Office building plug and light loads: Comparison of a multi-tenant office tower to conventional assumptions

Pressure to conserve energy in commercial buildings is increasing in order to meet nationwide greenhouse gas reduction targets. In the commercial building sector, multi-tenant buildings are common, where offices often receive yearly electricity bills based on their occupied floor area and not actual electricity consumption. This results in diffused responsibility for electricity consumption and little to no usage feedback or incentive to conserve energy. In this study, two office towers in Eastern Ontario installed submeters to accurately bill tenants for their electricity use. One year of tenant plug and light electricity use gives insights into and valuable high-resolution data for office electricity use across 32 submetered commercial building floors. Results find that commercial tenant electricity use, between tenants, is highly variable; that tenant controlled plug and light loads are lower than ASHRAE design values; and, that tenant plug loads are not fully shut off at night. Electricity use feedback is also assessed anecdotally for its impact on tenant energy use behaviour. The ideal level of submetering is discussed for the purpose of providing useful electricity use feedback to tenants.