Our energy bills are too high. How does a Facilities Manager conduct an energy audit of a commercial building?

Set a specific objective, such as:

"Determine why annual energy costs have increased and identify measures capable of reducing utility costs by 10–20%, while maintaining occupant comfort." That gives you something against which to evaluate recommendations.

2. Collect 12–36 months of utility data

Gather electricity, natural gas, district steam/chilled water, and other fuel bills. ASHRAE recommends reviewing more than one year and preferably three years of utility history.ASHRAE Handbook

Create a spreadsheet with:

Look for:

• Rising consumption
• Unusually high summer/winter consumption
• High demand charges
• Large baseloads overnight
• Unexpected consumption during weekends
• Sudden changes after equipment or control modifications
• Utility rate changes versus actual increases in usage

Don't assume that a higher bill means the building used more energy. Rates, demand charges and weather can substantially affect the bill.

ENERGY STAR's Portfolio Manager can benchmark the building against its own historical performance and comparable buildings, including weather-normalized metrics.ENERGY STAR+1

energystar.gov

3. Calculate your baseline

At minimum, calculate:

Energy Use Intensity (EUI)

EUI=annual energy usebuilding floor areaEUI=\frac{\text{annual energy use}}{\text{building floor area}}

For example:

2,000,000 kWh/year ÷ 100,000 ft² = 20 kWh/ft²-year For a more complete comparison, look at source EUI as well as site energy. ENERGY STAR notes that source energy accounts for energy losses associated with generation, transmission and distribution.ENERGY STAR

Also calculate:

• Annual energy cost/ft²
• Monthly kWh/ft²
• Monthly therms/ft²
• Peak electrical demand
• Cost per kWh
• Cost per therm
• After-hours energy consumption
• Energy consumption per occupied hour, where useful

This gives you the baseline against which savings will be measured.

4. Walk the building with the operating staff

This is where the audit becomes useful.

Do the walk-through with the people who operate the building, rather than simply looking at equipment yourself. ASHRAE specifically identifies the operator's involvement as part of the walk-through process.ASHRAE Handbook

Inspect:

HVAC

Check:

• Supply/return-air temperatures
• Heating and cooling setpoints
• Schedules
• Simultaneous heating and cooling
• Economizer operation
• Outside-air quantities
• VAV operation
• Dirty filters/coils
• Damper operation
• Fan speeds
• Static-pressure setpoints
• Boiler/chiller staging
• Pump operation
• Boiler/chiller temperatures
• Short cycling
• Equipment running when the building is unoccupied

HVAC is often the first place I'd investigate in a commercial building with unexpectedly high consumption.

Building automation system

If you have a BAS, don't just verify that it's "working."

Look at actual trends:

• Zone temperatures
• Supply-air temperature
• Heating/cooling valve positions
• Fan speeds
• Equipment status
• Outside-air temperature
• Occupancy schedules
• Chilled-water/heating-water temperatures
• Alarms
• Night/weekend operation

A BAS can reveal problems that aren't obvious during a daytime inspection.

For example, a rooftop unit that appears perfectly normal at 10 a.m. may be heating the building at 2 a.m. every night.

Lighting

Inventory:

• Fixture type
• Lamp/wattage
• Number of fixtures
• Occupancy sensors
• Daylight controls
• Exterior lighting controls
• Operating schedules

Then physically inspect offices, corridors, restrooms, warehouses, parking areas and exterior lighting.

Look for lights operating:

• After hours
• In vacant spaces
• When adequate daylight is available
• At unnecessarily high illumination levels

Plug and process loads

Inventory significant loads such as:

• Computers/monitors
• Servers
• Copiers/printers
• Refrigeration
• Kitchen equipment
• Pumps
• Compressors
• Manufacturing equipment
• Battery chargers
• Space heaters
• Vending machines

Don't overlook "small" equipment operating continuously. Hundreds of watts running 24/7 become thousands of kWh per year.

