Do Mini Splits Heat and Cool?


We need heating during the winter and cooling during the scorching summer. Since mini splits are getting popular nowadays, many people wonder do mini splits heat and cool? So, I decided to write a post.

Mini splits are able to provide both heating and cooling. When cooling, they work just like a normal air conditioner. When heating is needed, they can reverse the flow of refrigerant and change from cooling to heating. Such mini splits are also known as heat pumps.

Some people thought that a mini split does either heat or cool only. They don't realize that a mini split is not just able to cool but also is a good heating solution.

How Mini Splits Heat and Cool?

Mini splits work just like a typical central air conditioner when cooling. They produce cold air at the indoor unit and reject hot air at the outdoor unit.

When it comes to heating, you'll need to switch to heat mode using the mini split controller.

“When shopping for mini splits, make sure to buy heat pumps instead of air conditioners to get the heat mode.”

Mini splits that do both heating and cooling have an extra reverse valve at the outdoor unit. When operating in heat mode, the reverse valve will engage and reverse the refrigerant cycle process to change from cooling to heating.

During heating, the indoor unit becomes the condenser and produces hot air. Meanwhile, the outdoor unit becomes the evaporator and rejects cold air.

Technically speaking, the outdoor unit is absorbing heat from the ambient air and transfer it to the indoor unit before distributing into your house.

If you are interested to know more about the heating mini splits, check out my post Here is Why You Should Use a Heat Pump for Heating where I unpack how much saving you'll get by using mini splits for heating. Also, I covered more on the working principle in the post.

Are Mini Splits Good for Heating?

Most mini splits are able to maintain operation at an ambient temperature as low as 5°F (-15°C). Considering that the winter temperature in most places don't fall below 0°F (18°C), mini splits are pretty good for heating.

If you are living in places that the winter temperature drops beyond 0°F (18°C), do take a closer look on the working temperature of the mini splits. Some mini splits are capable of working down to -22°F (-30°C). Usually, they are labeled as the arctic model or low ambient temperature model.

Vanlife Looks Warm In Theory #Shorts
Vanlife Looks Warm In Theory #Shorts

See more about it in my post Do Mini Splits Work in Cold Weather? I have a list of brand and model that does very well in heating. I also included the best mini splits for extreme cold weather.

Can a Mini Split Heat a Whole House?

Typically, a mini split has a heating capacity from 9,000 BTU up to 24,000 BTU. Though there are mini splits with a heating capacity of more than 24,000 BTU, they are not common and often a lot more expensive.

A 24,000 BTU mini split can only cool 400-600 square feet of space. However, hot air distribution plays an important role here.

Mini splits are ductless and they only distribute hot air through the indoor unit which means that a mini split has only one hot air supply outlet. So, if your house has multiple rooms, you need multiple mini splits to cover the whole house.

Nevertheless, if your house is long rectangular-shaped, you can consider having just one mini split and leave all doors open for the hot air to reach. But, keep in mind that the temperature difference between the far-end room and the room closest to the mini split is significant.

How Many Square Feet Does a Mini Split Cool?

As a general rule, one square foot required 30 btu/hr of cooling capacity. Thus, a 9,000 BTU mini split can cool a room with an area of up to 300 square feet.

However, factors such as windows size and wall insulation can greatly affect how many square feet a mini split can cool. So, be sure to check with your local HVAC contractors and have them assess your house first.

Alternatively, you may check out my posts as below to get more information about sizing mini splits capacity:

Can a Mini Split Cool Multiple Rooms?

How much a mini split can cool is depending on the area it serves. If you have two small rooms, say about 100 square feet each, you can use a 9,000 BTU mini split to cool both rooms.

However, mini splits are ductless. So, you may need to install the mini split in between the wall, 50% for each room, to provide cooling for both rooms.

If you are thinking of cooling 3-4 rooms with a mini split, you can install the mini split in the living room and leave the door of all rooms open if you don't mind.

Alternatively, mini splits do available in ducted type. They are called ceiling concealed type mini splits. They are installed above the ceiling and use ducts and grilles to distribute air.


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Yu Chang Zhen

I enjoy working on air conditioners and ventilation fans because Malaysia is a very hot country.

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