The best split air conditioners, compared.
Top pick: Generic 12,000 BTU wall split Best value: Generic 12,000 BTU wall split AC12000 – Lowest wall-split price here, at about £500, with SEER 6.2, R32 and heat-pump heating if a fitter agrees first. Updated October 2026.
A split air conditioner puts the cold coil in the room and sends heat outside, which is why many reviewers find it more effective than a single-hose portable. The hard part in the UK is the install path, not the BTU in the title. Opening the refrigerant circuit needs a personal F-gas certificate, Category 1 or Category 2 within the GOV.UK charge limits, and company certification if the engineer works for you. “Pre-gassed” does not remove that rule. We look for a SEER that matches the energy class, a noise figure you can interpret, and an installer who will fit that exact unit. Fixed indoor units are also covered in our [wall air conditioners](/hub/cooling/wall-air-conditioner) comparison. A wall split has an indoor unit, an outdoor condenser and pipes through the wall. A portable split keeps a sealed connection and a short hose, so ordinary temporary use may not need a drilled hole. This set, checked on amazon.co.uk, has nine splits.
A split air conditioner puts the cold coil in the room and sends heat outside, which is why many reviewers find it more effective than a single-hose portable.
32 products checked · 64 hrs invested · +18,600 readers
Swipe for more
1-2 of 9
Personal buying guide
Question 1 of 2
Can an F-gas fitter install a wall unit for you?
This 12,000 BTU wall split is listed for rooms up to 25 m², with cooling, heat-pump heating and dehumidification in one fixed system. Its SEER 6.2 and A++ field are mutually plausible, although a separate A+++ bullet makes the efficiency claim less tidy. The stated 23 dB figure is not labelled as indoor sound, outdoor sound or a particular operating mode, so it cannot support a bedroom-noise promise. All three ratings are five-star, but that is far too small a sample to establish reliability. One buyer reported missing parts, though the seller sent them before the engineer arrived. It is a reasonably specified option on paper, provided an installer checks both the kit and the installation route before purchase.
Pros
Cons
Best for: An owner-occupier cooling one medium-sized room who has already found a fitter willing to check and install the unit
Less suitable: Anyone needing independently verified noise data, strong review evidence or installation included
Specifications
Common questions
What output and room size are printed?
Cooling power is 12,000 BTU. The title and a bullet say 3.5 kW for rooms up to 25 m². The wattage field is 1,580 W. The capacity field says 1 ton. The floor-area field is 25 m².
Who does the listing say should fit it?
The included line names an outdoor unit, an indoor unit, a drain hose and pre-gassed. There is no F-gas sentence and no statement that fitting is included. One review says parts were missing and the seller sent them because an engineer was coming.
Which energy figures are on the listing?
The efficiency field is A++ and SEER is 6.2. Annual energy is 293 kWh. A bullet says A+++ cooling. The noise field is 23 dB with no indoor or outdoor label.
This 9,000 BTU wall split is pitched at bedrooms up to 22 m² and gives a specific 22 dB claim for the indoor unit. Cooling, heating, dehumidification, sleep mode and display-off cover the functions most useful in a single room. The capacity field of 2.6 tons is inconsistent with the 9,000 BTU title, so it should be ignored until an installer confirms the product label. One captured review says the unit was fitted in an afternoon but arrived without outdoor feet, which the buyer made themselves. A five-star average from two ratings is encouraging but not enough to establish quietness or reliability. It is a plausible small-room wall unit, though the undocumented refrigerant and lack of warranty details call for checks before purchase.
Pros
Cons
Best for: One small room where an installer can verify the model and a low indoor setting matters
Less suitable: Buyers who need proven night-time noise, complete mounting hardware or strong after-sales evidence
Specifications
Common questions
What room size and output does the listing print?
Cooling power is 9,000 BTU. The bullet says it is for spaces up to 22 m², and the room type is Bedroom. The capacity field says 2.6 tons. There is no wattage field and no SEER number. The title says A++.
What is in the box, and what did the review say about fitting?
