Let’s be honest, UK summers aren’t what they used to be. With heatwaves pushing 40°C in recent years, air conditioning has gone from luxury to lifeline. It’s not just for swanky hotels anymore - more and more British homes are making room for a bit of cool relief.
- What is a Portable Air Conditioner?
- What is a Wall-Mounted Air Conditioner?
- Key Differences Between Portable and Wall-Mounted ACs
- Which is More Energy Efficient in UK Homes?
- Running Costs: Which Costs More Long-Term?
- How Easy Is It to Install a Portable or Wall-Mounted Air Conditioner?
- Are There Low-Carbon Alternatives?
But here’s the big question: Do you go for a quick-fix portable unit, or invest in a wall-mounted system built for the long haul?
At Heatable, we’re all about keeping your home comfortable without draining your wallet - or the planet.
So, whether you’re a renter dodging landlord drama or a homeowner planning your next upgrade, this guide will help you choose the right cooling setup (and dodge a few noisy mistakes along the way).
❄️ Key Takeaways:
Portable air conditioners are cheap, cheerful, and renter-friendly, but can sound like a lawnmower and guzzle energy.
Wall-mounted units (usually split systems) are whisper-quiet, powerful, and energy-efficient, but cost more upfront.
Running costs and installation are worlds apart - short-term savings might sting you long-term.
Portables are ace for quick relief; wall-mounted units are your mate for future-proofing comfort.
What is a Portable Air Conditioner?
Portable air conditioners are the plug-and-play heroes of heatwave season. These wheeled units suck in warm air, cool it using a refrigerant, and vent the heat out through a hose (usually poked out of a window). No installer needed - just plug it in and you’re good to go.
Prices start at around £200, making them a tempting short-term fix. But there’s a trade-off: they’re louder, less efficient, and chew through more energy than fixed systems, so they’re best suited for smaller spaces like bedrooms or home offices.
According to the Energy Saving Trust, portable air conditioners are significantly more expensive to run than standard fans, costing up to 20 times more if left on all day.
So while they can offer quick relief, they’re not the most wallet-friendly option for regular use.
What is a Wall-Mounted Air Conditioner?
Wall-mounted air conditioners, also known as split systems, are the more polished, high-performance cousins of portable units.
They come in two parts: an indoor unit fixed to your wall, and an outdoor unit that whisks away the heat via discreet pipework.
They’re designed for cooling larger spaces like open-plan living areas or upstairs bedrooms, and they do it quietly and efficiently.
Prices typically range from £800 to £2,000, including installation, depending on the size of the system and your setup.
If you’re after a long-term cooling solution with minimal noise and better energy performance, this is the one to watch.
Key Differences Between Portable and Wall-Mounted ACs
Feature | Portable AC | Wall-Mounted AC (Split System) |
Cooling Power | Best for small rooms (up to ~30m²) | Cools larger areas; multi-split options can cover multiple rooms |
Noise Levels | 50–65 dB (comparable to office or pub chatter) | 19–45 dB (similar to a quiet library or soft conversation) |
Installation | No installer needed - just plug in and vent through a window | Requires professional installation and outdoor unit setup |
Portability | On wheels - can be moved room to room | Fixed in place once installed |
Aesthetics | Bulky and takes up floor space | Sleek and mounted high - blends into décor |
Energy Efficiency | Usually rated A or below - higher running costs | Typically rated A++ or A+++ - lower long-term running costs |
Upfront Cost | From ~£200 | From ~£800–£2,000 (including installation) |
Best For | Renters, occasional use, single-room cooling | Homeowners, long-term use, larger or multi-room spaces |
Which is More Energy Efficient in UK Homes?
Wall-mounted air conditioners wipe the floor with portables when it comes to efficiency.
Many modern split systems boast energy ratings of A++ or A+++, indicating superior efficiency. In contrast, portable units often have lower energy ratings, typically around A or below, leading to higher energy consumption for the same cooling output.
