HVAC Efficiency Self-Check: 25 Points for Facility Managers
Key takeaways
- Most checks need only bills, control-system trends and service records; five need a technician's readings.
- A flag tells you where to look, not what is wrong; trends over time matter more than single readings.
- 0–5 flags: fix the specifics. 6–10: schedule a focused diagnostic. 11 or more: quantify the loss and consider a measured pilot.
- Weight flags by equipment size, and start where flags cluster.
This self-check is for facility managers who suspect their cooling or refrigeration equipment is using more energy than it should, and want a structured way to find out before calling in vendors. It has 25 checks in five groups. The first two groups you can do yourself from bills and the control system. The third needs a technician's readings. The last two come from your records. Each item says what to check, what counts as a flag, and which guide explains the issue in depth.
Print this page, work through it over a week or two in warm weather, and count your flags. The scoring table at the end suggests what to do next. The self-check is a screening tool, not a diagnosis: a flag tells you where to look, not what is wrong.
Before you start: gather 24 months of utility bills, any interval meter data, building automation trend logs, two to three years of service tickets, and an equipment list. Have a technician scheduled for the readings in section 3; ask for actual numbers on every reading.
1. Bills and meters
Use 24 months of utility bills and, if you have it, interval (15-minute) meter data or building automation trends.
- Compare summer kWh year over year, adjusted for weather.
Flag if: summer consumption is up more than the change in cooling degree days explains, two years running, with no new load added.
Read: Why cooling costs keep rising - Look at the monthly peak demand (kW) on each summer bill.
Flag if: peak kW is creeping up from one summer to the next at similar occupancy and weather.
Read: Texas demand charges and 4CP - Check whether your account is billed on 4CP transmission charges (Texas, larger accounts) and what your 4CP demand was.
Flag if: nobody on staff knows whether 4CP applies, or 4CP demand is close to your annual peak, meaning cooling is running hard in the peak intervals.
Read: Texas demand charges and 4CP - Calculate energy use intensity (EUI) and, where eligible, an ENERGY STAR score.
Flag if: EUI is rising year to year, or the 1–100 score is well short of 75, the level a building needs to apply for ENERGY STAR certification.
Read: ENERGY STAR Portfolio Manager - Look at overnight and weekend electricity use.
Flag if: the base load outside occupied hours is high or rising, which often points to schedules overridden or equipment that never shuts off.
Read: Diagnosing efficiency loss
2. Run-time and comfort
Use building automation trends, thermostat logs or simply a week of observation in hot weather.
- Check compressor or unit run time on hot afternoons.
Flag if: units run continuously through the afternoon and still fall behind setpoint, where they used to cycle.
Read: Signs your HVAC is losing capacity - Track hot and cold calls from occupants or tenants.
Flag if: complaints are increasing, cluster in the late afternoon, or come from the same zones every summer.
Read: Signs your HVAC is losing capacity - Check indoor humidity in summer.
Flag if: spaces feel clammy, relative humidity stays high, or there are reports of condensation or musty odors.
Read: Signs your HVAC is losing capacity - Watch economizer dampers on a cool, dry day (where you have them).
Flag if: dampers do not move, are stuck open in hot weather, or the outdoor-air sensor reads wrong.
Read: Rooftop units - Review schedules and setpoints in the control system.
Flag if: schedules are overridden, setpoints differ from the written sequence, or there are many active alarms nobody is addressing.
Read: Diagnosing efficiency loss
3. Temperatures and pressures (with a technician)
These checks need a qualified technician with gauges or the chiller's own panel readings. Ask for the readings, not just a pass or fail, and write them down.
- Supply air temperature and the temperature drop across the cooling coil (delta T).
Flag if: supply air is warmer than it used to be at full load, or the drop across the coil is smaller than the design or the unit's history.
Read: How HVAC coils transfer heat - Superheat and subcooling, compared with the manufacturer's charging chart.
Flag if: either is outside the manufacturer's range, or charge has been "topped up" without these measurements.