Building envelope

Inspect:

• Roof
• Windows
• Exterior doors
• Weatherstripping
• Air leakage
• Insulation
• Loading docks
• Vestibules
• Solar exposure
• Shading

Use an infrared camera where appropriate to investigate suspected insulation or envelope problems, ideally under suitable temperature conditions.

5. Measure instead of guessing

Utility bills tell you how much energy the building consumed. Measurements help determine why.

Depending on the building, use:

• Clamp-on power meters
• Portable electrical submeters
• Temperature/humidity loggers
• Differential-pressure gauges
• Airflow measurements
• Light meters
• Infrared cameras
• Ultrasonic leak detectors
• BAS trend data
• Equipment runtime data

For example, if you discover that a 50-hp motor is running continuously when it should be intermittent, measure its actual operating pattern rather than estimating it.

The goal is to develop an energy balance:

Utility consumption → major systems → end uses → identified losses DOE emphasizes using consistent performance metrics and matching data collection to the questions the audit is intended to answer.The Department of Energy's Energy.gov

6. Break the building's energy use into major end uses

Build a rough estimate such as:

The exact numbers don't have to be perfect initially.

The important question is:

Where are the largest energy flows and where is energy being wasted?

ASHRAE's Level II methodology calls for a more detailed breakdown of energy use along with savings and cost analysis for practical measures.ASHRAE Handbook

7. Identify Energy Conservation Measures

Separate findings into three categories.

No/low-cost operational measures

Examples:

• Correct HVAC schedules
• Reset temperature setpoints
• Eliminate simultaneous heating/cooling
• Optimize boiler/chiller sequencing
• Reduce excessive outside air where permitted
• Correct economizer operation
• Turn off unnecessary equipment
• Adjust lighting schedules
• Enable occupancy sensors
• Correct BAS programming
• Reduce excessive static pressure
• Repair leaking compressed-air systems

These are often the first things to implement because they require little capital.

Moderate-capital measures

Examples:

• LED lighting
• Variable-frequency drives
• Controls upgrades
• High-efficiency motors
• HVAC equipment replacement
• Pump optimization
• Boiler controls
• Chiller optimization
• Improved insulation
• Air sealing

Major capital projects

Examples:

• Chiller replacement
• Boiler replacement
• Major HVAC replacement
• Building-envelope upgrades
• Heat-pump conversion
• Central plant redesign
• On-site generation

These require substantially more engineering and financial analysis.

8. Quantify every recommendation

Don't report:

"Replace the lighting with LEDs." Report something closer to:

LED retrofit Existing load: 150 kW Proposed load: 80 kW Operating hours: 4,000/year Estimated savings: 280,000 kWh/year Electricity cost: $0.12/kWh Estimated annual savings: $33,600 Project cost: $85,000 Simple payback: 2.5 years The basic calculations are:

AnnualSavings=EnergySavings×EnergyRateAnnual\ Savings = Energy\ Savings \times Energy\ Rate

and

SimplePayback=ProjectCostAnnualSavingsSimple\ Payback = \frac{Project\ Cost}{Annual\ Savings}

For more substantial projects, go beyond simple payback and calculate lifecycle economics, maintenance savings, incentives, financing costs and expected equipment life.

9. Don't forget the utility rate structure

This is an especially important Facilities Manager issue.

Two buildings can consume the same number of kWh but have very different bills.

Examine:

• Energy charges
• Demand charges
• Time-of-use rates
• Ratchets
• Fixed charges
• Power factor charges
• Gas demand/transportation charges
• Available rate alternatives

For electricity, determine when the building hits its peak kW.

If a building has a large demand charge, reducing a handful of short-duration peaks can sometimes produce substantial savings without reducing annual kWh by the same percentage. ENERGY STAR specifically tracks electric demand separately from electricity consumption.ENERGY STAR

10. Rank the opportunities

I would put every measure into a table like this:

Don't evaluate projects on payback alone. Also consider:

• Reliability
• Maintenance
• Equipment end-of-life
• Comfort
• Safety
• Capital availability
• Disruption to occupants
• Incentives/rebates
• Remaining useful life
• Interaction between projects

For example, don't replace a chiller this year if a controls optimization could substantially reduce the required chiller capacity and should be done first.

