Every summer the same question shows up at truck stops and in the Facebook groups: should my next APU be electric? It’s a fair question. Battery-powered APUs have gotten better in the last few years, and the pitch is attractive. No second diesel engine on the truck, no fuel burned while you’re parked, no noise.
We build diesel APUs, so you know where we stand up front. Here’s the comparison the way we’d give it to a friend: what electric units genuinely do well, where they fall short of the promise, and how to tell which one fits the way you run.
What an electric APU actually is
An electric APU is a battery bank, an inverter, and an electric air conditioner. The batteries charge off your alternator while you drive, or off shore power where you can find it. Park, and the batteries run your A/C and your electronics, the TV, the microwave, the phone chargers, until they’re empty.
One thing worth knowing up front: in winter, most electric systems still lean on a fuel-fired bunk heater for real heat, because electric heat would flatten the batteries in a matter of hours. So “electric” mostly means electric cooling. The heat side usually burns diesel either way.
None of this is hypothetical. One of the better-known lithium systems prices its top package at about $12,000 installed, and its winter heat comes from a fuel-fired coolant heater that burns about a gallon of diesel every 10 hours. Even the factory battery HVAC option offered on some new trucks is rated for up to 10 hours of parked cooling.
Electric APU vs diesel APU at a glance
| Electric APU | Green APU diesel | |
|---|---|---|
| Runtime parked | 8 to 14 hours typical, less in extreme heat | As long as there’s fuel in the tank |
| Cooling output | 7,500 to 15,000 BTU on most units | 26,000 BTU |
| Winter heat | Usually a fuel-fired heater anyway | 26,000 BTU, built into the unit |
| Hot-cab pull-down | Pre-cooling with the main engine recommended | Pulls the cab down on its own |
| Multi-day sits | Limited by battery charge | No limit with fuel in the tank |
| Maintenance | Battery packs age and get replaced | PM every 1,000 hours with standard parts |
| Best fit | Home most nights, mild climate | Over the road, all seasons |
The rest of this article is the detail behind every row.
What electric does well
Credit where it’s due, because there’s real substance here:
- Silence. Nothing is running. If you’re a light sleeper, that matters.
- No second engine. No oil changes and no PM interval on the unit itself, though the winter heater and the charging system are still on the truck.
- Nothing burning while parked. No fuel use at idle, no emissions at the truck, and no-idle zones are a non-event.
That’s the pitch. The rest is what the brochure leaves out.
Where electric runs out
The battery is the fuel tank, and it’s a small one. Most electric units deliver somewhere between 8 and 14 hours of cooling on a full charge in decent conditions, and some newer lithium systems claim more. In brutal heat, less. That’s fine if you’re driving again in the morning. On a weekend sit or a 34-hour restart in July, it’s a different story, and the backup plan is usually idling the main engine, which is the exact thing you bought an APU to stop doing.
Here’s one that surprises people: most electric units are temperature maintainers, not temperature makers. The manufacturers themselves recommend pre-cooling the cab with the truck’s own A/C before you shut down, then letting the battery unit hold that temperature overnight. A 7,500 BTU system can keep a cool sleeper cool, but it can’t pull a 100-degree cab down quickly on its own. So on a hot day, the routine still starts with the main engine running.
Recharging takes drive time. The alternator needs hours of driving to refill what a hot night took out. Team operations and heavy electrical use make that math tighter. And the shore-power option on the brochure assumes a plug. Count the pedestals at the last five truck stops you parked at.
And batteries age. An electric unit is at its strongest the day it’s installed, and replacement packs some years down the road are a real bill. Ask any electric vendor what a new battery bank costs and when you should expect to need one. It’s a fair question and a good test of how straight they are with you.
If you’re picturing the electric unit as the light, simple option, weigh it first. On one leading all-electric system, the battery box alone comes in around 470 pounds before the evaporator and condenser go on. Batteries are the heaviest way anyone has ever stored a night of air conditioning.