Included components are a remote control and an installation kit. The one review text says the buyer fitted it in an afternoon and that feet were not included, so they made their own. There is no F-gas sentence.
How is the noise described?
The noise field says 22 decibels. The bullet says that figure is for the indoor unit, with sleep mode and a display-off feature. The listing is 5.0 from 2 reviews, and the file has one review text.
The Midea PortaSplit delivers a stated 12,000 BTU or 3.5 kW without requiring a drilled refrigerant connection for normal temporary setup. Its separate outdoor section avoids keeping the compressor beside you, and reviewers repeatedly say it cools more effectively than a single-hose portable. The 39 dB(A) claim applies specifically to silent mode at 1 metre; one reviewer says full cooling is louder. At 45.5 kg with an approximately 2 m fixed connection, it is portable in installation terms rather than easy to carry from room to room. App and remote control are useful, although one review reports a paid SmartHome tier after a trial. It costs considerably more than the generic alternatives, but its 23 ratings provide the strongest user evidence in this comparison.
Pros
Cons
Best for: A renter or owner who cannot install a wall split but has a suitable outdoor position within the fixed connection length
Less suitable: Frequent room-to-room moving, tight budgets or rooms without a safe nearby outdoor position
Specifications
Common questions
What capacity, noise and weight are printed?
Cooling power is 12,000 BTU. A bullet says 3.5 kW. SEER is 6.1 and the efficiency field is A++. Noise is 39 dB, and the bullet limits 39 dB(A) to silent mode at 1 m. Item weight is 45.5 kg. There is no floor-area field.
Does the listing say an engineer must fit it?
There is no F-gas sentence. The outdoor-unit-required field says No. Included components list a user manual. Review texts describe placing an outdoor section without drilling, on a pipe of about 2 m.
What do the reviews repeat?
The listing is 4.3 from 23 reviews. The file has 17 UK texts. Several say it cools better than a single-hose unit. Repeated limits are weight, a short fixed pipe, silent-mode noise, and a paid SmartHome tier.
The AC12000 combines a stated 12,000 BTU or 3.5 kW output with a 25 m² room figure and 600 m³/h airflow. At £500 it is the least expensive wall split in the set while still listing inverter operation, SEER 6.2, R32, Wi-Fi and heat-pump heating. The listing also correctly flags that a qualified fitter must handle the pre-gassed system under F-gas rules. Its 54 dB field is not labelled indoor or outdoor, and the annual-energy cell is clearly malformed. The only review is about failing to find a firm willing to install a customer-supplied unit, not about cooling performance. It is the best-value proposition on specifications and price, but only if a fitter agrees to the model before you order it.
Pros
Cons
Best for: A budget-conscious owner cooling one medium room who has written agreement from an F-gas installer before ordering
Less suitable: Anyone buying before arranging installation or requiring well-established reliability and noise evidence
Specifications
Common questions
What capacity and room size are printed?
Cooling power is 12,000 BTU. A bullet says 3.5 kW and 600 m³/h. The wattage field is 3.5 kW. The floor-area field is 25 m². Noise is 54 dB. The capacity field is printed as 1 ton.
Does the listing say who should install it?
A bullet says the indoor and outdoor units are pre-gassed and sealed so a qualified fitter can install them, and that the gas is governed by F-gas regulations. Included components list a remote, app control, a manual and pre-gassed. No pipe lengths are itemised.
What does the only review say?
The one UK review, 4.0 from 1 rating, says the buyer could not find anyone willing to fit the unit. It says fitters have to be on the F-gas register and only wanted to fit their own equipment. The review does not describe cooling or noise.
This 18,000 BTU wall split targets a larger room than the 9,000 and 12,000 BTU models, with heating, dehumidification and a stated airflow of up to 850 m³/h. Its SEER 6.1 and A++ class form a plausible pair, and the listing explicitly says an F-gas engineer should install the pre-gassed system. The title says 5.1 kW while the wattage field says 5.3 kW, so sizing should be confirmed from the product label rather than the marketplace fields. One of only three reviewers could not connect Wi-Fi and found no instructions for it. Another described fitting as simple, but that is not a substitute for certified refrigerant work. The output-to-price proposition is attractive on paper, yet the sparse and mixed feedback keeps it below better-evidenced choices.