11. Create an audit report

A good Facilities Manager's report should allow the owner to make decisions without rereading the entire audit.

I'd structure it as:

1. Executive summary
2. Building description
3. Utility-cost history
4. Energy-use baseline/EUI
5. Benchmarking results
6. HVAC findings
7. Lighting findings
8. Controls/BAS findings
9. Building-envelope findings
10. Plug/process-load findings
11. Utility-rate analysis
12. Energy conservation measures
13. Cost and savings calculations
14. Recommended implementation sequence
15. Measurement & verification plan
16. Appendices with equipment inventories and measurements

ASHRAE specifically calls for recommendations to state their assumptions and savings, prioritize practical modifications, and recommend measurement/verification methods.ASHRAE Handbook

12. Verify that the savings actually happened

This is the step that often gets skipped.

After implementation, continue tracking:

• Monthly kWh
• Peak kW
• Gas consumption
• Weather
• Occupancy
• Operating hours
• Equipment runtime

Then compare actual performance with the baseline.

For example:

Baseline: 2.0 million kWh/year After controls optimization: 1.72 million kWh/year Weather/occupancy-adjusted savings: approximately 280,000 kWh/year That turns an energy audit from a one-time report into an energy-management program.

A good Facilities Manager workflow

In practice, I'd use this sequence:

Bills → Benchmark → Walk-through → Measure → Find causes → Calculate savings → Prioritize → Implement → Verify

For an existing commercial building, I'd generally start with a Level I walk-through and utility analysis, then move to a Level II audit if the initial findings justify deeper investigation. ASHRAE identifies Level III as the appropriate level when detailed engineering analysis is needed for major capital decisions.ASHRAE+1

If your bills are currently much higher than normal, the fastest first pass is to examine the last 24–36 months of bills, identify the largest change in kWh, therms, peak kW, and operating pattern, and then correlate that change with HVAC schedules, BAS trends, occupancy, weather, and utility rates. That often points you toward the problem before you spend money on a full audit.

• Monthly kWh
• Peak kW
• Gas consumption
• Weather
• Occupancy
• Operating hours
• Equipment runtime

Then compare actual performance with the baseline.

10. Rank the opportunities

I would put every measure into a table like this:

1. Collect 12–36 months of utility bills—electricity, gas, fuel, water—and calculate annual energy use, cost, demand, and EUI (kBtu/ft²-year).ASHRAE Handbook Online
2. Benchmark the building against similar buildings using ENERGY STAR Portfolio Manager or ASHRAE Building EQ.ASHRAE Government+1
3. Walk the facility with operators, documenting HVAC, lighting, controls, envelope, domestic hot water, refrigeration, elevators, plug loads, and operating schedules.
4. Look for obvious waste: simultaneous heating/cooling, excessive HVAC schedules, poor setpoints, leaking dampers, dirty filters/coils, inefficient lighting, unnecessary nighttime loads, and malfunctioning controls.
5. Measure where needed: temperatures, humidity, airflow, electrical loads, lighting levels, equipment runtime, and HVAC performance.
6. Identify energy-conservation measures (ECMs) and estimate each one's energy savings, installation cost, maintenance impact, and simple payback.
7. Prioritize measures into no/low-cost operational changes, moderate projects, and capital improvements.
8. Implement and verify savings by comparing post-project energy use against an appropriate baseline.

ASHRAE distinguishes Level 1 (walk-through), Level 2 (detailed energy survey/analysis), and Level 3 (detailed capital-project analysis); Level 2 is generally appropriate when you need investment-quality recommendations.ASHRAE Government+1

A good audit should end with a prioritized action plan—not just a list of equipment problems.ASHRAE Handbook Online

Here is how a facilities manager tackles an energy audit step-by-step:

1. Data Collection and Benchmarking

• Utility data: Gather at least 12 to 36 months of utility bills (electricity, gas, water, steam) to analyze historical consumption, peak demand charges, and seasonal trends.
• Benchmarking: Enter the data into a tracking tool like the EPA ENERGY STAR Portfolio Manager to see how the building compares to similar properties nationwide.
• Operational schedules: Document building occupancy hours, thermostat setpoints, and equipment runtimes.

