LEED Gold | 2025 | 17,800 sq ft | Des Moines, Iowa

• Integrative process to optimize materials & design

• Natural ventilation system

• 80% of structure was pre-engineered

PHOTO: © COREY GAFFER PHOTOGRAPHY

PHOTOS: © COREY GAFFER PHOTOGRAPHY

• Grows over 230,000 plants each year

• 41% reduction in indoor water use

• 53,000 sf of native site plantings

Architect: MA Architecture
MEP & Structural Engineer: IMEG
Contractor: GTG Companies

Commissioning: SystemWorks

Landscape: Confluence

Civil: LT Leon Associates

LEED Consultant: C-Wise Design & Consulting

• Solar array can power the entire building

• 19% reduction in energy use

• No permanent irrigation required

The City of Des Moines Greenhouse is one of a few all-electric greenhouses in the entire world. Due to the unique heating and moisture control needs of a greenhouse, an all-electric building required innovative strategies and cutting-edge thinking, and the project team conducted extensive research on greenhouse design and systems to pull it off. The new Greenhouse provides Des Moines with a year-round location to grow a variety of plants that will serve to beautify locations across the city.

If a building project decides to provide any energy from gas or oil, they must later undergo costly renovations to move away from those sources if they want to retroactively “green” their building. All-electric buildings offer an important alternative as they have the ability to become more sustainable over time—all of their energy use comes from the grid, so as the grid shifts to be increasingly powered by renewable energy sources, so will the building.

The Greenhouse took advantage of this by utilizing an electric boiler for interior heating as well as an air source heat pump rooftop unit. The nearby solar array that the project shares with the City of Des Moines Animal Control facility is capable of generating 142% of the building’s total energy needs, and building efficiency measures decreased energy usage by 19%. The inclusion of a natural ventilation system instead of a swamp cooler (evaporative cooling system) further increases energy efficiency and maintains a consistently cool and comfortable interior environment for occupants.

In addition to growing plants that will eventually support the ecosystem in different parts of the city, the landscape of the site provides a wealth of habitat and ecosystem services to its surroundings. Achieving the maximum number of LEED points in this category, the landscape features biocells and bioswales that allow the site to process and retain almost triple the amount of water that falls in a 90^th percentile rain event, meaning rainfall is able to infiltrate through plants back into the earth instead of running off pavement and collecting pollutants. The landscape totals over 53,000 square feet of native prairie and pollinator plants that require no permanent irrigation, saving massive amounts of water and providing important habitat for the pillars of nature.

• 100% of occupied space has daylight access

• All-electric