DISPLAY ENERGY CERTIFICATES COMMERCIAL BUILDINGS
by landlord and tenant, and provides details of water usage for the whole building. Justin Snoxall, head of BL’s business group, says the reports and engagement with tenants is helping to cut energy use by huge amounts across its portfolio. ‘We review energy ratings regularly with
77 Gracechurch Street has saved 60% in energy bills since 2009
each tenant, and see who is not achieving reductions. It’s becoming self-fulfilling. They come to us to see what they could be doing to reduce energy use,’ says Snoxall. From 2009 to 2012, BL cut landlord- influenced energy by 27% across its portfolio, enabling it to cut tenant bills by £3.3m. It is aiming for a 40% reduction by 2015. Paul Edwards, head of sustainability at property firm Hammerson, is also supportive of DECs. ‘They are a common language by which people can make decisions, whether they are tenants, investors or landlords.’ Edwards says Hammerson is considering performance-based contracts to ensure actual energy use mirrors theoretical performance at design stage. ‘If we link energy performance certificates with DECs, we can put performance contracts in place,’ he says. Edwards is chairman of the Better Building
The Manhattan project
New York leads the way when it comes to mandatory energy ratings in the US. In 2009, Mayor Michael Bloomberg announced plans for mandatory benchmarking for private buildings more than 50,000 ft2 (4645 m2)and public buildings, more than 10,000 ft2 (929 m2). The policy is central to NYC plans for reducing CO2 by 30% by 2030. As part of the NYC’s Green Greater Buildings
Plan (GGBP), buildings are graded using the government-backed energy performance rating system, Energy Star. Building managers file details of energy and water use in the Energy Star Portfolio Manager and this is kept on record at the NYC Department of Finance. A building will receive an Energy Star if it is in the top quartile of energy performers for its building type. Andrew Burr, director of building energy performance policy at building performance consultant IMT, says New York and other US cities use Energy Star because it is established and, more importantly, free to use. But Robert Cohen, technical director at energy consultant Verco, says the rating has its drawback. ‘Only the top quartile get an Energy Star so it’s relative, not absolute. You could be rewarding the equivalent of an E-rated building if every other one is an F.’ To identify measures that improve
28 CIBSE Journal February 2013
performance, mandatory reports based on energy audits will be rolled out from 2013. The reports must be carried out by approved energy auditors such as ASHRAE. Valid for 10 years, they include the commissioning of HVAC systems in existing buildings. Last autumn, NYC published a benchmarking for private buildings and then revealed
report2
the Green Star ratings of office buildings. There were some surprises: 7 World Trade Center has a gold LEED rating, but narrowly missed a Green Star with a score of 74, while ‘30s architectural icons, the Chrysler Building and Empire State Building, achieved scores of 84 and 80. Burr says disclosure is the first step towards identifying the energy use in buildings and understanding the measures needed to improve energy efficiency.
Tenanted spaces aren’t measured separately, so landlords cannot determine the tenant’s share of energy use. America has yet to adopt asset rating tools such as EPCs, which enable energy managers to assess fabric and systems. Early adopters, such as New York and San
Francisco, are inspiring other cities to look at mandatory ratings. ‘Cities are focused on economic development, and anything that provides jobs, reduces carbon emissions and cuts energy costs will be welcome,’ says Burr. He adds that the momentum is coming from local businesses calling on councils to help drive the energy improvement market and create jobs. This explains why Minneapolis, a conservative city in middle America, is set to adopt operational ratings in the coming weeks.
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SONGQUAN DENG / SHUTTERSTOCK
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