Although central air-conditioning units are inside a building, ductless units are usually located outside of a building. The location of ductless units prevents noise from being inside the homes. Rather than rely on a duct-and-vent system, small cooling units throughout the house connect to the outdoor main cooling unit. Ductless units are sometimes referred to as "mini-split" air conditioners. The small cooling units usually mount on a house's ceilings or walls. Some available ductless air conditions on the market are the Mitsubishi Mr. Slim M-Series units and the LG LS186CE.
Split inverter air conditioners are units with two sections. One section faces the outdoors, while the other faces within the household. The operation of this air conditioner is similar to window units or an automobile's system. However, split inverters are different than window air conditioners because their compressors are in the units' outside sections. This design also prevents excessive noise from entering the household. According to Gizmag, the LG Deluxe Split Inverter is one of the quietest air-conditioner models on the market. The LG Delux allows homeowners to place photos underneath the unit's transparent front panel.
Central air conditioners cool all areas of a building through a duct-and-vent system. Most central air units draw in outside air with fans located outside of the building. This prevents excessive noise from entering an office building or household. Another feature of central air conditioning allows the building's occupiers to create different temperatures in different rooms of the building. One of the quietest central air conditioners on the market is the Lennox HSX15. This unit relies on an insulated compressor compartment and direct-drive fan technology to prevent excessive noise from disturbing neighboring homes.
As its name implies, a rooftop air conditioner rests on top of a building's roof. Larger rooftop air-conditioner units typically are used for office buildings, but smaller models are available for RVs and households. Rooftop air conditioners are quiet because the noisy mechanical parts, such as the compressor and fan, are in the unit's outside section. The air from rooftop units enters buildings through vents positioned on ceilings throughout a building. Some rooftop air conditioners, such as Trane's Intellipak models, use evaporative-cooled condensers to reduce the amount of the unit's compressor usage, which in turn lowers the amount of noise the unit makes.