Franklin Public Library

Des Moines, IA

The Franklin Library renovation and expansion project was driven by the creative minds of highly skilled engineers who collaborated to pursue cutting-edge mechanical and electrical systems designed around two main criteria: energy efficiency and ease of maintenance.

  • The 28,000 square foot building (14,000 existing) utilizes the highest efficiency chiller and boilers available on the market while using an air to air energy recovery ventilator to capture the energy in the exhaust air stream to pre-treat the required outdoor ventilation air.
  • The boilers are 98 percent efficient
  •  Due to the mechanical system and solar energy production, the library consumes 59 percent less energy per year than a code minimum building
  •  Over-ventilating – 30% was over ventilated to help indoor air quality to prevent building sickness syndrome
  •  Building content was recycled – approx. 90% of all waste was directed away from landfills
  •  Used 80% of existing building
  •  White Membrane Roof – Highly Reflective – to reflect the heat back
  •  Low Mercury Bulbs
  •  The uniqueness of the library as an architectural milestone was preserved


LEED certification is the recognized standard for measuring building sustainability, and achieving LEED certification for a project, demonstrates that your building project is in fact “green.” The LEED green building rating system, developed and administered by the U.S. Green Building Council, is designed to promote design and construction practices that increase profitability while reducing the negative environmental impacts of buildings and improving occupant health and well-being. Platinum LEED Certification is the highest certification available on the rating system and was awarded to Franklin Library. For more information on LEED, please visit


Two forms of solar energy are produced on site: solar thermal panels and photovoltaic panels. During sunny fall and spring conditions, the solar thermal panels and photovoltaic array can provide 80% of the building’s energy needs.


There are 54 Solar Thermal Panels located on the roof, producing 2,000 therms of energy per year. These provide hot water for domestic uses and for the boiler system.


There are 138 Photovoltaic Panels, which will provide nearly 50 kW of peak power while saving the library 78,624 kWh of electricity per year.


Efficient lighting is used throughout the project with all of the site lighting and the majority of the interior lighting consisting of LED lamps, most being controlled via day light sensors. This in turn is able to provide a 60 percent savings in lighting consumption compared to a code compliant building and also limits the need to replace bulbs and lighting ballasts.


The mechanical equipment is centrally located in one location, eliminating the need for maintenance personnel to perform routine tasks in the patron areas. Ceiling spaces are also clear of valves, strainers, and filters to avoid leaks and the need for ladder access.


Franklin Public Library


Des Moines, IA




Benjamin Design Collaborative


28,000 Sq Ft

Completion Date

Fall 2009

Government, LEED, Libraries