A homeowner on a couch adjusts the setting of his mini-split using a remote control

Brrr! An unseasonable chill is in the air. Now is the perfect time to test out your new ductless mini-split system, which you had relied on all summer long to keep you cool. But, to save you the trouble, we’ve got the dirt on how well these systems work in cold weather.

This article will first discuss how mini-splits function, what temperatures they can handle in the winter, and how to keep your system working efficiently when it gets frigid.

Let’s begin!

How Does a Ductless Mini-Split Work?

Usually, if you want to warm your home, you turn on your heater or furnace, right? When you want a cooler home, you power on your air conditioner.

Besides the undeniable energy efficiency, one of the most significant benefits of a ductless mini-split system is that the unit can both heat and cool.

So how do these systems provide heating? Allow us to explain. 

Your mini-split will include a heat pump. This isn’t like your ordinary heat pump, as it’s ductless as well (it is part of a ductless system, after all).

You already know that a ductless mini-split system comes with an outdoor condenser or compressor and at least one indoor air-handling unit but usually several. Wiring connects the two.

An illustrated diagram of how a ductless mini-split system functions
Courtesy of Fine Home Building

So here’s how a mini-split can heat your home. 

Inside the system is a heat exchanger. This component includes a series of coils. The coils will take warm air and transport it where it needs to go.

Before you know it, your home feels nice and toasty! 

You may get some pretty blustery winters where you live. Thus, you’re worried that your mini-split might not be able to withstand the frigid temperatures.

Well, that depends on precisely how cold those temperatures are and the type of unit have.

Do Mini-Splits Work Well in Cold Weather?

Mini-splits work well in cold weather and one variety can handle temperatures down to negative degrees Fahrenheit before any performance loss occurs—a low ambient mini-split. So if you live in a region where you get very cold winters, you might want to consider a low-ambient unit. 

However, given that a ductless mini-split uses outdoor air to provide cooling or heating, if the temperatures are too extreme on either end of the spectrum, the efficiency of the mini-split begins decreasing. 

The outdoor compressor component of a ductless mini-split

Let’s look at how different mini-split types react to freezing temperatures. 

Economy Mini-Splits

The drop in performance can start as soon as temperatures reach 30 degrees, especially if yours is an economy mini-split. If the temperatures dwindled down to 20 degrees, the system would likely turn itself off.

Although they’re affordable, an economy unit only suits customers who live in a region where the weather is warmer to temperate throughout most of the year. If 60 degrees is considered a chilly day for you, you can use one of these systems without worrying about a decrease in performance. 

Mid-Level Mini-Splits

If yours is a mid-level mini-split, the machine can continue working in temperatures as cold as 20 degrees. However, the system could power down if the temps reach the teens on a freezing winter night.

If it continued working, its efficiency would be reduced. 

The difference between an economy and mid-level unit is that the latter includes a base pan heater. 

This heater is designed for water to drain after the machine defrosts in frigid ambient temperatures. Further, a base pan heater will keep the system from developing ice on interior or exterior components.

A diagram showing where the base pan heater component of a mini-split is
Courtesy of Samsung

That’s how a mid-level mini-split can withstand temps down to 20 degrees.

Homeowners in colder regions can use a mid-level system to both cool and heat their homes, but the outdoor temperatures should only get moderately cold in the winter. 

If wintertime for you means temps in the teens or even the single digits, then a mid-level model is not the best solution. 

Low-Ambient Mini-Splits

What if a typical winter for you is temps down to near freezing or below freezing? You can’t use an economy mini-split without straining the system, nor is a mid-level model a viable solution. 

You have one more option, and it’s known as a low-ambient ductless mini-split.

A low-ambient system can keep chugging right along and working at 100% efficiency even if temperatures dip under 20 degrees. This system type can handle temps below zero degrees.

Should your city or town get hit with a cold blast, and you’re stuck with negative temperatures for a couple of days, even then a low-ambient unit would still work. However, in negative temperatures, the machine’s efficiency would be called into question.

You might not care much if your mini-split will be as efficient as usual as long as it will keep you warm in negative temperatures. But keep in mind that a lack of efficiency will cost you more on your monthly utility bills, even if that’s only a temporary blip. 

Further, working at less than 100% operational efficiency could cause your mini-split to strain.

You should call your mini-split technician when the temperatures get a little warmer so they can determine whether your unit is in good shape after that winter freeze. 

A technician adjusts the indoor component of a mini-split

Another point we must make is that even though a low-ambient mini-split can withstand temperatures far lower than an economical or mid-level model, these machines are not impervious to damage.

They, just as any mini-split, have a cut-off temperature at which it will automatically turn itself off if the temperatures reach or drop below that limit. The limit might be about -30 degrees, and you may never get there. If you do, though, you should understand why your mini-split would stop working in that scenario. 

Tips to Keep Your Mini-Split Operational All Winter

When the days are short, and the weather is cold, your system needs more maintenance than usual. By regularly committing to the following tasks, you can ensure it is in working order throughout the winter when you’ll need heating the most!

Use the Defroster

A ductless mini-split includes a defrost setting. You should be able to toggle this on or off on the outdoor compressor or condenser. 

When the defrost setting is turned off by default, the plummeting winter temperatures combined with condenser coil moisture allow any remaining liquid in the mini split to freeze. 

As conditions get colder, the condenser coils themselves can freeze. The result is a home that feels a lot colder because your system simply cannot warm up your zones to the recommended level.

Leave it on throughout the winter once the defroster setting is turned on.

Keep the Condenser Free of Snow

When it snows, it’s good to go outside once the bulk of the storm is over and brush off your outdoor condenser. Unfortunately, snow on the exterior of this component makes it have to work that much harder to create and maintain warm ambient temperatures in your home.

Raise the Condenser

If you live in cold enough conditions where you have to consider a low-ambient system, you probably get lots of snow and ice. As the snow accumulates first in inches and then in feet, the condenser gets covered in snow from its base upward. 

You can always shovel the snow, but you don’t want your shovel to accidentally collide with the condenser, as that can be injurious.

You might want to get the condenser mounted higher when the technicians initially install it. The recommended mounting height is at least two feet, but ask your technician what’s suitable for your region.

Since the condenser will be elevated, it is unlikely to be affected even if the snow falls and accumulates. 

Conclusion

A ductless mini-split heat pump can reverse operations and provide more than adequate heating in your home all winter long. However, depending on what a typical winter day looks like for you, some mini-split performance losses may occur.

Economical mini-splits can work until the temps drop to 30 degrees, mid-level systems can handle temps down to 20 degrees, and a low-ambient unit can withstand single digits into negative temperatures with dwindling performance as it gets colder.

We hope the information in this guide helps you choose a mini-split that’s right for you! 

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