Building Performance Assessment Guide

Building Performance Assessment Guide

A Practical Framework for Facility Managers & Building Owners

Prepared by Zytona — Building Performance & Commissioning Specialists

Introduction: The Foundation of Building Improvement

Every meaningful building improvement initiative begins with the same question: Where do we stand today? Without a clear, data-driven understanding of current performance, facility managers and building owners operate in the dark—making decisions based on assumptions, vendor recommendations, or the loudest complaint rather than objective evidence.

Building performance assessment provides the diagnostic foundation that transforms reactive management into strategic investment. Consider the financial implications: buildings operating reactively typically spend 30–50% more on maintenance than those with proactive programs, according to research published by the National Institute of Building Sciences. Emergency repairs cost three to five times more than planned maintenance. Undetected energy waste compounds monthly, often representing 15–30% of utility costs in buildings that have never undergone systematic assessment.

Beyond cost, assessment reveals comfort problems before they drive tenant complaints, identifies code compliance gaps before they trigger violations, and documents equipment conditions before catastrophic failures disrupt operations. The assessment process itself creates accountability—establishing baselines against which future improvements can be measured and verified.

This guide provides a structured framework for conducting comprehensive building performance assessments. Whether you manage a single facility or a portfolio of properties, these protocols will help you identify opportunities, prioritize investments, and build the business case for improvement projects that deliver measurable results.

Section 1: Energy Performance Assessment

Establishing an Energy Baseline

Accurate energy assessment begins with data collection. Gather complete utility records covering a minimum of 12 months, though 24 months provides better insight into year-over-year patterns and helps distinguish anomalies from trends. Collect the following for each meter serving the building:

• Monthly consumption (kWh for electricity, therms or CCF for natural gas)
• Monthly demand (kW) for electric accounts
• Billing period dates (actual days in each billing cycle)
• Rate schedules and any demand ratchet clauses
• Interval data if available (typically 15-minute increments)

Request data directly from utilities when historical records are incomplete. Most utilities provide 24 months of history through online portals or upon written request.

Calculating Energy Use Intensity

Energy Use Intensity (EUI) normalizes consumption by building size, enabling comparison across facilities and against benchmarks. Calculate site EUI using this formula:

Site EUI = Total Annual Energy (kBtu) ÷ Gross Floor Area (square feet)

Convert electricity to kBtu by multiplying kWh by 3.412. Convert natural gas therms to kBtu by multiplying by 100. For reference, the Commercial Buildings Energy Consumption Survey (CBECS) published by the U.S. Energy Information Administration reports median site EUI values by building type: office buildings average 79.5 kBtu/sf, healthcare facilities average 192.2 kBtu/sf, and retail buildings average 52.6 kBtu/sf.

Energy Star Portfolio Manager Setup

Portfolio Manager, maintained by the U.S. Environmental Protection Agency, remains the industry standard for building energy benchmarking. Setup requires these steps:

1. Create an account at energystar.gov/portfoliomanager
2. Add property with accurate address and year built
3. Enter gross floor area measured to the exterior walls
4. Input property use details (operating hours, number of occupants, number of computers for offices)
5. Add meters for each utility type serving the property
6. Enter 12 months of consumption data for each meter
7. Generate an Energy Star score (1–100 scale, buildings scoring 75+ qualify for certification)

Key Metrics Beyond EUI

Peak Demand: The highest 15-minute average power draw during a billing period. High peak demand relative to average consumption suggests equipment simultaneously cycling, poor load sequencing, or demand spikes from specific processes.

Load Factor: Calculate as (Total kWh ÷ Hours in Period) ÷ Peak Demand. Values below 0.40 indicate poor load management. Values above 0.60 suggest efficient, consistent operation.

Demand Profile Shape: Interval data reveals whether consumption patterns match occupancy. Buildings showing flat 24-hour profiles despite scheduled occupancy have systems running unnecessarily during unoccupied periods.