Pros
Cons
Best for: A larger living space where a certified installer has confirmed the required capacity and agreed to fit this model
Less suitable: Buyers relying on proven app control, detailed documentation or substantial reliability evidence
Specifications
Common questions
What output figures are printed?
Cooling power is 18,000 BTU. The title says 5.1 kW. The wattage field says 5.3 kW. The capacity field says 1.5 tons. A bullet says up to 850 m³/h. SEER is 6.1 and the efficiency field is A++. Noise is 27 dB. There is no floor-area field.
Does the listing include installation?
A bullet says the indoor and outdoor units are pre-gassed for a qualified F-gas certified engineer. Included components are the indoor unit, the outdoor unit and a user manual. Fitting is not listed as included.
What do the three reviews say about Wi-Fi?
The listing is 3.5 from 3 reviews. One reviewer says cooling and heating work, but Wi-Fi is not in the manual and they could not connect it. Another says the unit was simple to install.
This compact portable split is listed at 5,000 BTU with a 2 m tube and no permanent drilling, making it easier to consider for a rented room or campervan. The bullets give 40 dB indoors and 55 dB outdoors, which are more usable than the obviously incorrect 1 dB marketplace field. Cooling-only operation, 130 m³/h airflow and a short connection make it a small-space product rather than an alternative to a high-output wall split. Three captured reviews describe successful use in a small room, rented flat and campervan, but the total rating is only 3.0 from four. The listing also conflicts on weight, saying both 13 kg and 15 kg, and gives no warranty. Its low entry price is appealing, but the weak documentation and evidence make it a cautious choice.
Pros
Cons
Best for: Occasional cooling in a small rented room, tent or campervan where the outdoor section can sit within 2 m
Less suitable: Larger rooms, heating use or buyers who need a clear warranty and dependable specifications
Specifications
Common questions
Which noise figure should you read?
The noise field says 1 decibel. The bullets say the indoor unit is 40 dB and the outdoor unit is 55 dB. Cooling power is 5,000 BTU and the title airflow is 130 m³/h. Heating is not claimed.
What does the listing say about fitting?
The title includes a 2 m tube. Bullets say there is no window kit, no wall drilling and no permanent installation. The outdoor-unit field still says Yes. Included components list filters. Warranty is None.
What do the reviews describe?
The listing is 3.0 from 4 reviews. Three UK texts are in the file. They describe a small space, a rented flat with no drilling, and a campervan. None of those three names a fault. The weight field is 15 kg and a bullet says 13 kg.
The 24,000 BTU headline promises 7.0 kW of cooling and heating for an open-plan or larger-room application. It also lists R32, remote control, four fan speeds and a 27 dB(A) figure, but does not identify the measurement position or mode clearly enough for comparison. The energy information stops at class claims, with no SEER or SCOP number to check. More seriously, the product has a 1.0 rating from a single customer and no review text explaining the failure. The listing omits the model number, included installation parts, warranty and installer requirement. High nominal output does not compensate for that lack of traceable product and support information.
Pros
Cons
Best for: Only a buyer whose installer can verify the exact model, specification, parts and support before purchase
Less suitable: Most domestic buyers, especially anyone choosing by the 24,000 BTU headline alone
Specifications
Common questions
What output and noise are printed?
Cooling power is 24,000 BTU. A bullet says 24,000 BTU/h (7.0 kW) for cooling and heating. Noise is 27 dB, and the title says 27 dB(A), with silent mode and sleep mode. The room type is Living Room. There is no floor-area field.
What energy class and refrigerant are stated?
The title says A++ and includes the words Energy Class A++. A bullet says A++ SEER for cooling and A+++ SCOP in warmer climates. No SEER or SCOP number is printed. R32 is in the title and a bullet. There is no inverter field.
Is there a review text?
The listing line is 1.0 out of 5 from 1 review. The file has no review body, no model number, and no included-components line.
