By Dave Millhouser

I couldnt get out of bed. Every time I sat up, dizziness overwhelmed me and I flopped back down.

My wife figured it out . . . dehydration caused by an overzealous bus demonstration the day before.

The customer had called to say hed be late and, crafty rascal that I am, it seemed like a good idea to let the demonstrator bake in the sun.

When the customer arrived I could show him one of these coaches best features -- its ability to cool down quickly.

The idea was good but the consequences werent.

So, dont try this at home. Leave me to do the stupid stuff and report the results so you dont hurt yourself. Think "test dummy."

Still, the idea wasnt entirely without merit.

We live in times when idling the engine to cool down a coach is verboten. Thats German for "no-no." In addition to laws limiting how long its allowed, idling wastes fuel and invites the dreaded "regen."

A coach that cools quickly is a good thing.

Some do better than others but the one common characteristic is that a well-maintained HVAC cools faster than a neglected one.

You know the drill . . . filters, motors, belts and Freon checked. Cleaning the condensers, ducts and return-air fixtures can significantly increase efficiency.

Another biggy is driver training.

Its important that drivers understand why idling needs to be limited, and how the HVAC works on the model of coach theyre driving. Each model of bus has unique characteristics that, if understood, can make them more efficient.

For example, at least one coach has an HVAC system with a "super-duper" blower speed that only works when its first switched on. Messing with the manual settings turns the speed down for the rest of the day.

There are a variety of ways to finagle the inside/outside air mix, and there can be adverse interaction between the drivers A/C and the cabin unit. Each model works differently and needs to operated accordingly.

Generally, transit buses have a single on/off HVAC switch, operating only in an automatic mode. Most motorcoaches offer automatic and manual modes, with automatic usually being the best setting. In certain circumstances a skilled driver may make the unit perform better.

A couple of other things could be discussed with drivers, in addition to teaching them how the system functions. Opening vents or windows is never a good idea (unless the HVAC has truly kicked the bucket). These systems love to recirculate air; each time they cool it a bit more. Adding outside air is rarely helpful.

When addressing passenger complaints about cabin temperature, drivers should make tiny adjustments to the temperature control. Modern systems are powerful, and too much finagling can lead to the dreaded "sine curve," where a cranky HVAC system takes revenge by becoming alternately too hot, then too cold, staying JUST ahead of the unwary driver inputs.

A fake adjustment from time to time might soothe both the passengers and the HVAC.

The sunny side will always be warmer than the "dark side," so drivers should make passengers aware of window shades -- if the coach has them. Weaving is NOT an acceptable method of making temperatures even.

Parking a waiting coach in the shade is an obvious idea, and popping windows and hatches can vent some heat. Drivers will want to be sure to secure the windows before moving the bus.

Once again, Ive been your test dummy on this, and apologize to whoever found the side glass that popped out of my bus on Interstate 5.

Its hard to come up with anything new on this topic. Thats because its so important that almost everything that can be said has been said.

What has changed a bit is the urgency.

The combination of 2010 and newer engines and their quirks, along with a growing number of anti-idling ordinances, has made HVAC maintenance more critical than ever. The refrigerants that dont expand the "Ozone Hole" are less efficient, exacerbating the problem.

In an era of instant gratification, we want to do the best we can to make sure our customers dont have to board a bus where the interior is so hot their spandex shrinks (or sticks to the seat covers). We old folks wilt easily.

Since running the A/C far in advance of boarding is not an option, it has become increasingly important that the HVAC be at peak operating efficiency; same for the charging system. Well-trained drivers can get the best performance out of the coach.

In case youre wondering, dehydration will NOT get you out of mowing the lawn at my house. Susan pumped me full of Gatorade, smacked me on the rump and aimed me towards the mower.

Dave Millhouser is a bus industry marketing consultant and freelance writer. Contact him by email at Davemillhouser@gmail.com.