Air Conditioning Installation Sussex
Expert installation, repair & maintenance across Sussex & Surrey
Expert Air Conditioning Installation
Looking for expert air conditioning installation? At Ernest Air Cooling, we provide affordable, high-quality air conditioning solutions for homes and businesses across the South East—from Central London to Brighton and beyond.
With over 20 years of hands-on experience, we've built a reputation for reliability, efficiency, and top-tier workmanship. All our systems are reverse-cycle heat pumps, providing efficient cooling in summer and heating in winter—up to 3-4 times more efficient than electric heaters. Whether you're cooling a single room or an entire property, we'll design and install a system that suits your needs and your budget.
What We Offer:
- Energy-Efficient & Whisper Quiet
A+++ rated systems costing just £40-£80/year to run, with indoor noise levels as low as 19dB—quieter than a whisper
- Premium Brands
Certified installer for Daikin, Mitsubishi Electric, Samsung, Toshiba and more
- Expert Installation
Professional installation with smart, discreet unit placement
- Comprehensive Service
From initial design to installation and ongoing maintenance
Daikin Authorised Dealer
We are proud to be an authorised Daikin dealer, offering the full range of Daikin air conditioning systems with manufacturer-backed warranties and expert installation.
Comprehensive Air Conditioning Services
From initial consultation to ongoing maintenance, we provide complete air conditioning solutions
Installation Services
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Residential Installation
Complete home cooling solutions from single room to whole-house systems
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Commercial Systems
specialised cooling for offices, retail, restaurants and industrial spaces
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specialised Environments
Climate control for server rooms, wine cellars, and temperature-sensitive environments
Maintenance & Support
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Repair Services
Fast, reliable repairs for all air conditioning brands and systems
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Preventative Maintenance
Regular servicing to ensure optimal performance and system longevity. Our AC maintenance packages start from just £75/year.
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Emergency Call-Outs
Responsive service when you need emergency air conditioning repairs
Which AC System Is Right for You?
Not all air conditioning systems are the same. Here's how the main types compare so you can choose the best fit for your property.
| Feature | Wall-Mounted Split | Multi-Split | Ceiling Cassette | Ducted System | Floor-Standing |
|---|---|---|---|---|---|
| Best For | Single rooms, bedrooms, home offices | 2-5 rooms from one outdoor unit | Offices, shops, restaurants | Whole-house or large commercial | Conservatories, rooms with no wall space |
| Room Size | 10-45m² | Multiple rooms up to 150m² total | 20-80m² | Whole property 100m²+ | 15-50m² |
| Indoor Noise | 19-42 dB | 19-42 dB per unit | 26-38 dB | 25-35 dB (grilles only) | 22-44 dB |
| Energy Rating | Up to A+++ | Up to A+++ | Up to A++ | Up to A++ | Up to A++ |
| Installation Time | 1 day | 1-2 days | 1-2 days | 2-5 days | 1 day |
| Price (Installed) | £1,599 - £2,500 | £3,500 - £8,000 | £2,500 - £4,000 | £5,000 - £12,000+ | £1,800 - £3,000 |
| Heating Mode | Yes - heat pump | Yes - heat pump | Yes - heat pump | Yes - heat pump | Yes - heat pump |
| Visibility | Wall unit visible | Wall units in each room | Flush with ceiling | Completely hidden | Freestanding unit visible |
| Running Cost/Year | £40-£80 | £80-£200 | £60-£120 | £150-£400 | £50-£100 |
Wall-Mounted Split
Most popular for homes
Multi-Split System
Multiple rooms, one outdoor unit
Ceiling Cassette
Commercial & open-plan spaces
Ducted System
Completely hidden, whole-property
Floor-Standing
Easy install, no wall mounting
Our Recommendation
For Most Homes:
A wall-mounted split system is the most cost-effective choice for cooling a single room. If you need multiple rooms, a multi-split system keeps things neat with just one outdoor unit.
For a Premium Finish:
A ducted system is completely hidden behind ceilings with only discreet grilles visible—the preferred choice for new builds and renovations where aesthetics matter. Not sure what size you need? Try our free BTU calculator.
How Much Does Air Conditioning Cost to Run?
