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Measuring Productivity in Green Buildings

February 2010

A look at one of the first Green Star certified buildings in NZ - Meridian Building, Wellington.

Green buildings consistently outperform non-green buildings in terms of comfort and productivity. Natural light, fresh air and access to views of the outdoors, as well as control over their individual workspace temperature and lighting, can positively affect workplace productivity.

For example, a post-refurbishment study of 500 Collins Street in Melbourne found a 9% increase in typing speeds of secretaries and a 7% increase in lawyers' billings ratio, despite a 12% decline in the average monthly hours worked.

At the City of Melbourne's CH2, Australia's first 6 Star Green Star - Office Design rated building, productivity has risen by an impressive 10.9% since staff moved into their green office, with an estimated annual cost savings of $2 million.

Green schools are also more productive places to work and learn. The Heschong Mahone Daylighting Study (1999) of more than 21,000 US students showed a dramatic correlation between daylit school environments and student performance, including 20% faster progression in maths, 26% faster progression in reading and an increased performance of up to 10% simply by providing students with views out of windows. Quentin Jackson, eCubed Building Workshop, reports on some of the productivity results from one of New Zealand's first Green Star - Office Design certified buildings in New Zealand.

 

Quentin Jackson, eCubed Building Workshop, reports on the productivity results from the Meridian Building in Wellington one of New Zealand’s first Green Star – Office Design certified buildings.

The results of Pre & Post-Occupancy Evaluations allow building occupiers and managers to understand how a building is used by its occupants and to undertake optimisation of the building’s systems.  This can result in a building providing a more comfortable working environment for its users while potentially improving its energy efficiency. Certainly for Meridian it has proven to be a useful tool in the successful design on the Wellington Waterfront.

Prior to commissioning the design of their new building Meridian, the organisation spent a lot of time understanding how their office buildings were working, and what they could learn from their staff about what makes their working environment productive.

In 2005 a Pre-Occupancy Evaluation of the Meridian staff was undertaken.  This was done using an occupant survey method developed by Building Use Studies (BUS) and administered by eCubed Building Workshop to assess the occupants’ satisfaction with internal conditions of their existing premises.   The questionnaire measured perceived satisfaction by asking 63 questions across 12 areas.  This method is used to assess how the building performs on ten important variables (comfort, lighting, noise, design etc). This aimed to determine occupants’ feedback on the performance of their old building, and to compare this with the Building Use Studies’ (BUS) New Zealand and international benchmarks.

Of all the statistics produced from this survey, perceived productivity receives the most attention, although it is the most difficult to define and measure properly.  Although productivity is based on occupants’ subjective estimates of performance (there is no practical method of measuring productivity "objectively" in a building), the technique has been used across many buildings and gives relative picture.  This figure was one of the key variables in determining the success of the new building.

Using this information a Building Performance Specification (BPS) was created to help guide the design team as the goals, aspirations and required performance metrics Meridian required.  The design team was required to constantly check their progress against this BPS throughout the design and construction period of the new building.

After a year of occupation of the new Green Star certified Meridian Building (allowing staff a chance to get over the "holiday effect" of simply enjoying their new offices) the same occupant survey was applied to determine if the new building had met the standards and requirements set down by Meridian during the design phase.  Worldwide post-occupancy study data has  shown that there are perceived differences in productivity of up to 25% between comfortable and uncomfortable staff. The results of the survey showed that using the international data set, the staff perception of their productivity in the Meridian building correlates well and is closely related to comfort in the building. Meaning that as people are very comfortable in this building they are therefore productive.

At the time of the survey in 2008 the New Zealand benchmark for productivity was minus 2.69%, with the international benchmark at plus 3.45%. The productivity score at the Meridian building is plus 8.96%. Meaning occupants think that the  building boosts their productivity at work by about 9% compared with their experience of other working environments.

The Meridian Building was rated highly by staff, achieving a level of occupant satisfaction in the top ten-percentile of the 2007 BUS New Zealand Benchmark data-set relevant to comfort, and rated number two (out of the approximately 20 buildings surveyed at that time) in New Zealand of all the buildings surveyed. On this basis, the Meridian Building is considered very comfortable, with excellent scores for satisfaction and comfort and compares well in the national and International markets.

Comparatively speaking the new building outperforms the former Meridian office buidings in all areas, particularly perceived productivity.

- Quentin Jackson, eCubed Building Workshop, February 2010