Split systems are designed to cool larger spaces more effectively and quietly, making them suitable for open-plan areas or multiple rooms. Portable units, while convenient, are generally less efficient and best suited for smaller spaces.
According to the UK government’s guidance on energy efficiency, improving home insulation and using energy-efficient appliances can lead to significant savings on energy bills. While air conditioning isn’t the primary focus, the principles apply: using more efficient systems reduces energy consumption and costs.
To enhance efficiency further, consider pairing your air conditioning system with a smart thermostat.
These devices allow for better control over your home’s temperature, ensuring that cooling is only used when necessary, thus avoiding unnecessary energy expenditure.
Running Costs: Which Costs More Long-Term?
Let’s talk numbers, based on 2025 electricity prices - currently around 25.73p per kWh according to Ofgem’s summer price cap (valid from 1 July to 30 September 2025).
Here’s how the costs stack up for a 2.5 kW unit running 4 hours a day for 60 summer days:
Portable AC:
Uses 1–1.5 kWh/hour, costing £61.80–£92.40 per year
(Calculation: 1–1.5 kWh × £0.2573 × 4 hours × 60 days)
Wall-Mounted AC:
Uses 0.5–0.8 kWh/hour, costing £30.96–£49.41 per year
(Calculation: 0.5–0.8 kWh × £0.2573 × 4 hours × 60 days)
Over five years, that’s a potential saving of £154–£215 in favour of a wall-mounted system.
“Wall-mounted air conditioners typically just need a quick filter clean once a year, whereas portable units demand far more upkeep - like draining water tanks and frequent filter cleans. That’s why, even with a higher upfront cost, wall-mounted systems tend to be the more wallet-friendly option in the long run.”
— Ben Price, Co-founder of Heatable
How Easy Is It to Install a Portable or Wall-Mounted Air Conditioner?
Portable Air Conditioner:
It’s plug-and-play, plain and simple. Just wheel it into place, pop the exhaust hose out of a window using the included kit, and you’re up and running in minutes.
No tools, no drama. Ideal for renters or anyone avoiding permanent changes to their property.
Wall-Mounted Air Conditioner (Split System):
This one’s strictly for the professionals. Installation involves drilling through walls, running refrigerant pipes, and mounting an outdoor unit - a job that usually costs £300–£800.
It must also meet UK building regulations, so unless you fancy breaking the law (and possibly your wall), leave it to a certified engineer.
Are There Low-Carbon Alternatives?
Air conditioners aren’t exactly Mother Nature’s best mate, but there are cooler ways to stay cool.
One standout option? Air source heat pumps. These clever systems can cool your home in summer and heat it in winter, using a fraction of the energy.
In fact, they’re up to 3–4 times more efficient than traditional ACs, helping you shrink your carbon footprint without breaking a sweat.
Even better, they’re backed by the Boiler Upgrade Scheme, which offers grants of up to £7,500 towards installation if you’re switching from fossil fuel heating.
Not ready to make the switch? If you’re renting or stuck with a portable AC, look for models with an A+ energy rating or higher, and use them smartly - ideally in short bursts rather than running them all day.
And don’t underestimate the power of good insulation.
The Energy Saving Trust highlights that improving your home’s insulation is one of the simplest ways to reduce the need for cooling, meaning lower energy bills and a comfier home year-round.
Ready to Choose the Right Air Conditioner? 🏠❄️
Now you’ve got the full lowdown on portable vs wall-mounted ACs - from energy efficiency and noise levels to costs and carbon impact - you’re in a much cooler position to make the right call for your home.
If you’re ready to invest in a wall-mounted split system, Heatable’s here to help.
Our team can guide you through the pros, cons, and costs - and get you set up with a cooling solution that suits your space, budget, and lifestyle.
Need help deciding? 🆘
Browse our air conditioning options or get in touch with one of our friendly experts. We’ll help you stay cool, stay savvy, and stay energy-smart - all summer long.
