What is a mini-split heat pump and do I need one in the UK?

A mini-split heat pump simply means a ductless system that provides both heating and cooling to homes. It consists of an outdoor unit and an indoor unit, where the temperature of certain rooms is controlled. This is its main difference to the traditional ducted heat pump – which would be used for the entire house.

How does it work?

It works by using a closed loop refrigerant cycle (the heat is transferred, as opposed to being generated.) For example, in the winter, refrigerant will absorb heat from the air outside and release it indoors. In the summer, the indoor unit absorbs the heat so this can be released via the unit outdoors.

Types of mini-split heat pumps

There are various types available, with the most popular being the following:

• Wall-mounted units: These are placed high up on a wall and are renowned for being an affordable option for living spaces like the bedroom or even for a home office.
• Ceiling cassettes: For those with limited wall space or large rooms, this is a good option which usually provides 360-degree air flow – with the unit being installed flush mounted into the ceiling.
• Floor mounted: If you don’t have much wall height, consider the floor mounted version as these are placed low down on the wall or floor. Attics or basements are often used with this type of Mini Split installation.
• Ducted mini-split: Whilst most mini-split heat pump system are ductless, this one is not. In this case, short-run, concealed ductwork is utilised to deliver air to single or multiple rooms. This way the unit is kept out of sight – often in attics or ceilings.
• Single zone systems – where one outdoor unit is connected to one indoor unit.
• Multi-zone systems – one single outdoor unit connected to multiple indoor units. (Both single-zone and multiple-zone are ductless set ups).

Mini-split benefits

The latter of these systems is going to be ideal for a whole house cooling/heating, with the former single-zone being more suited for small apartments, basements, or any one room needing control of temperature.

Very good levels of Energy-efficiency can be expected with mini-split systems. They will most often score highly on the SEER ratings (seasonal energy efficiency ratio) so you can save money on your utility bills here. This is because Mini Split Systems will typically have no ducts, so energy isn’t lost via the ductwork.

How much does a mini-split heat pump cost?

In the UK, if you’re considering ductless air conditioners then you can expect to be paying between £1,500 to £5,000 as a broad cost.

More specifically, a single-zone installation would be between £1,500 to £3,000. Meanwhile, a multi-zone would cost between £3,000 to £5,000. A living room and two bedrooms for example, puts you in the multi-zone category.

Of course, the more rooms required, the more you can expect to pay so if you require four or more indoor units then you can expect to pay over the £5,000 mark.

The type of indoor unit will also affect price with wall mounted option typically being the cheapest. On the opposite side of this, a ceiling cassette would be more expensive due to installation being more intensive in labour costs and more complex components.

Is a mini-split pump right for my home?

It can be if your home does not have existing ductwork, which are typically older houses. However, the aesthetic should also be considered as having visible units indoors will not appeal to everyone so it’s important to decide if you feel the comfort of having this very efficient system would outweigh this.

Remember, with the mini-split system you are getting both heating and cooling in a single, ductless operation. You will be getting targeted zone control so the temperature can be controlled in individual rooms. This also means that you’ll be only heating or cooling areas that are being occupied, so you’re being very energy efficient.

Closing Thoughts

Ultimately, you should assess what your house already has first. If you already have duct work, then you may want to install a central ducted heat pump instead. However, if you’re after that zoned climate control in each room and high energy efficiency, then a mini-split installation could be perfect for your household.