Thinking about getting air con? Good shout. With UK heatwaves now a regular summer guest, a well-placed AC unit can make all the difference.
But here’s the thing - it’s not just about having one, it’s about where you put it. Get the placement wrong, and you risk weak airflow, higher running costs, and a bulky eyesore on your wall.
Whether you’re in a cosy flat, a Victorian terrace, a listed cottage or a modern detached, this guide breaks down exactly where to install your AC - indoors and out - to maximise comfort, efficiency and style.
🔑 Key Takeaways:
Mount indoor units high on external walls for strong airflow and even cooling.
Outdoor condensers work best in shaded, open areas with good ventilation.
Avoid placing units in direct sunlight, tight spaces, or near heat sources.
Good placement means lower bills, quieter running, and a longer lifespan.
What Makes a Location “Best” for an Air Conditioner?
It’s not just about hiding the thing. The “best” spot balances airflow, temperature regulation, noise, accessibility, and cost.
A well-placed unit will:
Cool your space evenly
Use less energy to do the job
Stay quiet (for you and your neighbours)
Be easy to maintain and discreetly installed
Why it matters in the UK:
UK guidance (TM44 inspections and CIBSE standards) highlights that poor air con placement - like restricted airflow or cramped installation - can seriously undermine efficiency.
The Energy Saving Trust also recommends leaving enough clearance around outdoor units for proper airflow.
While UK figures vary, industry best practice suggests suboptimal placement can cut efficiency by up to 20–30%, leading to higher bills and more frequent repairs.
Now, let’s break it down by indoor and outdoor units…
Best Spot for Indoor AC Units
The indoor unit is your main cooling engine, and its position defines how effective it will be.
General Tips ⚠️
For most UK homes, install the indoor unit:
High up, ideally 2 to 2.5 metres above the floor
On an external wall to simplify pipework
Clear of obstructions like curtains or wardrobes
Avoid:
Heat sources like radiators, TVs, or sun-soaked walls
Positioning directly above beds or sofas, which can lead to uncomfortable cold drafts
Room-by-Room Placement
Living Room - mount above or near seating, but not blowing directly at people. Prioritise this room in flats where you can only install one unit.
Bedroom - aim for a wall opposite the bed or above the door. Avoid airflow hitting the bed directly.
Home Office - cool the workspace without blasting cold air directly at your desk.
Kitchen - if absolutely needed, place the unit far from hobs and ovens to avoid misleading the thermostat.
By Property Type 🏠
Flats - external walls may be limited. You may need permission for installation and possibly extended pipework.
Terraced Homes - shared walls and tight rooms make airflow planning crucial. Keep noise away from neighbours.
Detached Homes - these allow more flexibility. Multi-split systems can be used to cool several rooms.
Listed Buildings - you’ll need discretion and often formal approval. Utility rooms or home offices are usually safer options.
“Placement is everything. A badly positioned unit won’t just underperform, it could cost you double to run over summer.” - Patrick Garner, Head of AC Installations at Heatable
Best Spot for Outdoor Condenser Units
The outdoor unit is responsible for expelling heat from your home. Its location affects energy use, performance, and neighbourly peace.
Placement Principles:
Choose a shaded, ventilated area like a north or east-facing wall
Avoid direct sunlight or heat-trapping spaces
Leave at least 30 cm clearance on all sides
Keep it away from bedrooms, windows, and property boundaries
Mounting Options Pros & Cons
Pros | Cons | |
Wall Mounted | Saves ground space, collects less debris, ideal for small gardens | Needs a strong wall and brackets |
Ground Mounted | Easier and cheaper to install, works well in larger gardens | Can collect debris, takes up floor space |
Outdoor Unit Placement by Property Type
Where you can place your outdoor condenser unit depends heavily on the type of property you live in.
Here’s how to get it right for your home:
Flats and Apartments 🏢
Balconies, rooftops, and shared external walls are common locations for outdoor units in flats.
However, you’ll almost always need permission from the building management or landlord before installation.
Wall-mounted brackets are a smart choice for saving space on small balconies and keeping the unit off the ground.
Just be mindful of where the unit vents - avoid placing it near neighbouring balconies or bedroom windows.