1. Preliminary Walkthrough (ASHRAE Level 1)

• Visual inspection: Walk through the entire facility to check for obvious inefficiencies, such as uninsulated pipes, outdated lighting, blocked vents, or doors/windows left open or poorly sealed.
• Equipment inventory: Catalog major energy consumers including HVAC units, boilers, chillers, lighting types, and large office or industrial machinery.
• Employee interviews: Talk with building occupants and maintenance staff to identify hot/cold spots, drafty areas, or equipment that runs when it shouldn't.

1. Detailed Investigation and Data Gathering (ASHRAE Level 2)

• Sub-metering and logging: Install temporary data loggers on specific circuits or equipment to track runtime and power draws over several days or weeks.
• Thermography: Use an infrared thermal imaging camera to detect building envelope air leaks, missing insulation, or overheating electrical panels and mechanical bearings.
• Lighting and plug-load audits: Measure actual light levels (foot-candles) against standards and evaluate the energy draw from phantom or vampire loads (equipment drawing power in standby mode).

1. Energy Analysis and Calculations

• Energy modeling: Analyze the collected data to break down energy use by category (e.g., HVAC usually accounts for≈4 0%−5 0% of commercial use, lighting for≈2 0%−3 0%, and plug loads for the remainder).
• ECM identification: Develop a list of Energy Conservation Measures (ECMs), calculating the estimated implementation cost, annual energy savings, and simple Payback Period (𝑃=C o s t A n n u a l S a v i n g s).

1. Reporting and Implementation

• Audit report: Compile findings into a formal report prioritizing ECMs into low-cost/no-cost operational tweaks (e.g., rescheduling BMS timers) versus capital investments (e.g., upgrading to LED fixtures or replacing an aging centrifugal chiller).
• Execution and Monitoring: Implement the approved projects and continuously track post-installation utility data to verify that the projected Return on Investment (ROI) is actually achieved.

Would you like me to detail the low-cost/no-cost operational changes a facilities manager can implement immediately, or dive deeper into capital-intensive upgrades like building automation systems (BAS)?

Phase 1: Preparation and Data Collection (Benchmarking)

1. Gather Utility Data : Collect at least 24 to 36 months of electricity, gas, water, and fuel bills to establish seasonal baselines, peak demand charges, and rate structures.
2. Calculate Energy Use Intensity (EUI) : Divide total annual energy consumption (in kBtu) by the gross floor area (sq. ft.) to measure whole-building performance.kw-engineering.com+2
3. Benchmark the Property : Compare the building’s EUI against similar regional facilities using tools like the EPA ENERGY STAR Portfolio Manager to see how poorly or efficiently the building performs.

Phase 2: The On-Site Walk-Through (ASHRAE Level 1)

1. Interview Occupants and Staff : Talk with maintenance technicians, building engineers, and staff to identify uncomfortable zones, operational quirks, or equipment operating outside standard hours.environenergy.com+1
2. Inspect Major Systems : Audit the HVAC equipment (chillers, boilers, air handlers, thermostats), lighting types (LED vs. fluorescent), building envelope (windows, insulation, doors), and plug loads (office equipment, vending machines).
3. Identify Low-Cost / No-Cost Measures : Spot immediate fixes such as adjusting HVAC schedules, repairing faulty steam traps, fixing leaking seals, or turning off unnecessary lighting and equipment in empty zones.psc.wi.gov+1

Phase 3: Detailed Investigation and Energy Calculations (ASHRAE Level 2)

1. Analyze End-Use Breakdown : Estimate energy consumption sub-totals for heating, cooling, ventilation, lighting, and domestic hot water.
2. Conduct Financial Analysis : Calculate project implementation costs, projected annual energy savings, simple payback periods, and Return on Investment (ROI) for identified Energy Conservation Measures (ECMs).kw-engineering.com+2
3. Prioritize Capital Improvements : Rank retrofit opportunities (like upgrading to variable frequency drives (VFDs) on pumps/fans, modernizing building automation systems (BAS), or replacing old chillers) by financial return.kw-engineering.com+2

