Today’s Roof Air Conditioner Choices

June 22, 2008

Air conditioning is something that many of us have come to expect, whether it is in a house, car, office or RV. In many cases it is no longer an option as it once was. That is the case with most, if not all, motor homes and trailers today. While there are also manufacturers that mount the A/C units in the basement, we will only deal today with roof mounted. There are, and may be, configuration choices with options when it comes to ordering a new rig or replacement A/C unit. The selection may include the number of units, output capacity, heat strips, heat pumps, height profile, air ducted and possibly the thermostat control type. While many of these will probably not be a choice when purchasing a new rig, it is possible that a couple may, particularly if you are ordering a factory build. Let’s look at these choices.

Number of Units: Single A/C units are standard on Class “C” and “B” coaches, most trailers and shorter, entry level class “A” coaches. Larger class “A” coaches usually come standard with two units. The largest group of class “A’s”, 42′ to 45′, generally come standard with three A/C units.

In some cases, for those with only one unit, an additional unit can be ordered. This would apply to the class “A”, the trailers and possibly larger “C’s”. The “A” coaches equipped with two units may be able to specify a third A/C. Keep in mind, many of these upgrades may require changes to internal wiring and or, generator size, which may add considerably to the cost.

Output Capacity: There are several sizes, all rated in B.T.U. output, but the most popular being 13500 and 15000. Generally these require about 14.5 amps and 15.7 amps respectively, of AC power to operate. This however, can vary with different manufacturers. As the output is only about 11% difference, it is difficult to differentiate the two inside your coach.

Heat Strips: Are exactly what they sound like, they are heating elements within the A/C unit. Typically these provide about 5600 B.T.U.’s of heat when in use. These are not generally used on ducted A/C installations.

Heat Pumps: Heat pumps do not use heating elements. They basically reverse the A/C cycle exhausting the chilled air outside while warmed air is directed inside. These are very efficient and work well down to about 40 degrees F. outside temperature. Most heat pump set ups in today’s RV’s are wired to automatically switch to another heat source such as a furnace or HydroHot/Auqua Hot when outside temperatures warrant it. Likewise, they will re-start when the temperatures return to above 40 degrees F.

Height Profile: There are two common profiles, standard and low profile. The standard units project 12″ to 13″ above the roof, while the low profile is about 9″ high. Advantages are less wind resistance, can contribute to a lower overall vehicle height, and appearance.

Air Ducted: In most, if not all RV models, this is not a choice as it either comes that way or it does not. This is a good feature that can more evenly distribute the air throughout the coach.

Thermostat Selection: In some cases an optional remote thermostat can be purchased. This can provide the convenience of being able to set and monitor the temperature in any location within the coach. It may also provide a more precise control than that normally installed.

Anyway, that’s a brief simple version of what’s out there. Whether you are ordering a new recreational vehicle or replacing a worn out air conditioner, these are some of the choices and decisions you may have to make.

With More Cool Ideas – Lug_Nut