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

It’s no secret that mini splits have been gaining traction in the HVAC industry. Their eco-friendly technology and low operating costs make them an attractive choice for many homeowners.

These systems are heat pumps, meaning they transfer heat rather than create it. That’s part of the reason they have lower operating costs than forced-air furnaces and boilers. 

But how well do they do in the winter? Can they heat your home when the temperatures drop below zero?

How Does a Ductless Mini-Split Work?

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

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

Mini splits use refrigerant to move heat around, just like a central air conditioner. The refrigerant easily absorbs heat and transfers it where it needs to go.

On cooling mode, they take heat from inside the home and move it outside. On heating mode, the system runs in reverse. It finds heat in the ambient air outside and moves that indoors. 

But what happens when temps drop below freezing?

Do Mini-Splits Work Well in Cold Weather?

When mini splits first hit the market, they were not known for being good in cold weather. But as they gained popularity, manufacturers introduced technology to increase their operating range to include low temperatures

There are mini split models on the market that will work in subzero, and even negative temperatures. 

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

Because mini splits need to find heat in the ambient outside air, a drop in performance can start as soon as temperature drow below 30 degrees Fahrenheit, especially if yours is an economy mini-split.

The biggest benefit of these units is their affordability. They will cost far less than mini split models with lower operating ranges. However, these units are only ideal for those who live in mild climates or only want to use the mini split for supplemental heating. 

They are a popular AC choice for homeowners with boiler and electric baseboard heat. *If you have a mini split just for the purpose of air conditioning, you will be more than happy with one of these cheaper options.

Mid-Level Mini-Splits

Each manufacturer has a slightly different operation range, but the midddle-range units can work in temperatures as low as 20 degrees Fahrenheit.

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

Low-Ambient Mini-Splits

For truly cold climates, a low-ambient mini split is needed. These systems can handle a low end temperature of around -15 degrees Fahrenheit. Some brands can even work in conditions as low as -30. But be aware, these units are not cheap.

Depending on the specifics of your home, you may choose a low-ambient unit, or you may opt for a backup heat source instead (such as electric baseboards). Each home is different, so it would be best to contact a couple of local HVAC companies and ask their opinions.

A technician adjusts the indoor component of a mini-split

One Comment

  1. Ours is a mid level Ductless heating and cooling, and it works until it gets down to the low teens and then it struggles, so we have backup heating.

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