Terraced Homes
Space is often tight in terraced houses, so the rear wall tends to be the go-to location.
If you’re mounting the unit close to your property boundary, make sure there’s enough clearance to avoid issues with heat output or noise affecting your neighbours.
Wall-mounting the unit a little higher up can help reduce sound transmission and keep garden space clear.
Detached and Semi-Detached Homes
With more outdoor space to work with, detached and semi-detached properties give you the most flexibility.
You can install the condenser in a shaded garden corner, along a side wall, or even behind outbuildings, provided there’s good airflow.
These properties are also ideal for multi-split systems, which allow you to run multiple indoor units from a single outdoor unit.
Listed Buildings
Listed properties come with stricter rules around external modifications.
You’ll likely need planning permission for any outdoor unit, and the conservation officer may specify how and where it can be placed.
Tucking the condenser into a low-visibility utility area, behind fencing, or using noise-dampening enclosures can help meet the regulations without compromising performance.
Always check with your local authority before proceeding.
Avoid These Common AC Placement Mistakes
Even the best air conditioning system will struggle if it’s installed in the wrong place. These are the most common pitfalls to avoid - and why they matter.
Direct Sunlight
Placing your unit on a sun-soaked wall might seem fine, but it’s one of the worst spots you can choose.
Direct sunlight heats the surface behind the unit, forcing the system to work harder to cool the room.
It can also throw off the thermostat, leading to inaccurate readings, overcooling, and unnecessary energy use.
Cramped or Enclosed Corners
Trying to keep the unit discreet by tucking it into a corner or alcove is a common mistake.
Restricted airflow prevents the system from circulating cool air effectively, which means uneven temperatures, hot spots, and even the risk of the unit overheating. It’s best to give your AC room to breathe.
Too Close to Fans or Vents
Mounting the indoor unit near extractor fans, kitchen vents, or air ducts can confuse the AC’s sensors.
These competing airflows disrupt the temperature readings and force the system to work inefficiently. You’ll end up with poor performance and higher bills.
Over Beds, Cots, or Delicate Furniture
Installing an AC directly above sleeping areas or valuable furniture can cause more harm than comfort.
Cold air blowing directly onto a bed or cot can lead to stiff joints, disrupted sleep, or discomfort, especially for babies or older adults. It can also damage wooden or fabric furniture over time.
Right Outside a Neighbour’s Window
Outdoor condenser units might be fairly quiet, but place one right outside your neighbour’s window and you’re asking for trouble.
In terraced streets or blocks of flats, sound travels. A persistent low hum near a bedroom or living space can lead to noise complaints, strained neighbourly relations, or even forced repositioning.
Why You Need a Pro Installer 🛠️
Installing AC isn’t a DIY job. In the UK, only F-Gas-certified engineers can handle refrigerants legally.
Beyond compliance, professionals know how to get the most out of your system.
They will:
Position units for top performance
Avoid damaging walls, electrics, or pipes
Keep your warranty intact
Handle permissions and complex layouts if needed
They also make sure your setup meets local regulations and looks clean, safe, and discreet.
Final Thoughts
Getting your AC location right is essential for cooling power, energy efficiency, and keeping your home looking tidy.
High, clear walls indoors and shaded, open areas outdoors are the sweet spots.
Match your setup to your property type, avoid the classic mistakes, and always use a certified pro for the install.
Next Steps For Your AC Journey:
When planning to install air conditioning for your home, there are several important factors to consider. Make sure to refer to the following guides to help you make informed decisions:
To dive deeper into these topics, head over to our advice section, check out our YouTube channel for informative videos.
Get a Quote for Air Conditioning Today ❄️
Without boasting you should get your new AC installed with us, here's why:
Thousands of Happy Customers: We boast an average score of 4.9 on Trustpilot, outperforming the market leader.
Which? Trusted Trader: Heatable is proudly recognised as a Which? Trusted Trader.
MCS Accredited: Our accreditation by the Microgeneration Certification Scheme (MCS) ensures high-quality standards.
Flexible Payment Options: Choose from multiple payment methods, including finance options.
Fixed Price Guarantee: Enjoy transparency with no hidden costs.
Save Your Quote: You can save your quote and decide later.
