A wall-mounted split air-conditioning unit cooling a UK living room
Independent UK air-conditioning guidance

Straight answers about air conditioning.

No sales pitch, no guesswork — just clear, accurate guidance on how air conditioning works, what it really costs to run, what size you need, the F-gas rules, and how to choose a certified installer. Sourced from gov.uk, the HSE and the Energy Saving Trust.

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In 40 seconds

Air conditioning moves heat out of a room rather than burning fuel to make cold — a refrigerant cycle pumps indoor heat outside. For a UK home the usual choice is a wall-mounted split system (one indoor unit, one outdoor) or a multi-split (several indoor units on one outdoor). A single split typically costs £1,500–£3,000 fitted and a 2.5 kW unit costs roughly 15–25p an hour to run. By law only an F-Gas-certified engineer may install or service equipment containing refrigerant — DIY refrigerant work is illegal. The most useful first step is an accurate sizing survey and a written quote from a certified installer.

£1.5–3k
typical single split system, supplied & fitted
15–25p
rough cost to run a 2.5 kW unit per hour
F-Gas
certification legally required to install or service
0
obligation — the first quote enquiry is free
The answer library

Every question a UK buyer actually asks.

Organised the way you think about it — how it works, what it costs, what size you need, the rules around fitting it, and how to keep it running.

Air conditioning basics

How cooling actually works, the system types, and the difference between a split, a multi-split and a heat pump.

Pillar guide

How does air conditioning work?

The refrigeration cycle that moves heat out of a room, in plain English.

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 Basics

What are the main types of air conditioning?

Split, multi-split, portable, ducted and VRF — how they differ and who each suits.

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 Basics

Split vs multi-split air conditioning: which is right?

One room or several — how the two layouts differ on cost, efficiency and clutter.

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 Basics

Portable vs fixed air conditioning: which is better?

The plug-in box versus the wall-mounted split — honest trade-offs on cost, noise and power.

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 Basics

Air conditioning vs heat pump: what is the difference?

They use the same heat-moving technology — the difference is purpose, water vs air, and grants.

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 Basics

What is ducted air conditioning and how does it work?

The hidden indoor unit and concealed ductwork that condition a whole floor discreetly.

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 Basics

Air conditioning for the home: what you need to know

Choosing, costing and installing domestic air con the sensible way.

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 Basics

How does air con cool a room?

From warm room air to cool, dry comfort — the indoor process explained.

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 Basics

What is inverter air conditioning and why does it matter?

Variable-speed compressors that hold a steady temperature and cut running costs.

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 Basics

What is air conditioning refrigerant and why is it regulated?

The working fluid at the heart of every system — the types, the law and the safety.

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Cost & running cost

What it costs to buy, fit and run — with the kWh arithmetic done honestly, not guessed.

Cost

How much does air conditioning cost in the UK?

The full picture: what you pay to buy, install, run and service a system.

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 Cost

How much does air con installation cost?

What the installation labour includes, and what changes the price.

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 Cost

How much does air conditioning cost to run?

The electricity maths, shown honestly, plus what changes your bill.

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 Cost

Is air conditioning expensive to run?

A straight answer, with the numbers behind it and the comparisons that matter.

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 Cost

How much electricity does air conditioning use?

Capacity versus consumption, in kWh, with worked examples.

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 Cost

What does it cost to run air con per hour?

The per-hour figure, the maths behind it, and what shifts it.

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 Cost

How much does air con servicing cost?

Annual service, re-gas and leak checks — what they cost and why they matter.

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 Cost

How much does multi-room air conditioning cost?

Multi-split pricing, what scales it, and how it compares to several singles.

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 Cost

Air con vs a fan: which is cheaper to run?

The honest cost comparison, and why the two are not really doing the same job.

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 Cost

What is the cheapest way to run air con?

Practical, source-backed habits that lower the bill without losing comfort.

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Choosing & sizing

Getting the capacity right for the room, and reading the energy label before you buy.

Sizing

What size air conditioning do I need?

How cooling capacity is matched to a room — the rough kW-per-square-metre starting point, what pushes it up, and why a proper heat-load calculation is what actually decides it.

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 Sizing

How does an air con BTU calculator work?

What BTU means, how it converts to kW, and why an online BTU calculator is only ever a starting estimate, not a specification.

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 Sizing

What is the best air conditioning for a home in the UK?

How to weigh up the main home cooling options — fixed splits, multi-splits and portables — against cost, efficiency, noise and how many rooms you want to cool.

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 Sizing

What is the quietest air conditioning?

How air-con noise is measured, why fixed split units are far quieter than portables, and what to check on a datasheet before you buy.

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 Sizing

What is the most energy efficient air conditioning?

