A ductless mini-split in the corner of a room below the ceiling

Mini-split systems are small, flexible heat pumps that can be used for heating and cooling single rooms or zones of a building.

They are a popular choice for retrofitting existing houses because they are easier to install than ducted systems and often work out cheaper.

Ductless mini-splits provide either heating or cooling to your home and are easy to install compared with other types of space heating. However, as with all HVAC systems, the refrigerant lines must be connected or ‘charged.’

One common question among homeowners considering a ductless mini-split is if these systems come with refrigerant lines precharged.

This article will cover the benefits of precharging, the types of refrigerant used, and why this matters. By the time you’re done reading, you’ll know the basics of refrigerant charging and the right choice for you.

Do Ductless Mini-Splits Come Precharged?

As a general rule, ductless mini-splits come ‘precharged’ with refrigerant. The manufacturer typically carries out precharging of ductless mini-split systems in the factory as part of the production process.

It’s more than just a convenience for your HVAC technician, who will need to spend less time setting up your unit. It can provide benefits in terms of quality control, minimize the risk to the environment, and lower the cost of installation.

Benefits of Precharged Mini-Splits

Some of the benefits of precharging a mini-split system include:

  • Eliminating the need to purge and charge the line set during installation and commissioning
  • Handling the line sets is simplified, reducing the likelihood of refrigerant escaping and minimizing environmental harm
  • Improved safety when installing the line sets
  • No need for specialized tools, which makes certain models compatible with a DIY approach.

However, despite all the advantages, there are a few downsides you should be aware of when using precharged line sets.

Drawbacks of Precharged Mini-Splits

One minor issue is that you cannot cut the precharged line to length without losing the benefits of precharging. This consideration means that the leftover ‘spare’ line must be coiled up next to the external unit, which some homeowners may think looks untidy.

This is not a big issue and can be mitigated by good management. For example, neatly coiling the lines or finding a way to conceal them in an aesthetically pleasing way – perhaps using a screen or cover – can overcome this.

Refrigerants Used In Mini-Split Heat Pumps

You might be wondering what refrigerants are used for mini-splits and why it matters. So, let’s look at the common types and how they differ.

But first, what is a refrigerant, and what does it do?

A technician adjucts the pressure on a refrigerant tank being used in a mini-split system

What is a Refrigerant?

A refrigerant is a fluid – usually a gas at room temperature and pressure – that has suitable thermodynamic properties for use in the refrigeration cycle. Making use of this cycle, a mini-split collects heat from the cooling side of the system and moves it to the warming side using electrical energy.

The heat is collected and transported using the refrigerant, so the characteristics of the chosen one are fundamental to the effective and efficient operation of a mini-split.

For more information about the refrigeration cycle, read our article about how heat pump water heaters work.

Environmental Impact of Refrigerants in Heat Pump HVACs

The impact of refrigerants on the environment has been significant. As a result, it is the subject of many government mandates and international agreements, such as the Montreal Protocol, which covers the phase-out of hydrochlorofluorocarbons (HCFCs) by 2030, amongst other measures.

Minimizing refrigerant leaks by using precharged lines is a good way to keep the installation of your mini-split heat pump environmentally friendly.

The two most significant environmental concerns surrounding certain refrigerants are depletion of the ozone layer and global warming.

Mini-Split Heat Pumps’ Ozone Depletion Potential (ODP)

The hole in the ozone layer was big news in the late 80s when the British Antarctic Survey team noticed abnormally-low ozone levels above the South Pole.

The ozone layer serves to block the worst of the sun’s ultraviolet radiation and prevent it from reaching the earth’s surface. Without it, thousands of Australians were facing the risk of a higher prevalence of skin cancer.

A satellite photo of the earth's ozone layer

If you were in Australia at the time, you might remember the “slip, slop, slap” slogan encouraging everyone to slip on sunglasses, slop on sunscreen, and slap on a hat.

Refrigerants leaking from HVAC equipment, including mini-split heat pumps, were found to be one of the causes of the depletion of the ozone layer, and policymakers quickly introduced measures to stop these substances from entering the atmosphere.

Thanks to the swift action and signing of the Montreal Protocol by the scientific and international community, the hole in the ozone layer is expected to return to pre-1980 levels by this century’s end.

Mini-Splits’ Global Warming Potential (GWP) 

Governments worldwide are constantly working towards reducing the amount of carbon dioxide and other greenhouse gases that humans release into the atmosphere.

Greenhouse gases, including some refrigerants used in mini-split heat pumps, absorb infrared radiation from the sun and keep it in the atmosphere, like a blanket over the earth.

We are all familiar with the consequences of global warming, including higher temperatures and more extreme weather events, and rising sea levels. These changes are affecting many species already and are impacting the lives of millions of people worldwide.

It is crucial to ensure that refrigerants used in mini-split heat pumps have lower global warming potential. Using precharged refrigerant lines also helps to minimize the escape of refrigerant during installation.

Refrigerants With the Least Environmental Impact

As a responsible citizen, you are undoubtedly wondering which refrigerants will have the most negligible environmental impact, so you can choose them for your mini-split system.

This is a complex subject, with many different refrigerants, but let’s look at a few examples:

  • CFC-12 – very high GWP of 10,900 is ozone-depleting.
  • HFC-152a – lower GWP of 124 is not ozone-depleting.
  • HFO-1234yf – low GWP of 4 is non-ozone depleting.

Global warming and ozone-depleting potential figures are available in our round-up of some of the most common refrigerants here, should you wish to learn more about their characteristics.

The key takeaway is that refrigerants vary widely in their environmental impact, and it is vital to choose a system that uses the least damaging of these whenever possible.

How Much Does Recharging a Mini-Split Cost?

Typical costs for recharging a mini-split range between $100 and $300, depending on where you live and the type and complexity of the system you run.

A technician recharging a refrigerant tank used in a mini-split

Always ensure you use a qualified technician for recharging your mini-split system. This precaution will help to ensure the job is done best, resulting in your system operating at maximum efficiency and keeping any potential impact on the environment to a minimum.

Summary 

Ductless mini-splits typically come precharged with refrigerant, which reduces the risk of refrigerant escaping into the atmosphere.

It is essential to minimize refrigerant emissions due to the damage they can do to the ozone layer and their contribution to global warming.

Precharged lines when installing ductless mini-splits simplify the task, making it quicker, cheaper, and less risky to the environment.

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