non-government site.

The Advanced Building program promotes high performance buildings with technical tools and educational resources such as case studies, webinars, reference guides and research findings. Sponsors and supporters include the Department of Energy, Energy Center of WisconsinRedirecting to a non-government site and New York State Energy Research and Development AuthorityRedirecting to a non-government site.

NBI welcomes involvement from utilities. To learn more, contact NBI at 360-567-0950, or visit the speakers bureau for links to presentations.

Ask the Energy Experts: Reduce energy use in commercial bathrooms

Question:eexpert_small
Can you recommend ways to save energy in commercial bathrooms?

Answer:
Commercial bathrooms offer many opportunities for energy savings. Bathroom efficiency measures can have a positive effect on any business, but hotels, schools, recreation centers and other facilities with large multiple bathrooms can really benefit from the following measures.

Insulate piping
Most codes require insulation for hot-water piping, but insulation may have been damaged or removed during maintenance operations. Replace it with the minimum insulation required by your jurisdiction’s most recent energy code, or better. For example, the Washington State Energy Code requires a minimum of half an inch of insulation, with a conductivity between 0.24 and 0.28 (roughly R-4 per inch) for supply lines up to 2 inches in diameter, and 1-inch insulation for piping up to 4 inches in diameter.

Reduce flow
Reduction of domestic hot water (DHW) consumption can be accomplished by limiting the flow rate from fixtures, automatically shutting off the hot (and cold) water after a measured time interval and reducing supply temperatures. The first two measures are required by most plumbing codes for facilities open to the general public. Flow rates are usually limited to 2 gallons per minute (gpm) with the requirement that the valve self–close within 30 seconds. Self-closing faucets can save money and energy – and prevent vandalism. Also, the Building Energy Software Tools Directory, by the Department of Energy, provides links to several useful general water conservation software tools.

Reduce temperature
Many codes and statutes also limit the maximum temperature at lavatories in commercial buildings to 120 degrees. Resetting the water heater thermostat to deliver 120-degree water is usually a simple and cost-effective way to save energy in bathrooms. For water heaters serving additional, higher temperature hot water loads (dishwashers, etc.), equip the fixture with a thermostatic mixing valve or a booster heater for the higher temperature loads.

Control recirculation
Larger commercial buildings usually have systems to recirculate hot water from the most remote hot water fixture back to the water heater. The idea is to keep the water in the distribution piping hot at all times and reduce the time a user must wait for hot water. Many state and federal energy codes now require a time clock or other automated means to shut down the hot water recirculation pump during unoccupied hours. These controls save energy by eliminating heat loss from the recirculation piping when the building is unoccupied. They also cut the run time and electrical consumption of the recirculation pump by almost half.

Upgrade lighting
Bathrooms are occupied only intermittently, usually less than 20 percent of the time. That makes bathroom lighting in a commercial establishment the perfect application for occupancy sensors that turn off the lights when the bathroom is not in use.

Recover heat
Exhaust systems are another energy-user in bathrooms. In larger commercial buildings, a single fan often serves several bathrooms and it runs during the occupied hours. In small commercial buildings, the exhaust fan is often wired to the light switch and only runs when the lights are on. This can lead to under-ventilation of the bathrooms and indoor air quality (IAQ) problems. Modifying light switch-operated fans to run during the occupied hours will increase building energy use slightly, but will improve IAQ.

You can make up that loss by using the moist exhaust air leaving the building to preheat (or cool) outside air. Learn more about heat recovery ventilatorsRedirecting to a non-government site, from the Energy Efficiency Emerging Technologies Database. This collection of practical, commercially available, but not yet widely used energy efficiency technologies is regularly reviewed and evaluated by energy experts and engineers.

Upgrade heating system
Bathrooms are usually located in the core of larger buildings with no outside walls. However, some smaller buildings have bathrooms on outside walls that need to be heated in winter. The heat source for outside wall bathrooms is often an electric resistance heater that runs constantly. Consider installing a programmable thermostat (line voltage or 24v. as appropriate) or a connection to the building energy management and control system to limit operating hours and save energy.