Read: Diagnosing efficiency loss - Head (discharge) pressure and condensing temperature on a hot day.
Flag if: condensing temperature is well above outdoor temperature plus the manufacturer's expected difference, after the condenser coil has been cleaned.
Read: Does coil cleaning restore efficiency? - Chiller evaporator and condenser approach temperatures (chillers only).
Flag if: approach has risen over months or years compared with the commissioning or post-cleaning value.
Read: Water-cooled chillers - Measured kW/ton or kW at a known load, compared with the rating.
Flag if: measured efficiency is clearly worse than the nameplate or the unit's own earlier readings at similar conditions.
Read: kW/ton, EER and COP explained
4. Maintenance records
Pull the last two to three years of service tickets and the preventive maintenance schedule.
- Check how often filters are changed and what MERV rating is used.
Flag if: filters are changed on no fixed schedule, or are found loaded or bypassed at service visits.
Read: Commercial HVAC maintenance for efficiency - Check when condenser and evaporator coils were last cleaned, and what with.
Flag if: no record of cleaning in the last year, or coils were cleaned but performance did not recover.
Read: Does coil cleaning restore efficiency? - Count refrigerant additions over the past two years.
Flag if: refrigerant has been added more than once to the same system, or leak-rate calculations are not on file for larger systems.
Read: Why HVAC efficiency declines with age - Look for compressor issues: oil level problems, noisy starts, high discharge temperatures, replacements.
Flag if: a compressor has been replaced, or oil level, oil return or overheating has been noted more than once.
Read: Compressor wear and lubrication - Check whether each visit records readings (pressures, temperatures, amps), not just tasks.
Flag if: service tickets say "checked" or "OK" with no numbers, so you have no trend to compare against.
Read: Commercial HVAC maintenance for efficiency
5. Equipment age and refrigerant
Build or update a simple equipment list: unit, location, tonnage, year installed, refrigerant and oil type.
- Note the age of each major unit.
Flag if: units are past the middle of their expected service life and replacement is not yet budgeted.
Read: Repair, retrofit or replace - Note the refrigerant in each system.
Flag if: any system still runs on R-22, or nobody is sure what refrigerant some units contain.
Read: HFC phasedown and existing equipment - Check whether systems with 15 lb or more of HFC refrigerant are covered by federal leak repair rules.
Flag if: you do not know which systems are covered, or no leak-rate calculation is made when refrigerant is added.
Read: HFC phasedown and existing equipment - Note the compressor oil type (mineral, POE or PVE) and any past oil changes or additives.
Flag if: the oil type is unknown, or products of unknown composition (for example sealants) have been added to the system.
Read: Compatibility and safety - Check how long the system has run since installation without any internal (refrigerant-side) attention.
Flag if: a system has run for many years with rising run time and no explanation from external cleaning, charge or controls.
Read: What is oil fouling?
Why these checks
The checks follow the mechanisms most often found in field research. A 2004 ACEEE paper summarizing field studies of small packaged rooftop units reported that 46% failed a refrigerant charge screening test, about 70% moved 350 cubic feet per minute per ton of air or less against the roughly 400 that ratings assume, and 64% of economizers had failed. A 2022 study by Lawrence Berkeley National Laboratory and partners found a median of 245 faults per building per month in fault-detection data from air handlers and terminal units. ENERGY STAR notes that airflow problems alone can reduce efficiency by up to 15 percent. And laboratory research on evaporators has shown that oil retained inside the tubes adds pressure drop and reduces heat transfer capacity, a loss that external cleaning cannot reach. The HVAC energy use statistics page collects these figures with sources.
The self-check also leans on records, because trends need data. The DOE Federal Energy Management Program's operations and maintenance guide includes a sample chiller operations log for recording efficiency readings, and estimates that a good O&M program can save 5% to 20% of energy bills without significant capital investment. Many of the most useful flags are not single readings but changes over time.