The WC18 is listed as a 24,000 BTU, 6.8 kW wall split for up to 35 m², with 980 m³/h airflow and heat-pump heating. Its package is unusually explicit, naming 3 m copper and electrical runs, a wall bracket and a 2 m drain, as well as a qualified fitter. The printed SEER 16.0 does not fit the accompanying A++ class and should not be used to estimate efficiency. A 48 dB noise field is likewise not identified as indoor or outdoor sound. There are no customer ratings to test the listing's performance, reliability or support claims. The complete-looking kit may simplify a quotation, but an installer still needs to verify every component and the true energy label.
Pros
Cons
Best for: A larger room where a qualified installer has checked the capacity, kit lengths and genuine energy label
Less suitable: Anyone who wants review-backed reliability or intends to compare products by the printed SEER figure
Specifications
Common questions
What room size and output are printed?
Cooling power is 24,000 BTU. The title and the wattage field both say 6.8 kW. The floor-area field is 35 m². A bullet says 980 m³/h. The capacity field says 24,000 quarts. Noise is 48 dB.
What is in the pipe kit, and who should fit it?
A bullet lists 3 m of copper pipe, 3 m of electrical wires, a stainless outdoor wall bracket, a 2 m drain pipe and a remote. Another bullet says the units are pre-gassed and sealed for a qualified fitter and names F-gas regulations.
How is the energy line printed?
The efficiency field is A++. The SEER field is 16.0. The annual energy field says 390 kilowatts. There is no customer-reviews line in the file. Do not use that SEER figure as a measured result.
The ZJUNLI is a 5,000 BTU portable split whose 1.5 m connection lets the heat-exhaust section sit outside without drilling. It is listed for rooms up to 20 m², with 130 m³/h airflow, a 40 dB indoor figure, sleep mode and a 12-hour timer. At a stated 13 kg it is much lighter than the Midea PortaSplit, although the shorter tube gives you less freedom to place it. The package includes both sections, a dual hose, remote and washable filter. There is no customer rating, energy figure, refrigerant detail or warranty information to support the seller's claims. This is a flexible-looking cooling-only option, but the near-empty evidence means the room-size and noise promises should be treated as unverified.
Pros
Cons
Best for: A small rented room, tent or van where a light cooling-only split can reach a nearby outdoor position
Less suitable: Buyers needing heating, a longer connection or review-backed performance and support
Specifications
Common questions
What is listed in the box?
One indoor unit, one outdoor heat exhaust unit, one dual hose system, one remote, one washable mesh filter and one user manual. The title says a 1.5 m tube, twice.
What room size, noise and modes are stated?
A bullet says up to 20 m², 130 m³/h and an indoor noise of 40 dB, which matches the noise field. The operating mode is Cooling. Heating is not claimed. A 12-hour timer and sleep mode are in the bullets. Weight in a bullet is 13 kg. No spec weight is printed.
Does the file include a star rating?
No customer-reviews line is in the file, so the rating is not stated. A bullet says the unit needs no drilling and can vent through a window, a door gap or a tent flap.
For this comparison we read nine split air conditioner listings on amazon.co.uk, dated 15 October 2026, and checked the fitting and labelling points against public UK sources. Editorial scores use those listing figures and review counts. We did not run a lab test, and we do not treat a five-star average from two ratings as one.
Install path
25%A wall split with a pipe kit is normally not something you connect yourself. We check whether the listing names a qualified fitter, a pre-gassed kit, or a no-drill portable setup.
Room capacity
25%BTU, kilowatts and any printed floor area need to agree. A trade rule of thumb is about 100–150 W per square metre before sun and equipment, and it is only a rule of thumb.
Heat pump
15%Most wall units claim heating. The 5,000 BTU portable splits in this set describe cooling only. Winter use depends on a heat-pump claim you can read on the listing.
Noise and outdoor siting
20%Amazon decibel cells are not the sound-power figures in Regulation 206/2012. We keep a figure only when the listing says whether it is indoor, outdoor or a named mode.
