What makes the eight-classroom addition for Langford Elementary a "Green School?" Does it make any difference?
Our goal for Langford, from the very beginning, was to make improvements on anything that consumed resources over the life of the building. The whole team, the District's project manager and their energy consultants, our engineering consultants, and the contractor thoroughly embraced this challenge. We all agreed to look with fresh eyes at all aspects of the project and to find innovative ways to meet this ambitious goal.
There wasn't any one thing that made this a green school. The solutions we devised consisted of a number of best practices that are increasingly available. There were also areas where we innovated, including ways to double-use spaces. We developed signage to show teachers and students how to conserve as they use the building.
We did a lot to save energy with the air-conditioning. A high efficiency system supplies individual units that have separate controls in each classroom. The roof is designed to minimize heat gain, with R-30 insulation and a reflective surface. We designed most of the windows to face north and south. The hottest sun comes from the east and west, so those windows are shaded with deep awnings. The wall insulation completely covers the studs, so they don't conduct heat into the building.
To conserve water, the toilets are "double-flush." This means lower use of water to flush liquids; a fuller flush for solids. To minimize water in landscape irrigation, we specified xeriscaping, or plants that grow with little or no extra watering. A rainwater collection tank gathers runoff from the roof to use when the plants do need watering.
Daylight cuts down on the need for lights. A skylight in the gathering spaces uses a translucent insulated panel. This system diffuses the light so the hallways lights are almost never needed. In the classrooms, windows let light in from both the outside, and from the sky-lit gathering space. The switches for each classroom allow the teachers to turn off each row of lights so they only illuminate the areas that are dark.
We developed informative signs to remind teachers and students that their behavior also determines how much energy is used. We had heard that some teachers in other "green schools" had been leaving the lights on, or complaining when a photocell automatically turned them off. The simple diagram above each bank of switches seems to be working.
Hallways, in most schools, are empty places during most of the school day. Architects usually think of them only as connectors between classrooms. When we designed the front four classrooms, we turned them a slight angle. That made the hallways wider at the ends, so they can function as gathering spaces. Teachers are using these areas as break out spaces for small groups or individual instruction. Without changing the normal program, we still were able to add new functionality by making the better use of the circulation space.
So, has any of this made a difference? Is there any real benefit for all the effort? In order to be considered for the City of Austin Green Building Program, the school's actual performance was evaluated after a number of months in use. The results show a big impact and have earned the project a 4-star rating. The school has now been in use for a full year, so we were able to collect even more relevant data. Langford used almost 20% less water the typical school. The energy savings were even more substantial. The building saved nearly ¼ of the energy that Austin Energy normally estimates for a school.
The obvious long-term benefit is lower operating cost. Austin's school districts are anticipating increased costs for energy and water in the years ahead. They are emphasizing extra investment in sustainable building, though we were able to implement the program without an increase in the budget.
Other benefits are also going to be studied. The day-lighting has created a warm and friendly learning environment. There is an interest in monitoring student performance data in schools of this kind. Early studies have begun to document the connection between a day-lit learning environment and alert, successful students.