Big Spring State Hospital is seeking a contractor to provide air filter changing services for State-owned buildings at Big Spring State Hospital in Big Spring Texas. Buildings may be added or deleted during the term of the Contract with a 30-day written notification to the Contractor utilizing the same terms and conditions stated herein. Detailed Information on building, HVAC equipment locations, filter type, size and quantities, schedule, and frequency of change are detailed in Exhibit H Maps and Details. Contractor must be able to service all buildings listed below, and any additional buildings added at a later time. Additional buildings and services will be addressed in a change order, with additional cost allowed based upon proposed pricing approved by the Agency.