How to Quote and Run an Air Conditioning Installation

What you will learn

• Why a proper site survey and heat load calculation is essential before quoting - and what happens when you skip it.
• How to itemize an AC installation quote so every cost line is covered and nothing is absorbed on the day.
• The F-Gas Regulations and Building Regulations compliance steps that must be completed before handover.
• How to run the installation day in sequence to avoid the most common causes of callbacks and margin loss.
• What to include in a commissioning record and F-Gas certificate to protect yourself legally and set up recurring service revenue.

Air conditioning installation is one of the fastest-growing trades in the UK. Demand for split systems, multi-split configurations, and commercial VRF installations has risen steadily as hotter summers drive both residential and commercial buyers to act. But winning the enquiry is the easy part. A quote built on assumptions instead of a heat load survey, a commissioning step compressed under schedule pressure, or an F-Gas certificate that never makes it to the customer - any one of those can turn a solid margin into a breakeven job. This guide walks through the full process from site survey to handover, covering every stage where margin is won or lost.

What the Site Survey Must Establish

A phone enquiry tells you the system type a customer thinks they want. The site survey tells you what the job actually involves. Every quote worth handing over starts here.

Four things need to be established before you price:

Cooling load. The rule of thumb - 0.1 kW of cooling capacity per square metre of floor area - is a starting point, not a substitute for a proper heat load calculation. South-facing rooms, offices dense with computers and equipment, and properties with poor insulation can push the requirement 20-40% higher. Undersizing is the most common technical error in residential AC installation. The customer ends up with a system that cannot hold temperature on the hottest days, and the callback lands back with you.

Installation complexity. Measure the pipe run between the proposed indoor unit position and the outdoor condenser location. Every additional metre of refrigerant pipework adds materials and time. A clean internal route with a short external run is a different job from a four-storey building with solid walls and no existing cable routes. Note the drilling requirements, the pipework routing, and whether trunking is needed for a clean finish.

Electrical capacity. AC units require a dedicated circuit. Confirm the existing consumer unit can accommodate this before you price. If an upgrade or new circuit board is needed, that is a separate cost that must appear in the quote as a line item - not be absorbed into the installation.

Planning position. Reversible heat-pump units (those that both heat and cool) are typically Permitted Development for most UK homes and commercial premises. Cooling-only systems always require planning permission. Flats, listed buildings, and conservation areas have additional restrictions regardless of system type. Confirming the planning position at survey prevents a situation where equipment has been ordered and a planning issue surfaces on installation day.

Building an Accurate Quote

The most common quoting failure in AC installation is treating it as a two-line exercise: unit cost plus a day's labour. Every cost line that isn't in the quote is a cost the installer absorbs.

A complete quote should itemize:

Indoor and outdoor units. Specify brand, model, capacity in kW, and refrigerant type. R32 is now the standard for new installations. R410A is being phased down and should not be quoted for new systems.

Refrigerant pipework. Price by metre, including insulation. This is a material cost with a meaningful price per run - a 10-metre pipe run is a cost that disappears from margin if it is bundled into labour.

Condensate drain. Length of run and whether a condensate pump is required. If gravity drainage is not possible to a suitable outlet, a pump adds cost and complexity that should be in the quote, not discovered on site.

Trunking and fixings. Where pipework needs to be concealed, trunking is a separate materials and labour cost. A customer who expects a clean finish without visible pipework needs this in the quote from the start.

Electrical connection. State explicitly whether the quote includes the Part P electrical connection. If you are making the connection yourself, include it. If a sub-contracted electrician is needed, include that cost or note clearly that it is outside the quote scope.

Commissioning and F-Gas certification. This is a defined, billable task. It includes evacuating the pipework, releasing refrigerant, pressure testing, recording operating data, and issuing the F-Gas certificate. Installers who do not line-item commissioning compress their margin on every job.

Consumer unit work (if required). Quote separately and clearly labelled so the customer understands what this is and why it is needed.

For residential single-split systems, Q2 2026 installed prices from F-Gas registered installers range from £1,500 to £3,000. Multi-split configurations covering three to four rooms run £3,500 to £7,000. Commercial VRF and ducted systems range from £6,000 upward, with larger projects reaching £20,000 or more. London and the South East typically run 20-30% above the national average on labour costs. Quoting accurately within these ranges protects margin - quoting below them and hoping the job comes in under your estimate does not.

Managing the Installation Day

Single-split residential installations run 4-8 hours. Multi-split systems take 1-3 days. Commercial VRF projects typically run 3-5 days depending on the number of indoor units and the extent of the electrical and pipework infrastructure.

