The City of Houston’s retrofit program covers a portfolio of 271 city buildings encompassing 11 million square feet. Similar buildings are grouped into sub-projects, or tranches, and retrofit together; the implementation of each tranche is phased over time. Because the buildings under retrofit were occupied by city employees and in active use by the public, the project required a high degree of schedule coordination between the building occupants, the city, and the ESCOs.  Schneider Electric/T.A.C. and Siemens – the two ESCOs undertaking the retrofits – made a concerted effort to avoid construction during peak hours of public demand. For instance, lighting retrofits were done at night, and major plant upgrades were made over weekends or holidays to avoid interruption of service to taxpayers.

This particular case study provides an overview of the Schneider Electric/ T.A.C.’s and Siemens’ Tranche 2 retrofits. The retrofit program became a keystone of former Mayor Bill White’s commitment to transform Houston from “energy capital” of the world to the “energy conservation capital” of the world and has since been a foundation element for current Mayor Annise Parker’s sustainability initiatives. 


The need to adhere to the public procurement requirements of the Texas Government Code posed another challenge to the city by restricting its ESCO selection criteria to qualifications only. The city was therefore unable to assess the relative cost of the proposals put forward by the ESCOs at the RFP stage. Moreover, the cost savings projected by the ESCOs after the audit by Texas Government Code must be reviewed by an independent third-party licensed professional engineer, adding another bureaucratic step to the process. The process of choosing a partner based on qualifications, not cost, was not new to stakeholders in the city.


Key findings from Tranche 2 include retrofits performed by Schneider Electric/T.A.C. to police stations and general governmental buildings.  This project covered 1,934,035 square feet in 15 buildings at a cost of $23,148,472.  Retrofits included central plant redesign & replacement, lighting upgrades, water upgrades and building automation control upgrades.  This retrofit saves 7,218 tons in annual emissions and $1,964, 842 in annual energy costs.

Siemens, executed the Health & Human Services Department (HHSD) project as one of five components. The project covered 939,141 square feet and 24 buildings at a cost of almost $7 million. Retrofits included HVAC efficiency improvements and installation of an energy management system, lighting improvements, and plumbing fixture upgrades, each of which contributed to overall energy savings. This retrofit reduced annual emissions by 1,903 tons and saved $852,995 (22%) in annual energy and maintenance costs.  Similar results are available for retrofits in Solid Waste and the Parks & Recreation Department.

Read the full case study, including all results, here.