Recreational vehicles (RVs) typically use roof mounted air conditioning units, though there are a few different options that are commonly available. The two main categories of RV air conditioners are grouped according to whether or not they are ducted. Non-ducted RV air conditioners blow cold air into the motorhome or trailer directly from the unit, and ducted units send air throughout the interior space via channels in the roof or floor. Air conditioners that lack ducting typically have controls right on the unit, and the ducted variety often has a control panel that is located remotely. Another type of RV air conditioner combines both heating and cooling units in one roof mounted device.
The simplest RV air conditioners are non-ducted units. These air conditioners can be installed through a hole cut in the roof of the RV, though most units are designed to fit through preexisting roof vents. The air conditioning unit consists of a compressor, condenser, and blower that are all packaged together in an aerodynamic body that sits on the roof of the RV. A control unit is then bolted to the ceiling underneath the hole or vent, where it is connected to the roof unit. These RV air conditioners blow cold air directly from the control unit and usually have vents that can be opened or closed to direct air forwards or backward within the interior space.
Another common type of RV air conditioner is the ducted unit. Ducted RV air conditioners have the same type of aerodynamic package that bolts to the roof of the trailer or motorhome but lack a control unit on the ceiling inside. These air conditioners tend to offer more head room within the RV because there is no bulky control unit hanging down. Instead, the cool air is piped into a duct system that passes through the ceiling, walls, or floor of the RV. A recreational vehicle can have several of these air conditioners installed and may even have separate temperature zones that can all be controlled from a central panel.
Some RV air conditioners also come with an electric heating option. Most recreational vehicles burn liquid petroleum (LP) gas for heat, so a combination air conditioner and heater unit can provide an alternative when electricity is available. These units usually have a heating coil installed in the air conditioner. When the device is set to heat instead of cool, the element is warmed up and the blower motor forces air past it and into the RV.