The new headquarters for the Iowa Association of Municipal Utilities will educate the public about the value of sustainable development.

Dedicated June 9, the building focuses on efficient use of resources, including water and energy, as well as technologies that blend with and enhance the local environment.

"Our whole goal is to showcase as many sustainable and energy-efficient methods as possible," explained Patti Cale, IAMU's energy services coordinator. "We hope to reach a lot of outside groups. The building gives us a built-in education process."

HVAC features heat pumps
The 12,000-square-foot building features eight 4-ton ground source heat pumps for heating and cooling. The system features 33 wells that reach 175 feet into the ground-a total of more than two miles of piping. It transfers heat from the earth to the building in winter and discharges summer heat from the building to the ground. The geothermal system reduces electricity consumption by 40 percent compared to other heating or air conditioning equipment.

The building's windows make maximum use of sunlight in work areas. Cale explained that the window glazing is only 15 percent. However, the windows are located near the top of a 20-foot-high ceiling, so the sunlight provides illumination without excessive heat. Photosensors dim fluorescent light fixtures as levels of sunlight change.

Parking lot lights efficient
In the parking lot, the lighting system provides adequate illumination without creating a neighborhood nuisance. The IAMU building is surrounded by residential areas. "We wanted to be a good neighbor," Cale explained. "We didn't want bright lights disrupting the neighborhood."

The result is a bilevel lighting system controlled by photosensors. At dusk, the 150-watt high-pressure sodium lights come on at full strength. All fixtures focus light down to the parking lot, rather than illuminating the sky. This system provides maximum lighting in the lot with minimal disruption in the neighborhood.

At 10 p.m., a timer dims the lights to 50 watts, providing minimal lighting when the lot is likely to be empty. This system reduces energy consumption and accompanying costs. A series of motion sensors and switches return the fixtures to 150 watts when needed.

Volunteers help
IAMU members invested time as well as money in building the association's new facilities.

"Our utilities were put in by volunteers from member municipalities," said Cale. "They also installed some of the site lighting."

The building's airtight envelope further reduces energy use. A foamed-in-place insulation called Icynene fills cavities between wall studs, expanding and sealing every crack, gap, and hole. Icynene gives the walls an insulation value of R-18 and eliminates the need for a supplemental heating system to use with the heat pump. It is more effective than fiberglass insulation at cutting air infiltration and moisture migration, according to Cale.

Grounds focus on sustainability
But the center's sustainable characteristics don't end with energy. The site's soil conservation efforts have been featured in a variety of publications and as a case study on the U.S. Department of Agriculture's land stewardship Web site.

"The grading and construction included a soil conservation demonstration," said Cale. IAMU and the Polk County Soil and Water Conservation District used erosion and sediment control practices from the first day of grading and site development. Temporary sediment basins, constructed wetlands, use of compost, silt fences, fabric ditch checks, and temporary and permanent seeding all contributed to keeping soil on the site.

11-acre prairie blooms
Two other features have added to the natural setting. An 11-acre prairie at the site features plants native to central Iowa. More than 60 species, including coneflowers, goldenrod, and compass plant, bloom across the prairie. Seeds from the plants will go to other prairie restoration projects around central Iowa.

The prairie plants reduce money and resources needed to maintain landscaping. The native plant species don't require watering and successfully battle weeds for water and nutrients, reducing the need for herbicides.

A wetland water treatment system uses plants and gravel to filter and clean wastewater. Soil tests showed that a traditional septic system wouldn't work. The high water table at the building site would lead to odor problems.

Wastewater still goes to a septic tank, where solids settle out. Water from the tank flows into a wetland basin. Bacteria at the bottom of the basin break down waste materials in the water. Wetland plants growing in the basin further enhance the treatment process.

Education efforts continue
Now that IAMU has moved in, the association will continue its educational efforts. Visitors attending meetings, training sessions, and conferences at the building will learn about its sustainability features through a series of signs. For example, a geothermal heat pump conference this summer gave IAMU a chance to showcase its heating and cooling system.

Besides on-site education, IAMU plans to use various media to share information. A booklet explaining the facility's sustainability features is already available. Next up is a Web site featuring actual performance data. System performance is being monitored for inclusion on the site. IAMU is working with the Iowa Energy Center to show other building owners and designers what can be done.