Modern AC systems are far cheaper to run than most people expect. Here's what it actually costs.
Cooling Only
£40 - £80
per room, per year
Based on a 2.5-3.5kW wall-mounted split system running 4-6 hours daily during summer months (June-September). With current electricity rates at ~24p/kWh.
Heating Mode
3-4x
more efficient than electric heaters
Heat pump AC produces 3-4kW of heat for every 1kW of electricity. Heating a room costs roughly £0.06-0.08/hour — compared to £0.24/hour for a standard electric heater.
vs Gas Boiler
Comparable
pence per kWh of heat output
Gas costs ~7p/kWh but boilers are 90% efficient, so ~7.8p per kWh of heat. Heat pump AC at 24p/kWh electricity with a COP of 3.5 gives ~6.9p per kWh of heat — actually slightly cheaper.
The Real Numbers
A typical Daikin or Mitsubishi wall-mounted unit running in a bedroom or living room costs roughly 11-16p per hour to cool and 6-8p per hour to heat. For a household using AC moderately (4-6 hours daily in summer, occasional heating in spring/autumn), expect an annual electricity cost of £40-£80 per room. That's roughly the same as running a fridge.
Costs based on UK average electricity rate of 24p/kWh. Actual costs depend on usage, room size, insulation, and tariff. Systems with A+++ ratings will be at the lower end.
Our Installation Process
From first enquiry to enjoying cool air — here's exactly what to expect
Free Survey & Quote
We visit your property, measure the rooms, assess insulation, window orientation, and heat sources. You get a detailed written quote within 48 hours — no obligation, no pressure.
System Design
We specify the right unit size using heat load calculations (not guesswork), choose the best indoor unit position for airflow, and plan the pipework and condenser location to keep things neat.
Installation Day
We mount the indoor unit, fix the outdoor condenser on anti-vibration pads, run pipework through a small 65mm hole in the wall, connect refrigerant lines, and wire everything up. Most single-room installs are done in one day.
Testing & Handover
We vacuum the system, check for leaks, commission the unit, and test cooling and heating modes. We walk you through the controls, set up Wi-Fi if applicable, tidy up, and leave you with a clean, working system and a 5-year warranty.
Air Conditioning for Heating Too
Every system we install is a reverse-cycle heat pump — meaning it heats just as effectively as it cools. In fact, many of our customers use their AC as their primary heating source in spring and autumn.
Heat pump AC produces 3-4 kW of heat for every 1 kW of electricity, making it 3-4 times more efficient than a standard electric heater and comparable in cost to a gas boiler — at around 6-8p per hour of heating.
Get a Heating & Cooling QuoteHow It Works
In heating mode, the system reverses its refrigerant cycle — extracting heat from outdoor air (even at temperatures down to -15°C) and pumping it inside. It's the same technology as ground-source heat pumps, just more affordable to install.
When to Use It
AC heating is ideal for shoulder seasons (March-May, September-November) when you don't want to fire up the full central heating. It's also excellent as supplementary heating for rooms that are always cold — conservatories, extensions, home offices, and bedrooms above garages.
Cost Comparison
Electric heater: ~24p/hour | Gas boiler: ~8p/hour | Heat pump AC: ~7p/hour — the cheapest option per kWh of heat delivered.
Certified Installer of Leading Brands
We install and service the industry's most reliable air conditioning systems
As an authorised Daikin dealer and certified installer for these leading manufacturers, we offer extended warranties and manufacturer-backed support for all our air conditioning installations throughout Sussex and the South East.
What Our Clients Say
"Exceptional service from start to finish. Tim recommended the perfect air conditioning system for our home in Brighton. Installation was quick, tidy, and the system works beautifully. Highly recommend Ernest Air Cooling!"
Sarah Thompson
Residential Customer, Brighton
"We needed air conditioning for our office in Horsham and Ernest Air Cooling delivered exactly what we needed. The team was professional, knowledgeable, and completed the installation with minimal disruption to our business."
Mark Richardson
Business Owner, Horsham
Frequently Asked Questions
Common questions about air conditioning installation and services in Sussex
How much does air conditioning installation cost in Sussex?
