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BUYER GUIDE: DIY (Do It Yourself) Air Conditioning

BUYER GUIDE: DIY (Do It Yourself) Air Conditioning

Last edited: 7th September 2023

DIY air conditioning are Monobloc (all parts contained inside one casing) systems with the indoor and outdoor units of a split system, built into one casing and mounted in the room in which the system will be used.

The units come in a variety of sizes, from as small as 1.7kW and go up to (approximately) a huge 3.6kW! There are now numerous manufacturers of these products on the market, offering a variety of different features to entice buyers towards their products.

As these great units are a monobloc design, there is no need to find space for a separate unit to go outside the property. They rely on 2 larger and 1 smaller holes to be drilled through the wall, which then have a tubular insert attached and are covered with a grille to operate, therefore lowering the cosmetic impact on the exterior of the property greatly.

One of these larger holes is used to bring cool air into the unit (NOT into the room), while the other is used to extract hot air generated by the units operation, using the same basic refrigeration cycle as a conventional split system. The smaller hole is used as a condensate drain, to expel water from the unit.


As these units do NOT rely on an indoor and outdoor unit to be connected via refrigeration pipes, there is no need to employ the services of an F-GAS registered engineer to carry out the installation. All you need is to purchase a core drill cutter in the correct size and you can do it yourself (hence why we call the units in the category DIY Units).

It’s best to do your research on each product you consider though, as the hole sizes vary per manufacturer and can vary from approximately 150mm up to (and likely over) 202mm, so you will want to ensure you purchase the correct tools for the job.

Should you choose to do the job yourself, the good thing is most manufacturers supply the units in a sort of kit form, where all required hardware (not including tools) is included in the box. This normally includes the cooling unit itself, 2x grilles, 2x flat plastic sheets (rolled up to make the vent tubes), a short length of pipe (for condensate drain) and a bracket (for attaching to the wall).

You should be aware that these units often weigh in excess of 35kg, so you should ensure your desired mounting location is strong enough to hold the weight of the unit.

There are companies out there that specialize in the installation of these units, as although they don’t require an F-GAS registration to install them, they do still require a good level of skill to ensure they are fitted correctly. If you would like to know more or be put in touch with one of these specialist companies, give us a call on 0800 458 0101


As with all Air Conditioning systems/units it is essential that you get the correctly sized product for the area you will be operating it in. Each manufacturer will list the rated output of the unit in kW Kilowatt) or Btu (British Thermal Unit) and this will let you know if the unit is large enough to cover the size of the area you wish to locate it.

Failing to get the correctly sized product for the room you wish to use it in, will result in poor performance, shorter system life span and greater running costs (you can see our size chart for reference on the Buyers Guide home page).


Most units are available in a horizontal orientation, with a few manufacturers even offering vertically orientated units, giving a slimmer but longer profile on the wall.
The horizontal units are usually low wall mounted, similar to a heating systems radiator (the majority choice for most users) or high wall mounted (which may result in purchasing a non-included bottom cover, to cover the units internals).

Noise Levels

Because of the design of this style of unit, they are always going to produce a higher decibel level when compared to a split-type system of the same power output. This is because they have the compressor (the motor of the unit) neatly compacted inside the casing, which is then installed into the desired room’s location, as opposed to a split-type system, where the compressor is in the outdoor unit.

However, even with the noisiest part of the system being inside the room, these are remarkably quiet products with some manufacturers managing to achieve an astoundingly low 27db!


With most manufacturers nowadays utilizing inverter driven compressors, air conditioning products in general have become extremely efficient to use for both cooling and heating. The majority of units on the market are achieving a COP (Co-efficient Of Performance) of 3.1 upwards. Make sure you look at the technical data from each manufacturer to compare products efficiency ratings.


As mentioned above, inverter technology became a game changer in the air conditioning product world. Not only has it given the ability to achieve far greater efficiencies in cooling mode, it has also enable the use of air conditioning systems to double as HEAT PUMPS.

Now, not all units that fall into the DIY or monobloc category include this technology, but the vast majority does and it is well worth paying the extra for a product that does. Purchasing a product that gives the ability to cool in the warmer months and then heat in the cooler months, will enable year round use, making these devices perfect for climate control in all seasons.

Controls & Compatibility

Ensuring you have easy control of your device is essential to get the maximum ease of use. Most devices come with an IR (Infrared) remote control and also either a touch screen or physical button input panel, to operate and adjust settings according to user requirements.

With the advancements in modern technology, more and more products on the market are becoming Wi-Fi and smart enabled, allowing users to operate devices from numerous devices. While not every monobloc unit on the market may include this technology, there are plenty that do, so if this feature is important to you, ensure the product you are considering includes these features.

You may be asking “Why would I want Wi-Fi control?” Well, having this feature on the device means that you can control the device remotely. If you have a unit installed in your home and it’s a hot day, you can switch the unit on before you arrive home, to ensure you walk into a nice comfortable and cool environment. Having Wi-Fi control of the system also gives the ability to users such as hotel chains the ability to turn off the device if a guest has checked out, but left the unit operating.

Warranty & Servicing

The biggest negatives to the products that fall into this category, is that most manufacturers only supply a 12 month warranty period and no real servicing schedule.

In order to achieve the most efficient use of the product, it is best to keep the unit clean and ensure there are no obstructions in the inlet or extract vent ports.
All devices will have a mesh filter on the unit, which is a serviceable item by the user and is designed to filter out larger dust particles. This stops the unit from getting clogged up internally and aims to make the air being recycled within the room cleaner and fresher.