Cold makes it worse. Lithium batteries lose capacity as the temperature drops, and most can’t take a charge below freezing until they’ve warmed themselves up, which is why the better systems build in battery heaters. So in January the unit spends energy keeping itself warm before it spends any keeping you warm, and the actual heat is still coming from a fuel-fired heater.
Output is the last piece. Most electric units cool somewhere in the 7,500 to 15,000 BTU range, and some of the best-known systems sit at the bottom of it. A big sleeper in a Texas August will work that hard.
Add it up and it explains what plenty of drivers learn the hard way: electric units promise big and deliver conditionally. On a hard night they can run out before morning, and they can’t run the sleeper the way a diesel unit can. When you’re on the road and the truck becomes your home, that matters.
What a diesel APU does well
A diesel APU measures its runtime in fuel, not charge. It will heat, cool, and power the sleeper as long as there’s diesel in the tank, whether that’s one night or four. It doesn’t care if the layover was planned, and it doesn’t ration your evening: run the A/C, the microwave, the TV, and the phone chargers at the same time, all night, with no battery math.
Ours puts out 26,000 BTU of heating and cooling, some of the highest output in the industry, and it charges your truck batteries while it runs instead of draining them. It refuels everywhere diesel is sold, which is everywhere you already go. And it pulls a hot cab down on its own. No pre-cooling ritual, no countdown.
The honest costs: it burns roughly a quarter gallon per hour, a fraction of what your main engine drinks at idle. It’s an engine, so it wants a service every 1,000 hours, and it makes some noise. Less than your main engine by a long way, but it isn’t silent.
One more thing that’s specific to how we build: our unit runs on standard automotive parts. Belts and filters come from any automotive parts store, and any diesel shop can work on it. That’s a maintenance story most APUs, diesel or electric, can’t tell.
The money side
On sticker price, electric can look friendly. Budget battery systems can land under $10,000 installed, while the premium name-brand electric units run into the same five-figure territory as a quality diesel APU. But the sticker isn’t what decides this. The nights are.
The math is worth seeing. At idle, a main engine burns about a gallon of diesel an hour. A diesel APU does the same job on roughly a quarter of that. For a truck idling around 3,200 hours a year, that works out to about 2,400 gallons saved annually, call it $9,000 at today’s prices, and the unit typically pays for itself in about 14 months. The math is in our cost breakdown, and you can run your own numbers on the savings calculator.
An electric unit saves a little more on the nights it can cover, because it burns nothing at all. The catch is the nights it can’t cover. Those turn into hours of idling the main engine, and a few of those nights a month quietly eat the difference.
Which one fits how you run
Electric makes sense if: you’re home most nights, your climate is mild, your sits are short and predictable, you have access to shore power, and silence is near the top of your list.
Diesel makes sense if: you’re over the road for weeks at a time, you take multi-day sits and 34-hour restarts, you run real summers and real winters, you’re part of a team operation, or you simply can’t schedule when you’ll need power.
One more angle if you run trucks for a living: fleet managers tend to value predictability over peak efficiency. A diesel APU behaves the same on every truck, every night, no matter how long the truck sits. One standard across the yard, and fewer surprise calls to dispatch.
The short version: the more nights you live in the truck, the more the math tilts diesel.
Where we land
We build diesel APUs because our customers live over the road, and a unit that runs out of power at 3 a.m. in a Laredo parking lot isn’t a comfort system, it’s a countdown timer. That’s been the design brief since 2011, when a fleet owner who ran about 200 trucks got tired of the options and built his own.
If you’re home every night, an electric unit might serve you fine, and we’d tell you so on the phone. If the truck is your home for weeks at a stretch, buy the one that never runs out before you do. See what ours costs, installed, or call 877-751-0686 and talk it through with the people who build it.
Specifications and prices for battery-powered systems referenced in this article come from manufacturers’ published materials as of July 2026.