How Often Should a Mini Split Defrost?

You take a chicken breast out to defrost before cooking it for dinner, but you’ve never thought your ductless mini split has to defrost the same way. Do you really have to defrost your mini split and if so, how often?

We’ll answer those questions and more in today’s blog post!

Why Do Ductless Mini Splits Have to Defrost?

Ductless mini split systems are capable of both heating and cooling. This is part of what saves you so much money in owning a mini split, as you don’t have to buy nor maintain separate air conditioning and heating units anymore.

Your mini split system runs on refrigerant either way, but how that refrigerant behaves depends on whether the unit is cooling versus heating your home. For example, when providing cooling, the refrigerant meets warm air and becomes warm as a result. The refrigerant will change state from a liquid to gas during the cooling process, allowing the air to cool down as well. Then the vapor returns to a liquid thanks to the compressor.

So if the ductless mini split system warms up to provide cooling, you can only assume that it becomes cold to provide heating, and you’d be correct. Already then, the interior components of the compressor are going to be colder than usual. Considering that most people use heating when the weather is cold, the compressor is then exposed to the frost, ice, and snow that winter brings, including the very low temperatures.

When parts of your compressor freeze, internally or externally, the unit cannot work. This impedes how much warm air can blow out of the indoor air-handling unit. Before that happens, you should check for a defrost mode on your ductless mini split system.

When defrosting, it’s like the ductless mini split unit is going to cool your home, as that allows the internal components to warm up again. The compressor should thaw and all is well. You can reliably expect your ductless mini split to continue warming your home all winter long for less money than a traditional heater or furnace.

How Often Should a Mini Split Defrost?

If you turn on defrost mode, then the unit will defrost as often as is needed. How many times that is depends on where in the country you live.

If you have very harsh, bitterly cold winters, then your mini split may defrost weekly or thereabouts. In places where the winters are moderate, then maybe your mini split will defrost every few weeks or about every month. Perhaps you barely even have winter. If so, then don’t be surprised if your ductless mini split system never defrosts. It just doesn’t have to.

Your mini split unit can defrost more often if you have gone through an especially bad winter or after a storm. This is normal. However, if the unit tries to defrost even when the weather is somewhat warmer, that’s a problem.