Passive design: Reaping the rewards

Interface's Passively Designed Factory
Chatham, North Carolina

A previous Environmental Lovins post described the revival of passive design -- using the sun's energy to light, cool, heat and ventilate a building's interior.

As we discussed, passive design is a critical tool in helping buildings capture dramatic energy savings. Less well known is that passive design also creates superior living spaces.

Studies have documented how passively designed structures improve the productivity, health, and luxury of the indoor environment.

The story of a North Carolina Fabric Company's retrofit, in particular, provides proof. And because it was a retrofit, analysts were able to measure changes -- in worker morale and productivity --  derived directly from passive design. 

Chatham Manufacturing Company, a famous blanket making and commercial interior fabrics company, was in serious economic trouble when acquired by Interface Corporation. To boost morale, corporate management at Interface decided to allot $3 million dollars for capital improvements.

The managers' sound instincts also led them to stipulate that the retrofit plans maximize the use of passive design, both to improve the comfort of their workers and to reduce energy costs.

In the end, with input from Rocky Mountain Institute, engineers chose to maintain the indoor temperature by using water from a nearby pond. They added insulation to exterior facing walls and replaced windows and overhead doors with newer, heat-blocking versions.

Designers decided to paint the interior white, maximizing the sun's light. 124 skylights were installed and 2000 lamps retrofitted. Intelligent environmental monitoring and control systems adjusted mechanical lights based on the level of sunlight indoors.

When completed, managers noticed a distinct change in their employees.

Daylight improved weavers' line of sight, allowing them to better set their looms. The new, predominantly natural cooling system improved heat and humidity levels, boosting the quality and consistency of weaving.

Overall, weaver efficiency increased by 10 percent, saving the plant $5000 a week in labor. The use of passive design eliminated the need for new, expensive mechanical equipment meaning the project came in $1.2 million under budget. Electricity reductions continue to save Interface half a million annually.

The Chatham plant retrofit shows the potency of combining modern technology with passive design.

Because they could not start from scratch, designers and engineers were somewhat constrained. Yet they still managed to create an indoor environment where workers could be more comfortable, productive, and happier, allowing the company to pull itself out of its economic troubles.

The Chatham factory is just one of many modern, passively designed structures. In combination with modern technology, passive design has enabled builders to construct what was once thought impossible: homes and offices that produce more energy than they create.

Maria Stamas is an analyst at Rocky Mountain Institute.