Red Flags Indicating Performance Problems

• Site EUI exceeding benchmark median by more than 25%
• Rising EUI trend over consecutive years without operational changes
• Winter electric consumption approaching summer peaks (suggests electric reheat issues)
• Baseload (minimum nighttime/weekend consumption) exceeding 40% of peak-hour consumption
• Demand charges exceeding 30% of total electric bill
• Natural gas consumption during cooling season (unless process loads exist)

Interval Data Analysis

When interval data is available, analyze for these patterns:

• Morning Startup: Gradual ramp-up indicates proper soft-start sequencing; sharp spikes suggest simultaneous equipment starts
• Occupied Period Stability: Excessive cycling during occupied hours indicates hunting controls or oversized equipment
• Shutdown Pattern: Consumption should drop within 30–60 minutes after scheduled occupancy ends
• Weekend/Holiday Comparison: Consumption should drop significantly; minimal reduction indicates scheduling failures

Section 2: HVAC System Assessment

Equipment Inventory and Age Assessment

Begin with a complete inventory of HVAC equipment. For each major component, document:

• Equipment type, manufacturer, and model number
• Serial number and manufacture date (often encoded in serial number)
• Nameplate capacity (tons, CFM, MBH, HP)
• Original installation date
• Physical location and tag number
• Service history summary

Compare equipment age against median service life data published by ASHRAE. Chillers typically serve 20–25 years, rooftop units 15–20 years, boilers 25–35 years, and variable frequency drives 15–20 years. Equipment approaching or exceeding median life requires closer scrutiny and contingency planning.

Operational Data Review

Extract trends from the building automation system covering the past 6–12 months. Focus on:

Runtime Analysis: Compare actual equipment runtime against scheduled occupancy. Systems running 24/7 when scheduled for 12 hours indicate override conditions or scheduling errors. Calculate runtime percentage as (actual hours ÷ scheduled hours) × 100.

Setpoint Tracking: Plot actual temperature versus setpoint over time. Consistent deviation in one direction indicates capacity problems. Hunting around setpoint indicates control tuning issues.

Alarm History: Categorize alarms by system and frequency. Recurring alarms indicate unresolved underlying problems. High-priority alarms without documented response indicate maintenance gaps.

Field Observation Checklist

Physical inspection reveals conditions not captured by automated monitoring. Check these ten items during walkthrough:

1. Air Handler Coils: Check for fouling, biological growth, and fin damage. Dirty coils reduce capacity 20–40%.
2. Belt Condition: Inspect for cracking, glazing, and proper tension. Worn belts reduce airflow and efficiency.
3. Filter Condition: Note pressure drop across filters. Confirm filter type matches specification.
4. Ductwork Integrity: Check accessible ductwork for disconnected sections, open access doors, and damaged insulation.
5. VAV Box Operation: Verify damper movement when adjusting setpoint. Listen for hunting or chattering.
6. Thermostat Location: Confirm sensors are away from heat sources, exterior walls, and direct sunlight.
7. Condensate Drainage: Inspect drain pans and traps for standing water and biological growth.
8. Refrigerant Lines: Check insulation integrity and look for oil stains indicating leaks.
9. Equipment Nameplate Accessibility: Confirm all equipment can be identified for maintenance purposes.
10. Vibration and Noise: Note unusual sounds indicating bearing wear, imbalance, or component failure.

Testing and Balancing Status Review

Locate the most recent Testing, Adjusting, and Balancing (TAB) report. Confirm airflows and water flows match design requirements. Compare current conditions against documented values:

• Measure supply air temperature at diffusers in sample spaces
• Check fan speed settings against TAB report values
• Verify damper positions at terminal units
• For water systems, check pump differential pressure against design

Buildings without TAB documentation or those more than ten years since last balancing typically benefit from rebalancing services.

