1. Pull your idle data
We work from your ELD or telematics idle reports (Samsara, Motive, Geotab, Omnitracs, or a simple fuel-card export). No new hardware.
Takes about 30 minutes
The Idle Bill · Fleet Idle Cost Campaign
Your Trucks Are Burning Fuel Standing Still.
A long-haul tractor burns about 0.8 gallons an hour at idle. At 6 hours a day and $5.60 diesel, that is roughly $9,542 per truck every year, and a Thermo King TriPac APU recovers about 69% of it. Build your fleet's Idle Bill below, then book a free idle audit to get the real number from your own data.
- Largest Thermo King Dealer in North America
- Free, No-Obligation Idle Audit
- TriPac APUs In Stock
Idle Cost Calculator
What is idling costing your fleet?
Start with your truck count and idle hours. Defaults follow U.S. DOE idle research and the current national diesel price; open Assumptions to use your own numbers.
Build Your Idle Bill
Sleeper rest, climate, hotel loads. Long-haul averages about 6.
$
DOE national average, week of Aug 31, 2026. Use your fleet card average.
Idle Bill
Annual · Estimate
- Fleet idle hours
- 100,110 hrs
- Diesel burned standing still
- 80,088 gal
- Diesel price
- $5.60 / gal
Amount you are paying to idle
$448,493
$9,542 per truck, every year.
With a TriPac APU
- APU fuel for the same hours
- $140,154
- Recoverable every year
- $308,339
- That is 69% of the bill · per truck
- $6,560 / yr
- Payback on a $13,000 install
- 24 months
- Five-year net, after buying the APUs
- $930,694
Estimate only. Fuel savings depend on your routes, climate, driver habits, and duty cycle. Default burn rates follow U.S. Department of Energy idle-reduction research (about 0.8 gal/hr idling) and Thermo King TriPac published consumption (about 0.25gal/hr). Payback excludes maintenance savings and engine-hour reduction, which typically improve the result. An Idle Audit replaces these assumptions with your fleet's own data.
0.8
Gallons burned per idle hour
2,130
Idle hours per truck, per year
69%
Less fuel with a TriPac APU
24 mo
Typical fuel-only payback
$4.48/hr idling vs $1.40/hr on APU
Thermo King TriPac APU
Cut the Idle Bill by About 69%.
A TriPac auxiliary power unit heats, cools, and powers the cab on about 0.25 gallons an hour instead of 0.8, so the main engine shuts off at the truck stop. Drivers keep the comfort; the fleet keeps the fuel, the engine hours, and the maintenance intervals.
About $6,560 back per truck, per year
Fuel alone, at 6 idle hours a day and $5.60 diesel. Higher idle or California diesel prices push it further.
Fuel-only payback around 24 months
On a $13,000 installed unit. Maintenance and engine-hour savings shorten it further.
Fewer engine hours, longer service intervals
Every idle hour is an engine hour. Shifting them to the APU protects the main engine, the DPF, and your resale value.
Idle-law ready
California and a growing list of states limit idling. Ask about CARB-compliant TriPac configurations for West Coast routes.
$448K
Idle bill, 47-truck fleet
$308K
Recoverable with TriPac
55,061
Gallons saved per year
Free Idle Audit
Stop Estimating. Get Your Real Idle Bill.
A Sonsray idle specialist builds your fleet-specific Idle Bill from your own telematics data, then shows exactly which trucks pay back fastest.
2. Build your Idle Bill
Idle hours by truck, gallons burned, dollars spent, and the recoverable share with a TriPac, using your fuel prices and routes.
Truck-by-truck breakdown
3. Get a payback plan
Which units to equip first, the APU configuration for your climate, install scheduling at a Sonsray location, and financing options.
Ranked by ROI
Fleet Idling Questions
What Idling Really Costs, Answered.
Figures use U.S. DOE and Argonne National Laboratory idle research, Thermo King published TriPac consumption, and the current DOE national diesel price. Run your own numbers in the calculator above.
How much does it cost to idle a semi truck?
About $4.48 an hour in fuel at $5.60 diesel, because a heavy-duty tractor burns roughly 0.8 gallons per hour at idle. A long-haul truck idling 6 hours a day, 355 days a year, spends about $9,542 on idle fuel alone, before engine wear and maintenance.
How much fuel does a truck burn while idling?
Roughly 0.8 gallons of diesel per hour, with published measurements ranging from about 0.6 to 1.0 depending on engine size, load, and whether the A/C or heater is running. At 6 hours a day that is about 1,704 gallons a year for one truck.
How much can an APU save a fleet?
A Thermo King TriPac runs on about 0.25 gallons an hour, so it cuts idle fuel by roughly 69%. That is about $6,560 per truck per year at current prices. For a 47-truck fleet, an Idle Bill of about $448,493 becomes roughly $308,339 recoverable every year.
Is a Thermo King TriPac worth it?
For a truck that idles 6 hours a day, yes: fuel savings alone repay a $13,000 installed TriPac in about 24 months, and the unit typically serves 7 to 10 years. Fewer main-engine hours, longer oil and DPF intervals, better driver retention, and compliance with state idle limits add to the return.
How many idle hours does it take to justify an APU?
Each idle hour moved to a TriPac saves about $3.08 in fuel at $5.60 diesel, so a $13,000 installed unit breaks even after roughly 4,221 idle hours. A truck idling 3 hours a day gets there in about 4.0 years; at 6 hours a day, about 24 months.
APU vs. idling: what is the cost difference?
Per hour of cab comfort: about $4.48 idling the main engine versus about $1.40 on a TriPac APU, at $5.60 diesel. Over a year at 6 hours a day, that is $9,542 versus $2,982 per truck.
How long does it take an APU to pay for itself?
About 24 months on fuel alone for a truck idling 6 hours a day, assuming a $13,000 installed cost and $5.60 diesel. Higher idle hours, higher fuel prices (California diesel runs well above the national average), and reduced maintenance all shorten the payback.
How do I reduce idle costs across my fleet?
Measure first: pull idle hours by truck from your ELD or telematics so you know where the fuel goes. Then set an idle policy, coach the high-idle drivers, and equip the trucks that idle most with an APU so the policy is livable in summer and winter. A free Sonsray Idle Audit does the measuring and ranks your trucks by payback.
Estimates for planning. An Idle Audit replaces them with your fleet’s own data.
Book an Idle AuditSonsray Fleet Services
Install and Service Near Your Routes.
TriPac installation, parts, and service at Thermo King dealer locations across the West Coast and the Northeast.
New Location
Existing Location
Book an Idle Audit
Find Out What Your Fleet Is Really Paying to Idle.
Tell us about your fleet and a Sonsray idle specialist will reach out to gather your idle data, build your Idle Bill, and walk you through the trucks that pay back fastest. Free, and no obligation to buy anything.
- Free idle audit from your own telematics data
- Largest Thermo King dealer in North America
- Response within 1 business day
- Your information is secure
Your Idle Bill
About $9,542 per truck, per year
Roughly $6,560 of it is recoverable with a TriPac APU. The audit tells you exactly how much for your fleet.