Scoring: what your flags mean
| Flags | What it usually means | What to do next |
|---|---|---|
| 0–5 | Equipment is probably performing close to what you can expect for its age. Isolated flags are worth fixing but do not suggest a systemic problem. | Fix the specific items flagged. Make sure your maintenance contract records readings on every visit, and repeat this self-check each spring before cooling season. Review the maintenance-for-efficiency guide. |
| 6–10 | Several losses are probably stacking up. Expect a mix of maintenance, controls and charge issues, and possibly internal fouling on older systems. | Ask your service contractor for a diagnostic visit focused on the flagged units, using the method in diagnosing efficiency loss. Fix the low-cost items first (filters, coils, schedules, economizers, charge), then re-measure. Use the savings calculator to estimate what the remaining gap is worth. |
| 11 or more | Efficiency loss is likely significant and broad. On older equipment where cleaning and charge corrections have not restored performance, internal surfaces and compressor condition deserve attention. | Put numbers on the problem with the HVAC savings calculator, then consider a measured pilot on one to three representative units before committing to a larger project: request a pilot. Compare the options in repair, retrofit or replace. |
Weight the flags by the size of the equipment. One flag on a 500-ton chiller can matter more than five on a 3-ton split system. If most flags cluster on one unit or one plant, focus there first.
Where CryogenX4 fits
Several of the checks above (rising approach temperatures, longer run times that cleaning and charge corrections do not explain, years of operation with no refrigerant-side attention) point toward losses inside the heat exchangers. That is the problem CryogenX4 is designed for. According to the company, its one-time treatment is installed while the system runs, with no downtime, and lifts insulating oil film from internal coil surfaces, returning the oil to the compressor sump and improving the lubricity of the existing oil. CryogenX4 reports energy savings of up to 30%, with typical payback on the treatment of 12 to 36 months; results vary by equipment condition, so a measured pilot on your own units is the way to find out. The pilot program guide explains how one runs.
Next step: total your flags, note which units they cluster on, and bring this sheet to your next meeting with your service contractor, or to a pilot conversation with us.
Frequently asked questions
How long does the self-check take?
Gathering bills and records usually takes a few hours. The control-system checks take a week of observation in warm weather, and the technician readings can be added to a scheduled service visit.
Do I need a technician for every item?
No. Only the five temperature and pressure checks need a qualified technician with gauges or chiller panel access. The rest use bills, trends, service tickets and an equipment list.
Should I run it on every unit?
Start with the largest units and those with the most complaints. Bills and records apply to the whole building; readings are taken unit by unit.
What if I score 11 or more but the equipment is new?
On newer equipment, a high score usually points to installation, controls or charge problems rather than age-related wear. Ask the installing contractor to verify charge, airflow and control sequences against the design.
Sources
- Upstream Solutions to Downstream Problems: Improving Field Performance of Small Packaged HVAC Systems (2004) — ACEEE Summer Study
- What We Learned From Analyzing 18 Million Rows of Commercial Buildings' HVAC Fault Data (2022) — Lawrence Berkeley National Laboratory
- Heating and Cooling Maintenance Checklist — ENERGY STAR
- Operations & Maintenance Best Practices: A Guide to Achieving Operational Efficiency, Release 3.0 — U.S. DOE Federal Energy Management Program
- Experimental study of oil retention in microchannel type evaporators of air-source heat pump systems (2018) — International Journal of Refrigeration (via IIR FRIDOC)
- AIM Act Fact Sheet: Leak Repair Requirements for Appliances Containing HFCs (January 2026) — U.S. Environmental Protection Agency
- Phaseout of Class II Ozone-Depleting Substances — U.S. Environmental Protection Agency
- What is energy use intensity (EUI)? — ENERGY STAR
- Energy Savings Tips for Small Businesses: Grocery Stores (ENERGY STAR score and certification) — ENERGY STAR
Keep reading
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Read the guide →LearnWhy HVAC-R Efficiency Declines With Age
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Read the guide →See what your equipment could save
CryogenX4 is a one-time treatment installed while your system runs. Start with a pilot on a few units, measured against a baseline, before you commit to a building or a portfolio.