Mini-split systems are able to dry some of the extra moisture during the warmer months. Unfortunately, they are not designed to dehumidify in cold climates and will not draw moisture out in the winter months. Dehumidification must be performed independently of cooling systems to ensure proper moisture removal. Along with heating and cooling, ductless mini-divisions can also dehumidify your home.
It is an essential part of the cooling process. However, you can also configure your system to only control humidity when needed. A mini split in dry mode works just like a dehumidifier, although it has the ability to take up more space than most dehumidifiers. However, a mini split will still emit some cool air as it is dehumidified, so it may not be a good option for extremely cold temperatures.
A minisplit without ducts works much like a traditional air conditioner. Air conditioning helps remove moisture from the air as it cools the indoor environment. It's like having a tiny dehumidifier in the system. Mini-divisions dehumidify and remove moisture from the air.
Most mini-divisions reduce the humidity level to around 45-55% relative humidity. Ductless minisplit systems can dehumidify to some extent, especially if your ductless minisplit has a dry mode. However, mini divisions are the ones that dehumidify the most in summer and least in winter. If you want to reduce the relative humidity of your home in the colder months, you will need a separate dehumidifier unit.
Both can effectively remove moisture from the air, but with key differences. A mini-split, set to dry mode, keeps releasing some cool air as it dehumidifies. Meanwhile, a dehumidifier only sucks in moist air to exhaust dry air. It is recommended to use a dehumidifier during the winter as it does not release cold air, it even increases the temperature by releasing hot and dry air.
Cold air retains less moisture than warm air, which means that a minisplit heat pump will dehumidify the air a little as it cools your home. Dehumidifiers are better at removing moisture, but some mini-splits have a “dry” mode, which provides similar dehumidification performance. Ventilation does not change the dew point of the air, no amount of ventilation will reduce the dew point of indoor air below that of incoming air. Humidity control uses lower fan speeds that remove moisture without the heat transfer part of the air conditioning process.
When hot, humid air enters the humidifier, it crosses the condenser coils that reduce the air temperature. Dehumidifiers work much like mini-splits, except that instead of cooling the air and then blowing it directly into the room to keep the living room cool, dehumidifiers have a final stage where the air is heated before it leaves the unit. Through that, the mini split continues to dehumidify and reduce air humidity, as well as cooling the air at the same time. Homes that have high humidity during the summer often leak, so sealing air leaks in your home's heat wrap will often help keep indoor air dry.
A fan in the air handler blows warm air from the room through the evaporator, causing it to cool. Many minisplit heat pumps have a “dry” mode, which reduces the fan speed in the air handler so that more moisture is removed from the air as it passes through the evaporator coil without cooling the room too much. Air moves through the dehumidifier at a much slower speed, allowing the unit to remove more moisture without cooling the air as much. If you live in a naturally humid area, you can use air conditioning or a dehumidifier to keep humidity within the recommended range.
When people think of air conditioning, they usually only think about the part where the system cools the air in their home. Cold air can hold less water vapor than warm air, so in addition to controlling the temperature, a mini-split helps dehumidify the air in your home when operating in cooling mode. Some dehumidifiers are installed directly into the air conditioning system and dehumidify the air as it passes through the ducts. Unlike a typical air conditioning unit, a mini split can dry the air with a very small amount of cold air.