Guide · Installation timelines

How long does commercial AC installation actually take?

Real UK timelines by scope — survey, design, install and commissioning — plus the four things that always cause delay, and how to run them in parallel.

install-timeline
In short

A typical 4-zone office AC install runs 4–6 working days on site after a 1-week design and 3–6-week landlord L4A — end-to-end 6–10 weeks. Single splits take a day. Whole-building VRF takes 3–6 weeks on site.

Timeline by scope

Working days on site, and the phases around them.

ScopeSurveyDesignInstallCommission
Single wall-mount split (one room)1 day2–3 days1 daySame day
4-way cassette, single office1 day3–5 days1–2 days0.5 day
Multi-split, 4 zones (200 m² floor)1 day1 week4–6 days1 day
VRF, single floor (250 m²)1–2 days1–2 weeks7–10 days1–2 days
VRF, whole building (1,000 m²+)2–3 days3–4 weeks3–6 weeks3–5 days
Server room CRAC (with N+1)1 day1–2 weeks3–5 days1 day
The four delay causes

The things that push a 6-week job to 12.

  • Landlord Licence for Alterations

    L4A negotiation is the single biggest hidden delay — 3–6 weeks is typical, longer if the landlord's surveyor requests a structural sign-off. Start it the day the design is signed off, not after.

  • Long-lead equipment

    Standard Daikin cassettes and splits: 2–3 weeks. Higher-capacity VRV condensers and specialist CRAC units: 6–10 weeks. Confirm lead time at quote — not at PO.

  • Planning consent for condensers

    Rooftop condensers in a conservation area or on a listed building need planning — 8 weeks minimum. Ground-floor condensers rarely do. AccuTemp flags this in the initial site survey.

  • Building access windows

    Out-of-hours installs on live floors are efficient but sensitive to shared risers, security escort availability and neighbour restrictions. Confirm access windows before locking a start date.

Related: office installation process, cost guide, VRF vs split, sizing guide, emergency response.

Timeline FAQs

What clients ask before locking a start date.

How long does commercial AC installation take?
For a typical UK commercial office, the installation itself takes 4–6 working days for a 4-zone system covering a 200 m² floor. Add 1 week for survey and design, and 3–6 weeks for landlord Licence for Alterations. End-to-end, from first contact to commissioning, a routine office fit-out lands at 6–10 weeks.
How long does a VRF system take to install?
A single-floor VRF (~250 m²) takes 7–10 working days on site. Whole-building VRF across 1,000 m² or more typically runs 3–6 weeks depending on riser access and simultaneous trades. Programmed weekend and out-of-hours work is standard.
How quickly can you install AC in an emergency?
For emergency replacement — a failed system in a data centre or trading environment — AccuTemp can be on site within 4 hours (SLA customers) and running temporary cooling within 24 hours, with permanent replacement inside 5–10 days depending on equipment availability.
What's the biggest cause of delay?
Landlord Licence for Alterations. It's a fixed 3–6 week negotiation and it can't be compressed. Second is condenser planning consent in conservation areas or on listed buildings — 8 weeks minimum. Start both in parallel with the design, not after.
Can commercial AC be installed while the office is in use?
Yes. We routinely install on live floors — brazing and refrigerant work happen out-of-hours, cassette drops and controls commissioning during standard hours. Occupants generally lose access only to the specific meeting room being worked on that day.
Need a firm date

Book a scoping call — we'll issue a Gantt with your quote.

Book a scoping callPrefer to message? WhatsApp us
Contact usWhatsApp