How long does a commercial air conditioning installation take?
Updated 23 October 2026 · SEO Dons Editorial
Why is there no standard installation time?
A single split on an outside wall and a chiller lifted onto a roof share a name and little else. Each project is a chain of stages with different owners: the client, a landlord, the council, the network operator, the installer and the commissioning engineer. Several stages run before anyone is on site, and some run in parallel. This guide therefore describes the stages and what decides each one, and gives a time only where an official page states it.
What are the stages, and what decides each?
| Stage | What decides it | Clock set in law or by an operator |
|---|---|---|
| Survey and design | Number of zones, access to ceiling voids and plant areas, how much load must be measured. The sizing guide covers the calculation. | None stated |
| Lease and landlord | The lease. Where it forbids improvements without consent, consent is not to be unreasonably withheld (Landlord and Tenant Act 1927, section 19(2)). | None stated |
| Planning | Whether plant is fixed to the outside, which Lewisham Council says needs planning permission, and the council's caseload. The planning guide covers the test. | England: 8 weeks for most applications, 13 for major development, 16 where an environmental impact assessment applies, unless a longer period is agreed in writing |
| Electrical capacity | Whether the supply can carry the load, and the network operator's process. See electrical capacity for new plant. | Quotation standards from 5 working days for a single-phase service to 65 for extra high voltage. Northern Powergrid says connections are typically completed within 90 days of accepting its offer, depending on the work. |
| Equipment | Supplier lead times, quoted at order | None stated |
| Pre-start checks | An asbestos survey with the area vacated, pre-construction information, and HSE notification on larger jobs | Survey completed before work starts. Notification above 30 working days with more than 20 workers at once, or 500 worker days. |
| Installation | Phasing, access hours, lifting plans and road space | Lifts planned by a competent person. A council can specify working hours for noisy works and restrict road use for works on or near a road. |
| Commissioning and handover | Testing, balancing, controls and records. See the commissioning and handover guide. | Commissioning notice within five days or 30 days of the work, depending on route. Owner's information within five days of completion. |
The electrical row needs a note. Under the Electricity (Connection Standards of Performance) Regulations 2015, a distributor must pay if it fails to dispatch a quotation within the prescribed period: 5 working days for a single-phase service connection, 15 for a small project, 25 for other low voltage demand, 35 for high voltage and 65 for extra high voltage. After acceptance of a small project quotation the distributor has 7 working days to contact the customer to agree dates, and the works are then due by the agreed date. These are standards for the operator's own steps, not a project duration.
For example, in a hypothetical office needing planning permission for a roof condenser and a larger supply, the council's period and the operator's quotation period run in parallel, so the programme follows whichever is longer. Neither includes the equipment, the works or the commissioning.
How do size and system type change the programme?
| Project | What the sources attach to it |
|---|---|
| Single split | An outdoor unit fixed to the wall brings in planning and the lease. Every other stage still applies, with fewer rooms to survey, route and commission. |
| Multi-room office | Pipe and drain routes through ceilings and risers, so the asbestos survey and area-by-area phasing carry weight. See the retrofit guide. |
| VRF floor | A larger electrical load (see the electrical supply guide), many indoor units to commission and, above HSE's thresholds, notification. |
| Chiller replacement | Heavy lifts needing a planned lift and possibly road space, and chilled-water commissioning to CIBSE Code W and BSRIA's BG 2/2010. Replacing old plant is covered on the air conditioning replacement page. |
How do phased installs in an occupied building work?
A phased install sequences the work by area. HSE's CDM guidance says contractors must plan, manage and monitor their work taking into account the risks to anyone who might be affected, and that commercial clients must provide pre-construction information to every designer and contractor bidding for or appointed to the work, which is where access hours and protected areas belong. A refurbishment asbestos survey involves destructive inspection, so the area must be vacated while it is done. The person responsible for fire safety must review the fire risk assessment when the premises or technical measures change significantly.
Handover can be phased too. BSRIA's Soft Landings framework describes graduated handover so operators have more time to understand interfaces and systems before occupation. CIBSE's Code M puts fine tuning and seasonal testing in the in-use stage, after the first handover.
How should a quoted programme be read?
Ask for each stage to appear separately, with the owner of every dependency named: the landlord's consent, the planning decision, the network operator's offer and equipment delivery. Check that commissioning is its own stage rather than slack at the end, because the Part L notice depends on test results. Check what the programme assumes about access hours, lifts and road space. Readers planning a project can see the commercial air conditioning installation page and send an enquiry through the site's form.
Sources
- Determining a planning application (Planning Practice Guidance), MHCLG (GOV.UK), checked 22 October 2026
- Electricity (Connection Standards of Performance) Regulations 2015, Schedule 1, legislation.gov.uk, checked 22 October 2026
- Electricity (Connection Standards of Performance) Regulations 2015, regulation 2, legislation.gov.uk, checked 22 October 2026
- Electricity (Connection Standards of Performance) Regulations 2015, regulation 6, legislation.gov.uk, checked 22 October 2026
- Electricity (Connection Standards of Performance) Regulations 2015, regulation 8, legislation.gov.uk, checked 22 October 2026
- Small connections, Northern Powergrid, checked 22 October 2026
- Road Traffic Regulation Act 1984, section 14, legislation.gov.uk, checked 22 October 2026
- Control of Pollution Act 1974, section 60, legislation.gov.uk, checked 22 October 2026
- Lifting Operations and Lifting Equipment Regulations 1998, regulation 8, legislation.gov.uk, checked 22 October 2026
- Landlord and Tenant Act 1927, section 19, legislation.gov.uk, checked 22 October 2026
- Planning: frequently asked questions (business), Lewisham Council, checked 22 October 2026
- Find out if asbestos could be present in your building, HSE, checked 22 October 2026
- Arrange an asbestos survey, HSE, checked 22 October 2026
- Commercial clients: roles and responsibilities, HSE, checked 22 October 2026
- Contractors: roles and responsibilities, HSE, checked 22 October 2026
- Regulatory Reform (Fire Safety) Order 2005, article 9, legislation.gov.uk, checked 22 October 2026
- Approved Document L Volume 2, 2021 edition incorporating 2023 amendments, MHCLG (GOV.UK), checked 22 October 2026
- Commissioning Code M: Commissioning management (2022), CIBSE, checked 22 October 2026
- CIBSE Commissioning Codes, CIBSE, checked 22 October 2026
- Commissioning Water Systems (BG 2/2010), BSRIA, checked 22 October 2026
- What stages are involved on a Soft Landings project?, BSRIA, checked 22 October 2026
Common questions
Does the 8 week planning period fix the decision date?
No. The statutory limit is 8 weeks for most applications and 13 for major development, with 16 where an environmental impact assessment applies, but a longer period can be agreed in writing. The periods also apply to a valid application, so preparing it falls outside them. If a valid application is not decided in time, the applicant has a right to appeal against non-determination.
Do the network operator's quotation periods include the building work?
No. They are standards for sending a quotation, from 5 to 65 working days by connection type. Work comes after the offer is accepted, when the regulations expect dates to be agreed and the works completed by the agreed date. Northern Powergrid says typical completion is within 90 days of acceptance, depending on complexity.
Can installation start before the asbestos survey?
Not where the work will disturb the fabric of the building. HSE says installation or refurbishment work of that kind needs a more intrusive survey completed before work can start, and the area must be vacated while it is done.
Related guides
Ask for commercial HVAC quotes
SEO Dons Ltd publishes this site and replies to every enquiry by email. It does not install, service or maintain HVAC.