How efficiency is measured with SEER and SCOP, what the A+++–D energy label means, and why an inverter split is the efficient choice for a UK home.

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 Sizing

What is the best air conditioning for a bedroom?

Why a quiet, correctly-sized inverter split suits a bedroom best, and how noise, night modes and positioning affect a good night’s sleep.

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 Sizing

What air conditioning do I need for a conservatory?

Why conservatories are the hardest room to cool, how the heavy glazing pushes the heat load up, and what that means for sizing and choosing a unit.

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 Sizing

Can air conditioning heat as well as cool?

How a reversible air conditioner works as a heat pump, why it can heat efficiently, and what the SCOP rating tells you about winter running cost.

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 Sizing

How does the air conditioning energy rating work?

What the A+++–D energy label means, how SEER and SCOP set the grade, and how to use the label to compare running costs before you buy.

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 Sizing

How do I choose an air conditioning brand?

Why the installer and the unit’s specification matter more than the badge, and how to compare brands on efficiency, noise, warranty and parts support.

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Installation & regulations

The F-gas law, planning and building regs — what’s legal, what’s notifiable and what needs a certified engineer.

Install

How is air conditioning installed?

From survey to commissioning — what really happens when a split system goes in.

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 Install

Do you need planning permission for air conditioning?

When a domestic outdoor unit is permitted development — and when it is not.

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 Install

What are the F-Gas regulations for air conditioning?

The refrigerant law that decides who may touch your system — and why.

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 Install

What certification should an air con installer have?

How to check an engineer is legally qualified before you let them touch refrigerant.

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 Install

Can I install air conditioning myself?

Where DIY ends and the law begins — including ‘pre-charged’ split kits.

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 Install

What are the electrical requirements for air conditioning?

Dedicated circuits, isolation and Part P — the wiring side of an install.

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 Install

Where should air conditioning units be positioned?

Getting the indoor and outdoor positions right for airflow, noise and the rules.

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 Install

How long does air conditioning installation take?

From a half-day single split to multi-day multi-split jobs — what drives the timing.

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 Install

Do building regulations apply to air conditioning?

Part P, ventilation and energy — where the Building Regulations touch an install.

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 Install

Can you fit air conditioning in a rented property?

What tenants, landlords and leaseholders need to agree before anything is fitted.

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Servicing, problems & decisions

Keeping a system healthy, diagnosing the common faults, and choosing the right installer.

Servicing

Air-con servicing explained

What a proper air-conditioning service actually involves, why it protects efficiency and warranty, and what the law requires on refrigerant leak-checks.

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 Servicing

How to get an air-con quote

How to find the right F-Gas-certified installer, what a proper quote should contain, and the questions that separate a good fitter from a cheap one.

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 Servicing

How often should you service air conditioning?

How often a domestic and commercial system needs servicing, what drives the interval, and the separate legal F-gas leak-check schedule.

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 Servicing

Why is my air-con not cooling?

The common reasons an air-conditioner runs but doesn’t cool, which you can safely fix yourself, and which need a certified engineer.

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 Servicing

Why does my air-con smell bad?

What different air-con smells mean — musty, vinegary, eggy or burning — what causes them, and which ones mean switch it off now.

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 Servicing

Why is my air-con leaking water?

Why an indoor air-con unit drips water, the most common causes, and which you can clear yourself versus what needs an engineer.

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 Servicing

Air-con re-gas explained

What re-gassing actually means, why a system going low almost always has a leak, what it costs, and why only certified engineers may do it.

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 Servicing

How long does air conditioning last?

The realistic lifespan of an air-con system, what makes it last longer or fail sooner, and how to judge repair versus replacement.

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 Servicing

Air-con maintenance tips

The simple jobs that keep an air-con system efficient and reliable, what to leave to a certified engineer, and why both matter.

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 Servicing

Air-conditioning FAQs

Quick, accurate answers to the questions people ask most about cost, running cost, the law, servicing and lifespan — with links to the full guides.

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How it works

From hot room to a clear quote, in three steps.

You don’t need to know which system or size you need before you enquire. That’s the installer’s survey job.

  1. Tell us about the space. A short, no-obligation enquiry — the rooms you want cooled, the building type, and whether you want cooling only or heating too.
  2. Get matched to an F-Gas-certified installer. We connect you with a certified installer who surveys the property, does a proper heat-load calculation and sizes the system correctly.
  3. Compare a clear written quote. They set out the system, the capacity, the install scope and the cost — with no obligation to proceed.

Thinking about air conditioning?

Get it sized and quoted properly by an F-Gas-certified installer. It’s free to enquire, there’s no obligation, and an accurate heat-load survey is what stops you buying the wrong system.

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