Phase 4: Investment-Grade Analysis (ASHRAE Level 3 - Optional)

1. Perform Data Logging and Testing : Install temporary data loggers on critical equipment circuits to monitor runtime hours, electrical draws, and temperature fluctuations over several weeks.
2. Run Computer Simulations : Build dynamic thermal building models to test the impact of complex retrofits before spending capital.
3. Develop Final Master Plan : Produce an actionable capital improvement roadmap with firm contractor quotes to secure executive funding.kw-engineering.com+2

If you'd like, tell me:

• What is the primary building type (office, retail, warehouse, or healthcare)?
• What is the approximate square footage?

I can help you estimate which ASHRAE audit level fits your budget and goals.

The Three ASHRAE Audit Levels

• Level 1 (Walk-Through Analysis): Gathers historical utility data, benchmarks the building against similar facilities, and performs a visual walkthrough to identify low-cost or no-cost operational fixes.thergroupllc.com+3
• Level 2 (Energy Survey and Analysis): Provides a comprehensive facility survey, breaks down energy use by end-use system (HVAC, lighting, plug loads), analyzes utility rate structures, and provides detailed cost-benefit estimates for energy efficiency measures.environenergy.com+2
• Level 3 (Detailed Analysis of Capital-Intensive Modifications): Focuses on major capital projects by deploying intensive sub-metering, rigorous material testing, and precise computer modeling for complex mechanical systems.kw-engineering.com+2

Step-by-Step Execution Workflow

1. Data Collection and Benchmarking: Gather past 24 to 36 months of utility bills (electricity, gas, water, steam). Enter the data into platforms like the EPA ENERGY STAR Portfolio Manager to calculate your Energy Use Intensity (EUI) and compare performance against national averages.
2. Pre-Inspection Preparation: Review architectural and mechanical drawings, operations schedules, occupancy patterns, and sequence of operations for the Building Automation System (BAS).
3. Site Walkthrough and Inspection: Inspect the physical envelope (doors, windows, insulation), examine the nameplate data of HVAC units, boilers, and chillers, check lighting types (LED vs. fluorescent), and identify operational anomalies like simultaneous heating and cooling.
4. Data Analysis and Deficiency Identification: Correlate utility spikes with weather data and operating hours. Pinpoint primary culprits such as uncalibrated economizers, aging equipment, out-of-date lighting controls, or excessive after-hours phantom loads.
5. Developing the Energy Audit Report: Compile findings into a formal report outlining Recommended Energy Efficiency Measures (EEMs). Include estimated implementation costs, projected annual energy savings, simple payback periods, and return on investment (ROI) calculations.kw-engineering.com+1

If you'd like, tell me:

• What is the approximate square footage and primary use of your building (office, retail, warehouse)?
• Do you currently have a Building Automation System (BAS) installed?

I can help you prioritize which audit level makes the most sense for your budget.

1. Define the audit goals and scope

Before collecting data, establish what you are trying to accomplish:

• Reduce monthly utility costs
• Lower peak demand charges
• Improve occupant comfort
• Identify deferred maintenance issues
• Prepare for capital upgrades
• Meet sustainability or carbon goals

Decide whether you need:

• Level 1 audit: quick screening and low/no-cost savings opportunities
• Level 2 audit: detailed analysis with estimated savings, costs, and paybacks
• Level 3 audit: investment-grade analysis for major capital projectsEnergy Audit UCDavis

2. Collect building and energy data

Start at your desk before walking the building.

