So you’ve decided that your operation, one truck or a thousand, can’t afford the cost of endless idling, but what do you do about it? What do you buy? There are so many alternatives that you’re probably not quite sure where to turn.

At the Mid-America Trucking Show in Louisville, Ky. last March, for instance, a fellow journalist counted 43 different anti-idling tools on display, from small diesel-fired bunk heaters to full-bore auxiliary power units.

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. And if you pull refrigerated trailers, there are even a couple of systems that can run off the reefer’s diesel if need be.

The options seem to multiply monthly, so many that we’re not going to name names here for fear of offending those that don’t get mentioned. Your truck dealer can help, and in fact most truck-makers now have — or soon will — a ‘proprietary’ system of their own, most of them electric.

Each of the two major refrigeration specialists also offers auxiliary power units of their own, as does one engine maker and one Canadian engine distributor. Even a company best known for drive belts offers an APU, a unique one that can use its own two-cylinder diesel to run the truck’s standard alternator and AC compressor and other accessories. There’s no shortage of innovation here.

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 $1000 to well over $10,000. Basically, this is what’s on offer:

Shore power: You can spec or add shore-power connections easily enough, and then — if a connection can be found — run small appliances like stand-alone household air conditioners and heaters. Moves to ‘electrify’ truckstops have not been broadly successful, however.

— Start/stop engine timer: Programmed to start and stop the big engine automatically to maintain cold-startability, battery strength, or a pre-set sleeper temperature. Over $1000 to nearly $4000.

Powering an APU with a silent fuel cell, like
this one from Freightliner, makes long term sense.

— Diesel-fired bunk heater: The simplest and easiest solution if you don’t need cooling. It might list for something like $1200 and for about the same amount again you can add an engine heater.

If you figure idling at four hours a day for 35 weeks of the year to keep things cosy inside, a little bunk heater will sip fuel at the rate of about 0.25 litres an hour, compared to three litres an hour for that big Series 60 or whatever, and you’ll spend about $185 instead of $2400 on that fuel in a year. Four hours may be too few, of course, but even at that rate the heater is paid off in six months.

Both leading manufacturers of bunk heaters now offer cooling options as well, by the way.

— APU or genset: Auxiliary power units with their own diesel power have become the popular choice for fleets as well as owner-operators. More than a few fleet managers have plunked down a good bit of cash to retrofit 20, 50, or even 140 trucks in one case with APUs in the last year or so — at as much as $13,000 or so each, installed.

A genset, by the way, isn’t the same thing as an APU, though they’re similar, and one or the other may be a better solution for your needs than a small bunk heater.

If you or your drivers spend time in hot climates or pretty much live in the truck and want all the electrical pleasures of home, the advantages are real. Both consume about one eighth as much fuel as the truck’s big diesel, so there’s money to be saved and you’ll recoup the purchase cost within a year or a little more. A genset, or on-board generator, is simply a source of 110-volt AC power by way of a small one- or two-cylinder diesel engine.

An APU also uses a small diesel engine but goes a step further to run built-in climate-control systems while also heating the engine and charging the truck batteries. In 2008, emissions rules mean APUs will require diesel particulate traps like those on 2008-model trucks.

If heat is all you need a simple solution would be a small
diesel fired heater like this Espar unit paired with a coolant heater.

APUs come in two configurations: integrated, meaning they have their own AC compressor, condenser, and heat exchanger, and don’t need to tie into the truck’s system; and non-integrated, meaning they use the truck’s HVAC system and circulate coolant from the APU to provide heat, while running an AC compressor with help from the truck’s condenser and fans.

Among the things to watch for with a traditional APU is weight. Some are over 500 lb, routinely well above 300, though we know of one that tips the scales at just 220 lb. This may or may not be important to you. The other thing is installation cost. Some APUs — depending on how much frame-rail space they need — will be either expensive to fit or even impossible on trucks with elaborate side fairings. You want an APU with automatic low-battery-voltage protection and a shore power connection. You’ll pay anywhere from $7000 to $13,000 or more.

— Electric and other options: some truck-makers and other suppliers offer battery-based systems to provide heating, cooling, and 110-volt electrical power– usually for up to 10 hours — without running the big engine. By and large they’re cheaper than diesel-powered APUs, but make sure they offer the cooling capacity you need.

Typically, 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. A small diesel-fired heating unit completes the picture.

There are other variations on these themes, too many to list, and in the future we’ll see APUs powered by hydrogen fuel cells that emit nothing but water. For the last few years Freightliner has been developing one that’s fuelled by liquid hydrogen, and Modine, the radiator maker, has one too.

Neither will be ready for market until issues like cost, integration with other truck systems, and the availability of suitable fuel are resolved.

For now, it’s a safe bet that you’ll save fuel and money no matter which of the presently available systems you choose. Deciding what’s best for you may be somewhat complicated, but this is no-brainer territory. Really.