Comparing Electric & Diesel TRUs

For stationary and storage trailer applications, electric refrigerated trailer units (TRUs) cost roughly half as much to buy as diesel units and run at about a quarter of the operating cost. The trade-off is straightforward: electric TRUs only run while plugged in. If your trailers stay parked, electric wins on every line of the budget. If they move under load, diesel is still the right choice.

This article walks through the comparison in detail — purchase price, operating cost, performance, infrastructure, and noise — so you can decide which fits your operation.

Main Takeaways

Where electric clearly wins

~50% lower initial purchase price for comparable capacity
~75% lower energy cost per operating hour
~95% lower maintenance cost per operating hour
Zero on-site emissions and significantly lower noise output
No fuel procurement, delivery, or theft exposure

Where diesel still wins

Reefer operation while the trailer is in motion (over-the-road transport)
Sites without three-phase power available

Initial Investment

The purchase price gap between electric and diesel TRUs is wider than most operators realize. A typical swap saves $15,000–$25,000 on day one — before factoring in any operating cost differences or available incentive programs.

	Electric TRU	Diesel TRU
Purchase price	$15,000–$25,000	~$40,000
Installation	< $1,000	< $2,000
Shipping (North America)	< $1,000	< $1,000
Total typical project cost	$17,000–$27,000	~$43,000

Operating costs

This is where the gap compounds over the life of the equipment. For a unit running 2,000 hours per year, the combined energy and maintenance savings typically land between $7,000 and $11,000 annually. Beyond that, the indirect cost reduction — eliminating fuel vendors, fueling routes, and reactive repair work — is the savings your operations team will actually feel every week.

Cost category	Electric TRU	Diesel TRU	Electric advantage
Energy / fuel	$0.70–$2.10 / hour	~$4.00 / hour	~75% lower
Maintenance	~$0.20 / hour	~$2.00 / hour	~95% lower
Indirect / admin	Minimal	Substantial (fuel logistics, downtime, repair coordination)	Significant

See your own numbers: Use our ROI calculator

Performance and reliability

Electric and diesel TRUs are functionally equivalent at the work they’re designed to do. Both maintain set points from -20°F to +80°F in standard 53′ refrigerated semi trailers, and both have proven track records in commercial cold storage applications.

Reliability is comparable to a diesel TRU under five years old, and meaningfully better than older diesel units. The reason is mechanical: electric TRUs have one moving wear component (the drive belt connecting the electric motor to the evaporator fan), while diesel TRUs have an entire internal combustion engine to maintain.

The one real difference: electric TRUs only operate while connected to shore power. They are purpose-built for stationary, storage, and yard applications — not over-the-road transport.

Infrastructure requirements

Electric TRUs run on standard commercial three-phase power. Most distribution centers, cold storage facilities, and industrial yards already have what’s needed; sites without three-phase service will need to scope an electrical upgrade as part of the project. Diesel TRUs use existing fueling infrastructure — readily available, but increasingly subject to surcharges, restricted-access zones, and emissions reporting requirements in major metropolitan markets.

Specification	Requirement
Power type	3-phase, 50–60 Hz
ER-230 voltage	220–240V, dedicated 60-amp circuit
ER-460 voltage	440–480V, dedicated 30-amp circuit

Noise output

Electric TRUs operate around the high 60s in decibels. Diesel TRUs measure in the mid 80s. That’s roughly the difference between a household dishwasher and a gas-powered lawnmower.

The character of the sound matters as much as the volume. Diesel TRUs produce low-frequency engine noise that travels long distances and carries through building walls. Electric TRUs produce higher-frequency airflow noise from the evaporator fan — narrower in spectrum, more easily attenuated, and far less disruptive in mixed-use areas, near residential zones, or inside warehouses where workers are nearby.

For facilities operating extended hours or located in noise-restricted municipalities, the difference is the difference between operating freely and operating on a curfew.

Summary Comparison

Category	Electric Reefer Units	Diesel Reefer Units
Operating Costs	Lower energy costs with electricity; reduced maintenance expenses.	Higher energy costs from fuel; subject to diesel price fluctuations; more frequent maintenance required.
Environmental Impact	Zero direct emissions; quieter operation; meets stringent urban regulations; eligible for green incentives	Direct CO₂ and particulate emissions; stricter regulations in urban areas; limited access to clean air zones
Performance & Reliability	Consistent cooling performance; precise temperature control. Usable only for stationary trailers.	Proven reliability in extreme conditions; well-established technology. Ability to perform while trailer is moving.
Maintenance Requirements	Fewer moving parts; less frequent service intervals; lower long-term maintenance costs	Regular oil changes and filter replacements; more complex mechanical systems; higher maintenance frequency
Infrastructure Needs	Uses existing grid and facility capacity. Requires planning for electrical capacity upgrades	Uses existing fueling infrastructure; readily available diesel stations; minimal facility modifications
Operating Expense	Lower upfront purchase price; potential tax credits and rebates; lower TCO over equipment lifetime	Higher initial purchase cost; established financing options; no special incentives

Is electric right for your operation?

If your trailers stay on-site — for storage, staging, dock-side cooling, or as overflow capacity — electric TRUs are almost certainly the better economic choice. If your reefer operation requires temperature control while the trailer is moving, diesel remains the right tool.

For the stationary use case, the next step is matching the right unit to your trailer count, voltage, and temperature requirements.