Air conditioning installation costs vary depending on the system type, number of units, and complexity of installation. For a single room split system, prices typically start from £1,599 including installation. We provide detailed, no-obligation quotes after assessing your space and needs.
How long does air conditioning installation take?
Installation timeframes vary by project scope. A standard single room split system typically takes 1 day to install. Multi-split systems serving 2–4 rooms usually take 1–2 days, while larger commercial installations may require 3–5 days or more.
Do I need planning permission for air conditioning in Sussex?
In most cases, domestic air conditioning installations don't require planning permission as they fall under permitted development. However, there are exceptions for listed buildings or conservation areas. We can advise on planning regulations specific to your property.
How energy efficient are modern air conditioning systems?
Modern air conditioning systems are highly energy efficient, with many units achieving A+++ energy ratings. The systems we install use inverter technology that can reduce energy consumption by up to 30–50% compared to older units.
Can air conditioning heat as well as cool?
Yes, all the systems we install are reverse-cycle heat pumps that provide both cooling in summer and efficient heating in winter. They are up to 3-4 times more efficient than electric heaters, meaning for every 1kW of electricity used, they produce 3-4kW of heat. This makes them an excellent year-round climate solution and a cost-effective alternative to traditional heating.
How much does air conditioning cost to run per year?
A typical wall-mounted split system costs between £40-£80 per year to run for an average room, based on moderate use. Modern inverter systems from Daikin and Mitsubishi Electric are exceptionally efficient, with A+++ energy ratings that keep running costs low. The exact cost depends on usage patterns, room size, and electricity tariff.
How noisy are modern air conditioning units?
Modern air conditioning indoor units are remarkably quiet. Daikin systems operate as low as 19dB on their lowest setting—quieter than a whisper (30dB) or a library (40dB). Outdoor units typically run at 45-50dB, comparable to light rainfall. We position outdoor units carefully to minimise any impact on you or your neighbours.
What size air conditioning unit do I need for my room?
As a rough guide, you need approximately 150 watts of cooling per square metre. A typical bedroom (12-15m²) needs a 2.5kW unit, while a large living room (25-30m²) may need a 5kW unit. However, factors like ceiling height, insulation, sun exposure, and number of windows all affect sizing. Try our free BTU calculator for an instant estimate, or we can carry out a free on-site survey to calculate the exact requirement for your space.
Can I install air conditioning in a listed building or conservation area?
Yes, it's possible in most cases. Listed buildings require Listed Building Consent, and conservation areas may have restrictions on visible external equipment. We specialise in discreet installations using rear placement, concealed pipework, and in some cases systems with no outdoor unit at all. Read our full guide to AC in listed buildings.
How long do air conditioning systems last?
A well-maintained air conditioning system typically lasts 15-20 years. Premium brands like Daikin and Mitsubishi Electric are known for exceptional longevity. Regular annual servicing is the single biggest factor in extending system life — our maintenance packages help keep your system running at peak performance for years.
Will air conditioning add value to my home?
Yes. Air conditioning is increasingly viewed as a desirable feature in UK homes, particularly in southern England where summer temperatures are rising. Estate agents report that AC can add 3-5% to a property's value, and it's a strong selling point for home offices and south-facing rooms. As a heat pump, it also supports your property's energy efficiency credentials.
Do you offer finance or payment plans for AC installation?
We offer flexible payment options to make air conditioning installation accessible. Contact us to discuss payment arrangements that suit your budget. All our installations come with a 5-year guarantee as standard, giving you peace of mind whatever payment option you choose.
Not Sure What Size AC You Need?
Use our free BTU calculator to get an instant recommendation based on your room size, insulation, and environment.
Air Conditioning Insights & Projects
Ernest Air Cooling Becomes Daikin Authorised Dealer
What our official Daikin partnership means for Sussex customers.
Luxury AC Installation in Kingston
Multi-room Mitsubishi system for a premium residential property.
No Outdoor Unit AC in Soho, London
How we solved AC installation without an external unit in central London.
Ready for Expert Air Conditioning in Sussex?
Whether you're looking to cool a single room or need a complete commercial system, our team is ready to deliver the perfect air conditioning solution for your space and budget.