Gather:

Utility information

• 12–36 months of: - Electric bills (kWh, kW demand, rate structure)
• Natural gas/fuel bills
• Water and sewer bills (if relevant)
• Peak demand patterns
• Utility rate schedules and demand charges

Building information

• Square footage
• Building use and occupancy
• Operating hours
• Tenant schedules
• Floor plans
• Equipment lists
• Preventive maintenance records
• HVAC sequences of operation
• Building automation system (BAS) data

Calculate baseline metrics:

• Energy Use Intensity (EUI): annual energy use ÷ building square footage
• Energy cost per square foot
• Peak demand profile
• Seasonal consumption patterns

Benchmarking helps determine whether the building is actually inefficient compared with similar facilities.U.S. Green Building Council

3. Perform a building walk-through inspection

Walk the facility with maintenance staff and inspect the major energy systems.

HVAC systems (often the largest energy user)

Check:

• HVAC schedules (are systems running when spaces are empty?)
• Thermostat settings and overrides
• Economizer operation
• Chiller/boiler efficiency
• Air filter condition
• Simultaneous heating and cooling
• Outside air damper operation
• Variable frequency drives (VFDs)
• Duct leaks
• Refrigerant issues
• Preventive maintenance history

Common quick wins:

• Correct schedules
• Reset supply air temperatures
• Repair controls
• Tune equipment
• Improve maintenance practices

4. Audit lighting systems

Inspect:

• Fixture types (LED vs fluorescent/HID)
• Lighting schedules
• Occupancy sensors
• Daylight controls
• Exterior lighting controls
• Areas with lights running unnecessarily

Potential improvements:

• LED retrofits
• Occupancy sensors
• Automated scheduling
• Daylight harvesting

5. Evaluate the building envelope

Look for energy losses from the structure:

• Air leaks around doors/windows
• Poor insulation
• Roof issues
• Failed weather stripping
• Single-pane glazing
• Excess solar heat gain

Envelope problems often increase HVAC loads.

6. Review electrical loads and plug loads

Identify:

• Equipment running after hours
• Computers and monitors left on
• Kitchen equipment
• Data centers/IT closets
• Motors and pumps
• Vending machines
• Battery chargers

Consider:

• Smart power strips
• Equipment shutdown policies
• Load scheduling
• High-efficiency motors

7. Review the building automation system (BAS)

Many commercial buildings waste energy because controls are poorly configured.

Check:

• Time schedules
• Temperature setpoints
• Alarm history
• Sensor accuracy
• Trend data
• Simultaneous heating/cooling
• Demand control ventilation
• Night setback/setup settings

A well-tuned BAS can often produce savings without major equipment replacement.

8. Identify Energy Conservation Measures (ECMs)

Create a list of possible improvements and rank each one.

For every measure, document:

Include:

• Estimated energy reduction
• Installation cost
• Maintenance impact
• Comfort impact
• Expected life
• Available utility rebates

Audit reports typically prioritize measures by savings potential, implementation cost, and return on investment.studylib.net

9. Create an action plan

Separate recommendations into:

Immediate (0–90 days)

• Fix controls
• Adjust schedules
• Repair leaks
• Change operating procedures

Short term (3–18 months)

• Lighting upgrades
• BAS improvements
• HVAC tuning
• Motor upgrades

Capital projects

• Chiller/boiler replacement
• Envelope improvements
• Renewable energy
• Major mechanical upgrades

10. Verify savings after improvements

After implementing changes:

• Compare utility bills before and after
• Normalize for weather and occupancy changes
• Track kWh, therms, demand, and cost
• Confirm expected savings were achieved

A good audit is not just a report—it becomes an ongoing energy management program.

A practical first-week checklist for a Facilities Manager

1. Pull 24 months of utility bills.
2. Calculate EUI and monthly energy trends.
3. Review BAS schedules.
4. Inspect HVAC operation during occupied and unoccupied hours.
5. Walk every floor and record lighting/HVAC issues.
6. Identify the top 10 energy-saving opportunities.
7. Estimate cost, savings, and payback.
8. Implement no-cost fixes immediately.

For a commercial building with unexpectedly high bills, the fastest savings usually come from controls, HVAC scheduling, maintenance corrections, lighting, and demand management before pursuing expensive equipment replacements.teamenergy.com