Defining Lighting Quality Based On User Satisfaction

Lighting quality is a critical consideration in effective lighting design, and often should take priority over energy savings and the economies of cost. But what is lighting quality?

It goes beyond energy and cost and light levels to include brightness, light distribution, color, aesthetics, daylight, ease of use for controls, and other issues. While many of these are covered by individual recommendations and metrics enabling optimization for a given space, there is no single lighting quality metric.

Rather than pursue a single objective metric, perhaps the right approach is to give building owners and designers the tools they need to evaluate lighting quality subjectively, based on user satisfaction, on an application by application basis.

For the office lighting market, the Pacific Northwest National Laboratory (PNNL) has done just that. Funded by the Lighting Controls Association, National Electrical Manufacturers Association, General Services Administration and the Department of Energy, PNNL’s Light Right Survey offers a free tool for office building owners and managers and industry practitioners.

Residing here, the Light Right Survey includes 50 questions which can be used to profile the respondents, inventory what type of lighting they are using in their workspace, determine how satisfies they are with their lighting conditions, and gauge their lighting preferences.

Questions span all aspects of lighting quality, with controls-related questions asking users if they can control their task lighting, whether and how they can control their overhead and task lighting, whether the overhead lights automatically turn OFF (and ON) based on occupancy, and how satisfied they are with their controls.

The results can be used as a diagnostic tool to find problems and correct them, measure the effectiveness of lighting approaches and improvements or justify proposed improvements, increase communication between lighting decision-makers and lighting users, and identify lighting strategies that increase worker satisfaction.

“Lighting provides a great opportunity for increasing worker satisfaction, reducing a building’s operating costs, and saving energy,” says Tracy Beeson, LC, Energy and Environment Directorate, PNNL. “There is no better way to understand the acceptability of a lighting system than to ask the people who live and work in the space.”

Multiple surveys can be conducted by the survey manager using a simple interface.

Data results can be viewed as raw numbers, in an HTML executive summary, and in an advanced report presenting the data in a narrative format with suggested ways to correct possible problems.

Philips is currently supporting a new feature allowing photos of actual lighting equipment to be uploaded into the survey. In the future, PNNL may aggregate data into a national database, allowing benchmarking.

This is an exciting tool for the lighting industry, providing the basis for conversation between building owners and managers and lighting users, and between building owners and managers and lighting practitioners, about lighting quality and its effects. For lighting practitioners, it provides opportunities to support clients by interpreting survey results, validate their work, and help clients justify investment in new lighting approaches that prove effective.