Listing evidence
15%We prefer SEER 6.1 or 6.2 next to A++, and review text over a tiny five-star sample. A printed SEER of 16.0 is not used as a result.
Choose the install path first, then the room, then the numbers you can actually read. A wall split and a portable split solve different constraints, and the shelf price does not include labour.
A split air conditioner puts the cold coil in the room and rejects heat outdoors. Reviewers usually find that more effective than a single-hose portable, because the compressor heat does not stay inside. A wall split has an indoor unit, an outdoor condenser and pipes through the wall. A portable split keeps a sealed connection and a short hose, so ordinary temporary use may not need a drilled hole. This set, checked on amazon.co.uk on 15 October 2026, has nine splits.
Figures such as 22, 27, 39 or 54 dB, and a junk 1 dB field, are not the sound-power measurement capped by Regulation 206/2012. Midea’s 39 dB(A) applies to silent mode at 1 m. A reviewer says full cooling is louder.
The WC18 prints SEER 16.0 next to A++. That pair does not belong together, and it is not a measured saving. Prefer SEER 6.1 or 6.2 written beside A++. Ignore seller lines about 60% lower bills or £13 a season.
One buyer of the AC12000 found no F-gas firm willing to fit a customer-supplied unit. Pre-gassed is not permission to open the circuit yourself. Call a professional for refrigerant pipes, a fixed system, a new circuit in England, or a listed building.
Start with how the unit is connected, because that decides who may install it. A wall split with a copper pipe kit is normally non-hermetically sealed. GOV.UK requires the installer’s details before that equipment is sold to an end user. Personal Category 1, or Category 2 within the stated charge limits (under 3 kg, or under 6 kg if hermetically sealed), is the qualification route, plus company certification when the work is for someone else.
Match output to the room you actually cool. In this set, 12,000 BTU is paired with 3.5 kW on more than one listing, while the 24,000 BTU units print about 6.8 kW or 7.0 kW. Seller areas run from 20 m² to 42 m² across different machines. The PortaSplit has no floor-area field. A trade rule of thumb is about 100–150 W per square metre before you add sun, glazing and equipment. Mark that as a rule of thumb, not a survey.
Three typical situations, each with a recommendation from this comparison.
You need a sealed portable split, outdoor space within the hose length, and permission from the tenancy. The PortaSplit is the option with a stated 12,000 BTU output and the largest review sample, if you can site the outdoor section within about 2 m.
You can book a certified installer for one medium room. The AC12000 is the lowest-priced wall split in the set, at about £500, with SEER 6.2 and heat-pump heating. Order it only after that fitter agrees to fit a customer-supplied unit.
A 9,000 BTU wall split is listed for bedrooms up to 22 m², and the 22 dB figure is described as the indoor unit. Two ratings are not a night-time test. An installer still needs to confirm the model before you buy.
On these amazon.co.uk listings the Midea PortaSplit is the top pick: it has the largest review sample, a stated 12,000 BTU output, and reviewers describe setup without a drilled hole. The Generic AC12000 is the best value wall split at about £500, with SEER 6.2 and heat-pump heating, but only if an F-gas fitter agrees to install a customer-supplied unit first. The 5,000 BTU portable splits are cooling-only options for a small space. A 24,000 BTU title is not a reason to buy when the model, energy label or reviews are thin.
Generic 12,000 BTU wall split AC12000
Lowest wall-split price here, at about £500, with SEER 6.2, R32 and heat-pump heating if a fitter agrees first.
Editorial
Peter F. is the editor for DIY & tools at productscompared.co.uk. Comparisons in this category are checked against amazon.co.uk listings, review evidence and public UK sources.
Guides on what to look for, how to use a product, and common mistakes.
Public UK sources and the manufacturer page below. amazon.co.uk listings checked on 15 October 2026.
Expert source (DIY & tools): Charlie White (Charlie DIYte) (external profile) – public expert commentary used as a research source, not as a contributor to our pages.
This page contains affiliate links to amazon.co.uk. If you buy through them, we may earn a commission at no extra cost to you. Prices and star ratings are taken from those listings. We did not run a lab test.
