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The goal of this discovery phase is to gain an initial understanding of the building’s existing conditions, current challenges and potential opportunities. The data and insights gathered during this phase will be used to create the building’s calibrated energy model.  Key activities in this workstream include: 

  • Collecting and reviewing relevant building information 
  • Observing building operations under different conditions 
  • Testing subsystems and their interactions 
  • Creating the Business-as-Usual (BAU) base case 

This workstream is critically important for several reasons.  First, it grounds the team in the reality of the building’s current performance. It also helps build a jointly owned process of uncovering early energy or carbon reduction opportunities that can increase trust and enthusiasm to identify more complex measures as the project progresses. 

At the end of this phase, the team should have a clear understanding of the building energy systems, its historical energy and carbon profile, the potential impact of local laws or other building requirements, opportunities for additional metering, and preliminary energy and carbon reduction opportunities.  


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This workstream provides vital information on current challenges, near and longer-term carbon reduction opportunities and the accuracy of the energy model. It also creates early wins that build momentum and trust. Getting the most out of this work requires trust-based collaboration across facilities managers, operations staff, the energy modeler, external contractors and design engineers. Engaging with tenants to get insight into what drives their loads can also be valuable to the process. Data and insights on the existing conditions of the building typically arise from four sources: 

  • Design documents 
  • Data from metered systems 
  • Direct observation and testing 
  • Building operations team feedback 

Each source is important, but it is the integration across these four categories of data that leads to deep operational insights and identification of major areas of opportunity.  


Getting the most out of this work requires trust-based collaboration across facilities managers, operations staff, the energy modeler, external contractors and design engineers. Engaging with tenants to get insight into what drives their loads can also be valuable to the process. 


Gather Information: In this phase, project teams should work with the building management and operations teams to collect the information shown below here in the sample Information Gathering Checklist: 

Collected Information 

Why is this Information Needed? 

Architectural Drawings 

  • Floor Plans 
  • Elevation Drawings 
  • Vertical Floor Dimensions 
  • Tenant Fit-out Drawings 
  • Façade Cut/Detail Sheets 
  • Window Cut/Detail Sheets 

Architectural drawings will be used to build the energy model geometry and assign performance characteristics to exterior wall assemblies.  

Mechanical, Electrical and Plumbing Drawings 

  • Mechanical Schedules 
  • Mechanical Riser Diagrams 
  • M-Drawings (Schedules) of Retrofit/Upgraded Equipment or a Description of Changes 
  • Electrical Schedules 
  • Electrical Riser Diagrams 
  • Lighting Schedules and Detail Sheets 
  • Plumbing Schedules 
  • Plumbing Riser Diagrams 

MEP drawings will be used to build the energy-consuming systems in the energy model. These documents will also inform opportunities for equipment replacements based on end of useful life and can be referenced when evaluating equipment locations and available space. 

Utility Data 

  • Minimum 12 months of data for all incoming utilities including electricity, natural gas, district steam, fuel oil.  
  • Data from tenant electrical sub-meters (if available) 
  • Data from central plant BTU meters (if available) 

Building utility bills showing annual energy consumption and tariffs are required to create an initial energy model. Utility bills allow the energy modeler to calibrate the total energy consumption and the breakdown by fuel type, which is important to track as different fuel sources have different greenhouse gas emissions and associated energy costs.    

BMS Information - The BMS may be a source for a wide variety of operational data such as:   

  • Fan run hours   
  • Damper and valve positions   
  • Air and water flow rates    
  • Air handling unit supply air set points    
  • Space temperature set points   
  • Air, water and space temperatures   
  • Chiller/cooling tower/boiler entering and leaving water temperatures   
  • Pump flows during peak and off-peak times   
  • Fan and pump electrical consumption and demand data from VFDs 

The main parameters to collect are:  

  • Meter data  
  • Equipment hours of operation  
  • Temperature setpoints  
  • Data trends  
  • Fault detection  
  • System mode (manual versus override)

Historical data from the BMS can help align modeled energy use breakdowns with actual operation. Collating and reviewing this data can provide insights into building operations. Sometimes building operation differs from the document design, standards, and even the facilities team’s own understanding as system modifications are made incrementally over the years. Live data can be used to verify system schedules, turndown, and setpoints and drive even more accurate modeling of building operations. Building management systems provide insight into how the building is performing in real-time.  


Operator Interviews 

Information gathered from building operators can provide deep operation insights, serve to develop trust, and identify areas of opportunity for improvement. 

Existing Capital Plans 

It is also important to gather data on the “business as usual” (BAU) plan for future capital and operational expenditures.  Doing so allows the team to compare ECMs against already planned expenditures and to begin to understand the sequence and timing of ECMs within the context of already-planned building upgrades. 

Lease Turnover Schedules 

Having insight into lease turnover schedules can help define opportunities for engaging tenants in the low carbon retrofit process, and identifying proper phasing of decarbonization solutions in tenant spaces. 

Survey the Building: Understanding a building’s existing conditions requires time on-site. Design drawings, operator interviews, and utility data all provide valuable insight, but do not capture the nuances of ho