Among the obvious principles of successful trucking is the idea that those trucks of yours aren't earning a penny if they're not moving while there's freight onboard. Simple enough logic.

Equally simple is the notion that if their brawny diesels are idling at the same time, they're costing you a mighty big buck.

Zero idling is a complete impossibility, we understand, probably not even a useful target. If you're at a 25 percent idling rate you're already doing well, and a fancy $10,000 APU is unlikely to be of any use to you. Even then, there's work that can be done. But if you're at 50 percent idling or more, there's lots you can do.

Apart from the cost, there's the profusion of state and local laws that aim to limit idling. Despite calls to standardize these mandates across the country, even the continent, there's still no single rule. Nor does every jurisdiction have such a law in the first place - fewer than half the states limit idling right now. So it's a confusing picture at best, even if your routes are regular, because things change all the time. And there are cases where local authorities might have anti-idling rules in states that don't.

Both the Environmental Protection Agency and the American Transportation Research Institute maintain lists of idling regulations by state, county, and town or city, and the latter even offers a handy cab card. But are they absolutely up to date all the time? Nope.

What to do? One manufacturer of auxiliary power units probably has the right idea in suggesting you make a lowest-common-denominator assumption.

"Because of these wildly varying laws, it's best to adopt a best practice of say, no more than five minutes of idle time in the United States and no more than three minutes in Canada," they say.
The fines for non-compliance range as widely as the anti-idling regulations themselves, from a couple of hundred bucks to more than $10,000.

It's a bit wild and woolly out there in anti-idling land, to be honest, and answers to the challenge are very thick on the ground indeed. As the Environmental Protection Agency's SmartWay folks define things, there are five main option categories: fuel-fired heaters; battery-based HVAC systems; auxiliary power units; thermal storage systems; and shore power, in the unlikely event that your driver can find a plug.

We'll add a sixth and then a seventh option. The first is training and educating drivers to shut the diesel down whenever they can. The second is to back it up with an incentive program. The latter has been proven to work in some cases, but what about an Arizona summer or a Wisconsin winter? You might convince the troops to shut down when they wander into the truckstop for a burger, but you can't expect them to do without air conditioning or heat when the weather's extreme. If that's in a no-idle state, you have a problem.

So how do you resolve this one? There are so many alternatives within some of the five categories we listed that you're probably not quite sure where to turn. At the Mid-America Trucking Show a couple of years ago, a fellow journalist counted 43 different anti-idling tools on display, from small diesel-fired bunk heaters to full-bore auxiliary power units and the increasingly common electric HVAC systems. If you look at the EPA's current list of devices that would qualify for a federal excise-tax exemption, the number is more like 60, even allowing for a couple of outfits that have left the market. There are also at least two manufacturers we know of that have just entered the fray or soon will. It's very hard to keep up.

The options are so many that we're not going to name names here for fear of offending the 50 that wouldn't get mentioned. In addition, your truck dealer can help. In fact, most truck makers now have a proprietary system of their own, most of them electric.

What's common amongst all of them is that payback on your investment can be quick in theory, sometimes even within a year. After that, you're saving money on fuel - possibly thousands a year - and drivers no longer have to wear 16 pairs of long johns or strip down to their skivvies depending on the season.

Your choices depend, as always, on what sort of trucking you do and where you do it. It's a horses-for-courses sort of thing, and your options will cost anywhere from $1,000 to well over $10,000.

In general terms, this is what's available:

This is the simplest and easiest solution if you don't need cooling. It might list for around $1,200, cost a few hundred to install if you don't do it in your own shop, and for about the same amount again you can add an engine heater.

If you figure your trucks idle 10 hours a day for 35 weeks of the year to keep drivers warm, a little bunk heater will sip about 0.7 gal of fuel in that time, compared to eight or so for the truck engine. So you'll spend about $490 instead of $5,600 on that fuel in a year, assuming diesel at $4 a gallon. Ten hours and 35 weeks may be too many, of course, but at whatever rate, the heater is paid off very, very quickly.

Both leading manufacturers of bunk heaters now offer cooling options as well.

Increasingly common are battery-based heating/AC units that also provide "hotel" power to run microwaves and the like, never needing the truck's engine at all. If you pull a refrigerated trailer, there are even a couple of systems that can run off the reefer's diesel if need be. Typically these systems provide heating, cooling, and 110-volt power for up to 10 hours. By and large they're cheaper than diesel-powered APUs, but make sure they offer the cooling capacity you need.

While the truck is being driven, a beefed-up alternator of 185 amps or so charges a power pack consisting of deep-cycle batteries, and an electric air-conditioning compressor charges a thermal storage unit. When activated, an electric fan circulates cold air though the thermal storage unit and into the sleeper. Heat is usually supplied by a small diesel-fired unit.

By and large, they'll need about eight hours of charging - that is, running the truck and its alternator - before they're ready to go again, which may restrict their application. Most offer a shore power option.

These units are typically fairly light, but when you add the weight of three or four deep-cycle batteries, you'll be at or above the weight of an APU, about 400-plus pounds.

There are also smaller electric units that provide A/C only. Others offer just heat, including a newly introduced one for near-Arctic conditions. The A/C units will run on 110/115 volts off an APU, off a bank of on-board deep-cycle batteries, or off a shore power connection. The stand-alone electric heaters can be powered by an APU, shore power, or in some cases a 12-volt inverter.

Producing their own power by way of one-, two-, or sometimes three-cylinder diesel engines, APUs remain a fairly popular choice for fleets and owner-operators. That said, there are now more battery-based systems on offer than traditional APUs. Cost ranges from about $7,000 to $13,000 or so, installed. Some suppliers have financing options. At least one offers leasing.

If you spend time in hot climates or pretty much live in your truck and want all the electrical pleasures of home, the advantages are real. An APU may run its own integrated A/C compressor, condenser, and heat exchanger, and won't need to tie into the truck's system. Others use the truck's HVAC system and circulate coolant from the APU to provide heat, while running an A/C compressor with help from the truck's condenser and fans.

Some include a power inverter as standard equipment, some call it an option, and others don't offer one at all directly. However it happens, you'll obviously want plugs for the T