Controls and BAS Assessment

Evaluate the building automation system’s capability and utilization:

• Document BAS age, manufacturer, and software version
• Assess graphics completeness and usability
• Confirm trending capability and data retention period
• Check remote access functionality
• Inventory connected points versus standalone controls
• Evaluate sequence of operations documentation availability
• Test alarm notification functionality

Section 3: Indoor Air Quality Assessment

Parameters to Measure

Comprehensive indoor air quality assessment includes these parameters:

Carbon Dioxide (CO2): Primary indicator of ventilation adequacy. ASHRAE Standard 62.1 calculations typically result in indoor concentrations 500–700 ppm above outdoor levels when ventilation meets requirements. Concentrations exceeding 1,000 ppm above outdoor baseline suggest inadequate outdoor air delivery.

Temperature: ASHRAE Standard 55 defines comfort ranges. For typical office conditions with sedentary activity and standard clothing, acceptable operative temperatures range from 68°F to 76°F in winter and 73°F to 79°F in summer.

Relative Humidity: ASHRAE recommends maintaining below 65% to limit microbial growth. Levels below 30% cause discomfort and increase static electricity. Target range is 30–60%.

Carbon Monoxide (CO): Indicates combustion byproduct infiltration or parking garage air migration. Concentrations should remain below 9 ppm as an 8-hour average per EPA National Ambient Air Quality Standards.

Particulate Matter (PM2.5): Indicates filtration effectiveness and outdoor air quality. EPA recommends indoor levels below 12 µg/m³ annual average, with 35 µg/m³ as a 24-hour limit.

Total Volatile Organic Compounds (TVOCs): Indicates off-gassing from furnishings, cleaning products, and building materials. While no regulatory indoor standard exists, levels below 300 µg/m³ are generally considered acceptable.

Monitoring Equipment Options

Portable Instruments: Handheld multi-parameter monitors provide spot measurements during assessment. Advantages include lower cost, flexibility to measure multiple locations, and no installation requirements. Limitations include capturing only point-in-time conditions and requiring manual data recording.

Permanent Monitoring: Networked sensors provide continuous data, revealing patterns across occupancy cycles and seasons. Systems like those certified under the RESET Air standard provide verified accuracy. Installation costs are higher but ongoing operational insight justifies investment in spaces with documented IAQ concerns or high-value occupancy.

ASHRAE 62.1 Compliance Check

Review outdoor air delivery against ASHRAE 62.1-2022 requirements:

1. Determine space category and calculate required outdoor air rate using the Ventilation Rate Procedure
2. Verify outdoor air damper minimum position provides calculated requirement
3. Check demand-controlled ventilation CO2 setpoints against standard requirements
4. Confirm ventilation effectiveness factor is appropriate for air distribution method
5. Review system ventilation efficiency calculation for multiple-zone systems

Occupant Survey Methodology

Supplement measurement data with occupant perception surveys. The Center for the Built Environment at UC Berkeley provides validated survey instruments for this purpose. Key practices include:

• Survey timing should avoid periods immediately following complaints
• Anonymous responses increase candor
• Include questions about thermal comfort, air quality, lighting, and acoustics
• Ask about symptom frequency (headache, fatigue, eye irritation)
• Map responses by location to identify problem zones

Section 4: Commissioning Status Review

Documentation Audit

Comprehensive commissioning generates specific deliverables. Audit project records for these documents:

Owner’s Project Requirements (OPR): Defines the owner’s expectations for building performance, function, and operation. This document forms the basis for all commissioning verification.

Basis of Design (BOD): Documents how design decisions address OPR requirements. Links design intent to testable outcomes.

Commissioning Plan: Describes scope, schedule, roles, and specific testing procedures. Should include checklists for each system.

Commissioning Report: Documents all testing, results, and resolution of identified deficiencies. Should include functional test procedures with actual results annotated.

Buildings constructed to LEED certification requirements after 2005 should have these documents. Absence suggests either non-commissioned construction or poor record retention.

Functional Test Verification

Select representative systems and reverify commissioning test results:

1. Review original functional test procedures and documented results
2. Repeat key sequences (economizer changeover, staging, failure modes)
3. Compare current response against original documented performance
4. Note any sequences that have drifted from design intent

Performance drift is normal over time. Systems typically require recommissioning every three to five years to maintain original performance levels.