Before any work starts on the day:

1. Check the equipment delivery against the order. A missing component on installation day means a delay that costs you more than the part is worth in rescheduling time and customer trust.
2. Confirm the electrical arrangements. If you are completing the Part P connection, confirm your certification and notification route. If a sub-contracted electrician is attending, confirm their arrival window before the customer calls asking where they are.
3. Walk the pipe route and unit positions with the customer before drilling starts. They need to agree to where holes are going in their walls before the work begins.
4. Fix the indoor unit on the wall bracket and drill the core through the wall for the pipework and power cable.
5. Mount the outdoor condenser on the bracket or ground frame. From May 2026, the permitted noise standard tightens to 37 dB LAeq measured at the nearest neighbour's window or door. Confirm the proposed siting meets this before the unit goes up.
6. Run the refrigerant pipework and condensate drain between the indoor and outdoor units. Insulate all refrigerant pipework, including sections hidden within trunking.
7. Complete the electrical connection to Part P standards, including the dedicated circuit from the consumer unit.
8. Pressure test the pipework before releasing refrigerant. A leak found at this stage takes 30 minutes to fix. A refrigerant leak found by the customer six weeks after handover means a full return visit at your cost.
9. Evacuate the pipework, release or top up the refrigerant charge, and commission the system. Record operating pressures, check airflow from each indoor unit, and verify all modes (cooling, heating, fan, dry).
10. Demonstrate controls to the customer: remote operation, mode switching, timer settings, and filter cleaning. A customer who understands their system generates fewer unnecessary service calls.

Commissioning Records and F-Gas Compliance

Commissioning is not turning the unit on and handing over the remote. Done correctly, it is a documented verification process that confirms the installation meets the manufacturer specification and UK F-Gas Regulations.

Every installation involving a fluorinated refrigerant - which covers all R32 and R410A systems - must produce an F-Gas certificate. This is a legal document. The customer must receive it at handover and you must retain a copy.

Your commissioning record should document:

• System details: brand, model, refrigerant type and total charge weight
• Pipework pressure test result, method, and test duration
• Refrigerant charge weight and any top-up quantity added at commissioning
• Suction and discharge operating pressures at commissioning
• Airflow verification for each indoor unit
• Date of commissioning and the attending engineer's REFCOM registration number

The engineer completing the commissioning must hold a valid Level 3 F-Gas qualification (for example, City and Guilds 2079) and the business must be registered with an approved scheme such as REFCOM. This is a legal requirement, not a recommendation. Installing and commissioning refrigerant systems without registration voids the manufacturer warranty and creates a compliance liability.

For commercial installations with an effective rated output above 12 kW, TM44 applies. These systems must be independently inspected at least every five years under the Energy Performance of Buildings Regulations. Flagging this to a commercial customer at handover demonstrates industry knowledge and positions you well when the first inspection date approaches.

Protecting Margin Across the Job

The margin risks in AC installation are consistent and predictable. They show up in the same places on nearly every job.

Underestimated pipe runs. Three extra metres of refrigerant pipework is not expensive when priced - it is expensive when it was not in the quote. Measure the pipe route precisely during the survey, including any vertical drops or rises between floors.

Consumer unit work absorbed into the job. When the survey identifies that a consumer unit upgrade is needed, this should appear as a separate, clearly labelled line in the quote. It frequently gets missed on residential surveys and becomes a job-day negotiation the customer was not expecting.

Commissioning compressed to hit an end time. Commissioning takes time. Pressure testing requires a minimum dwell period to confirm integrity. Installers who rush through commissioning to finish early create callbacks and F-Gas compliance gaps. Build the time in, charge for it, and do it properly.

F-Gas certificates issued late. The commissioning record and F-Gas certificate should be completed on the day and given to the customer before you leave. A certificate chased three weeks later leaves the customer without a valid warranty record and creates a compliance gap in your own documentation.

No maintenance agreement offered. Annual servicing for a single residential split system costs £70-£150 per unit. A customer who receives a passing mention of servicing at handover will search for the cheapest option online next year. A maintenance agreement signed at handover brings them back to you, protects their warranty, and provides recurring revenue that stabilizes cash flow.

The businesses that consistently protect margin in AC installation do the same things: they survey before quoting, they itemize every cost line, they treat commissioning as a documented process, and they leave every customer with complete paperwork and a clear servicing arrangement. The process is not complex - but it has to be followed on every job.

• Air Conditioning Installation UK 2026 | Costs, Sizing, Brands & Free F-Gas QuotesBestBuilders · accessed 2026-06-21
• Commercial Air Conditioning Installation Services UK GuideAircon Group · accessed 2026-06-21
• How Commercial Air Conditioning Installation Works in New Build & Fit-Out ProjectsComplete Cooling Services · accessed 2026-06-21
• HVAC Profit Margins | 2026 Industry BenchmarksSteph's Books · accessed 2026-06-21
• Best Job Costing Software For HVAC Businesses 2026MyQuoteIQ · accessed 2026-06-21

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