Case study · Detailed Energy Survey
A mid-1980s ambient distribution facility on a 1.5-shift schedule with $58,000 in annual utility costs. Five targeted ECMs — LED high-bay, dock seals, destratification, HVAC scheduling, and motor VFDs — covered 24% of the bill with a 2.7-year blended payback.
Facility size
120,000 sf
Ambient, single tenant
Operations
1.5 shift
6 days/week, 5am–11pm
Annual savings
$14,200
24% utility cost reduction
Blended payback
2.7 yr
$38k project cost, 5 ECMs
A 120,000 sf regional distribution warehouse in central Illinois — pre-cast concrete tilt-up walls, built 1986, expanded once in 2003. Ambient storage (no cold rooms), 22 ft eave height with structural mezzanine over the office area. Eight dock positions on the south face, all in regular use through the work week.
Usage pattern
1.5 shifts, 5am–11pm Monday–Saturday; building largely vacant overnight and Sunday. HVAC and high-bay lighting have been running 24/7 since installation.
Existing systems
Four 25-ton RTUs (1986/2003), gas-fired unit heaters in the warehouse bay, 65% T8 fluorescent + 35% original metal-halide high-bay (mostly burned-out, supplemented by portable LED towers).
Annual utility cost
$58,400 — $45,200 electric (377 MWh) + $13,200 natural gas (14.9 k therms). Peak demand 108 kW. Blended electric rate $0.120/kWh.
Operations staffing
One operations manager, no dedicated facilities engineer. Maintenance vendor handles HVAC service quarterly. Reports to a regional VP who approves capital ≤ $50k without escalation.
Warehouses lose energy in patterns very different from offices: dock infiltration, lighting that doesn't match the actual work zones, and HVAC running through unoccupied night hours. The interval data and walk-through together identified all three.
High-bay lighting was original
Metal-halide fixtures from 1986, with about a third burned out. Floor lux readings were below OSHA recommended for materials handling, and forklift operators had been supplementing with portable LED towers — an unsafe workaround that also drew compressed-air-style standby load.
Dock seals leaked badly
All eight dock positions had worn or torn seals. Thermal imaging showed clear infiltration paths around the perimeter of each door — meaningful both in winter heating loss and summer cooling load.
HVAC ran 24/7, building used 18/6
The RTUs and unit heaters had been on a single 'always on' setpoint since installation. The building is dark Sunday and overnight every weekday. No optimal start, no setback, no holiday calendar.
Ranked by payback. The first two — HVAC scheduling and dock seals — produce most of the savings and are eligible for both Ameren Illinois prescriptive rebates and a custom incentive on the dock work.
| Measure | Annual savings | Project cost | Payback |
|---|---|---|---|
HVAC scheduling + setback 5am–11pm Mon–Sat occupied; 60°F heat / 82°F cool unoccupied | $3,800 | $0 | Immediate |
Dock seal replacement (8 doors) Foam-filled seals sized to truck fleet; vehicle restraints not in scope | $2,100 | $5,600 | 2.7 yr |
LED high-bay retrofit 48 metal-halide replaced with DLC LED 18,000 lm, 4000K, controls-ready | $5,400 | $18,400 | 3.4 yr |
Destratification fans (warehouse bay) 6 HVLS fans, 16 ft diameter, BACnet integration with RTU schedules | $1,900 | $8,200 | 4.3 yr |
Motor VFD on supply fans (4 RTUs) VFDs sized to 5 HP motors, NEMA 1 enclosure, bypass contactors | $1,000 | $5,800 | 5.8 yr |
| TOTAL | $14,200 | $38,000 | 2.7 yr blended |
Pre-rebate. Ameren Illinois Energy Efficiency Program prescriptive incentives reduce project cost by an estimated $7,400 (LED fixture + VFD), and the dock work qualifies for a custom incentive of $0.10–$0.15/kWh saved.
Phase 1 (Quick wins)
$3,800/yr
HVAC schedule + setback. Zero capital. Implemented by maintenance vendor at next quarterly visit.
Phase 2 (Capital, 90 days)
$2,100/yr
Dock seal replacement during scheduled Q4 shutdown. Ameren custom rebate filed pre-construction.
Phase 3 (Capital, next FY)
$8,300/yr
LED high-bay + HVLS fans + VFDs. Bundled for one bid cycle. Prescriptive rebates handled by trade ally contractor.
The regional VP approved Phase 1 and Phase 2 within the same quarter from the audit report. Phase 3 was bundled into next fiscal year's facilities capital request, with the trade-ally contractor selected through standard procurement.
Start with the free 60-second Self Audit. If the savings range looks meaningful, we'll talk about a paid Walk-Through Audit ($1,500–$3,500 for a warehouse this size) or a Detailed Energy Survey ($4,500–$12,000) depending on the depth you need for capital approval.
Names and specific identifying details in this case study have been altered to protect client privacy.