The condenser unit of a mini-split next to a wall outside a home

Mini-split heat pumps are an extremely convenient and efficient way to heat and cool your home. They are more efficient than traditional HVAC systems and can be installed easily in most homes within a day.

They have become an incredibly popular HVAC choice for residential homes due to their energy-efficient technology, but should you leave them running all the time?

Can You (Should You) Leave Your Mini-Split on All The Time?

Mini-splits actually work best when they run non-stop throughout the day. Designed as a “set-and-forget” solution, they automatically adapt to conditions in the home to provide optimal efficiency.

Adjusting the temperature or turning your system off when you go out typically makes mini-splits less efficient.

For more tips on improving your home’s energy efficiency, check out our article on efficiency-improving upgrades with the best ROI.

How Do Mini-Splits Work?

Mini-splits are comprised of two main parts: an outdoor unit, called the condenser, and one or more indoor components, known as air handlers, evaporators, or head units.

The two units are connected by insulated copper refrigerant lines and electrical cables that supply power and allow the units to communicate with each other.

These units work via “heat transfer,” meaning they don’t waste energy creating heat but simply find heat in their environment and move it accordingly. Essentially, refrigerant absorbs heat from one side of the system and moves it to the other.

In cooling mode, it moves heat from inside and expels it outside. Just like a central air conditioning unit.

In heating mode, it works in reverse. It finds heat in the ambient outdoor air (even when it drops to -15°F!) and transfers that heat indoors.

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

These systems are incredibly energy-efficient. The main consumer of electrical energy is the compressor in the outdoor unit.

This is the heart of the system and is responsible for pumping the refrigerant between the indoor heads and the outdoor condenser.

Modern compressors in mini-splits are usually inverter-driven. This is an upgrade from the old type of compressors in traditional air conditioning units.

Inverter-Driven Compressor Technology

Inverter-driven compressors can precisely control the rate at which refrigerant is pumped around the system, allowing a mini-split to generate exactly what it needs to maintain your home’s temperature.

In contrast to traditional systems that adjust the level of heating and cooling simply by turning the compressor on and off, inverter-driven systems adjust the speed according to the heating or cooling load needed.

A homeowners points a remote control at the air handler unit of her mini-split system

Improved Mini-Split Efficiency

In older systems, the first few seconds after the compressor kicks in is incredibly inefficient compared to the steady-state scenario. As the compressor starts up, it must overcome the initial inertia from a standing start.

If you manually turn your mini split on and off constantly, you will experience the same inefficiency as the old style of air conditioners. These units are meant to be set to a comfortable temperature and left alone.

They will adjust themselves accordingly.

The indoor and outdoor units are in constant communication and will use the least amount of energy to maintain temperature, but you have to let the system do its job.

Longevity of a Mini-Split System

The use of inverter-driven compressor technology means there will be considerably less wear and tear on the system.

You might have the opposite effect if you are constantly fiddling with the temperature settings in an attempt to reduce your costs.

Similarly, smart thermostat integrations are not a good choice for these systems. They have their own technology that maintains their energy efficiency and a smart thermostat could disrupt that.

A homeowner adjusts a smart thermostat connected to a mini-split system on the wall of her home


Mini splits are integrated with their own smart technology and benefit from being left alone to do their job.

The best thing you can do to maximize your mini-split’s efficiency is to find a comfortable temperature setting and forget about it. 

That being said, don’t forget to clean the filters on the indoor air handlers! These should be removed and cleaned every 6-8 weeks. You can vacuum them or simply clean them with water and allow to dry.

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