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“We’re doing a little social engineering, as it were,” says Jean-Pierre Veillet, of Siteworks, a design-build-operate rental property developer in Portland, Oregon. Veillet mounts an energy-monitoring screen in the front lobby of his residential buildings “That way all the tenants know how much energy everyone is using. They might notice their energy use level is up a little that week, and might go back into their unit and flip off the light switch.”

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In 2016 Natural Resources Canada (NRCan) worked with Reid Heritage Homes in Guelph, Ontario, and four other major builders in Canada, to build net-zero homes. Reid installed energy metres in each home to help homeowners understand what behaviors resulted in the most energy use. “The homes with the energy monitors save about 10% more on energy,” according to Jennifer Weatherston, Reid’s Director of Innovation. “Because people become educated quickly and make different choices, like hanging their clothes on a line outside to dry them.”

Tom Marseille of the US Green Building Council writes that electronic controls with automatic adjustments are usually more effective than involving occupants. He provides an example of people closing interior blinds to eliminate glare, but then not remembering to reopen them for solar gain later.

Products such as the Nest and Ecobee thermostats are described as ‘learning thermostats’ both in terms of occupants learning, and also based on the concept that the device itself ‘learns’ and makes adjustments automatically in response to resident patterns. Three studies of customers in 41 states found average savings of 10% to 12% on heating and 15% on cooling with the Google devices. Thus, the claim that they pay for themselves within two years.

Manufacturers research or isolated anecdotes might not be useful to someone building a business case, so a comprehensive review of numerous studies into energy education and energy savings was undertaken by the US Department of Energy (DOE) in 2014. One of its conclusions was that about 12% was saved when residents are aware of the details of their use. Here is a (somewhat complex) excerpt:

When applied to energy consumption, primarily in residential settings, feedback techniques have resulted in energy reductions of 5 to 12 percent depending upon the specific context and methods used (Froelich 2009; Ehrhardt-Martinez 2010). Furthermore, studies of continuous versus monthly feedback about energy usage show that continuous feedback is more effective in achieving reductions in energy use. Households receiving continuous feedback reduced gas use by 12.3 percent compared to 5 percent for households receiving monthly feedback (van Houwelingen and van Raaij 1989). Other studies find similar results (Foster and Mazur-Stommen 2012). In response to OPower’s Home Energy Reports sent to Minnesota electricity customers, there were verified reductions of 2.10 to 2.27 percent in the first year of the program (Power System Engineering 2010). In another study (Winkler and Winett 1982) based on 19 sets of data from experimental studies, households were informed frequently (usually daily) about how much energy they were using. Study participants who modified their habits reduced their energy consumption, some by as much as 20 percent. Darby (2006) reviewed 38 studies of energy efficiency and found that feedback reduced energy usage by 10 to 14 percent on average.

Another DOE project involved 120 energy dashboards installed “at three sites for 8 weeks. The sustained energy savings at the university lab were 31.5%, the government research lab savings were -5% due to policy changes, and the university office savings were 30%. In particular, the university offices sustained 54% savings over weekends and 79% savings on weekday nights.”

In Vermont a heat recovery ventilator manufacturer has opted for fully automated response, and moved beyond energy savings for its feedback loop. Build Equinox has developed a conditioning energy recovery ventilator (CERV) that uses air sensors to continually monitor carbon dioxide and volatile organic compounds (VOCs). It then ventilates as required to maintain fresh, healthy air. The CERV sensors detect C02, methane, propane, butane and 19 high and medium high VOCs, including acetone, sodium hypochlorite, and Windex window cleaner.

Whatever you want to monitor and whatever the actual energy saving numbers might be for your project, if applicable, it seems as if a little education/feedback for either occupants or for smart machines is a good idea; and an increasingly common element in modern HVAC systems.