How long does a commercial heat pump installation take?

“How long will it take?” is the first question most facilities managers ask, and the honest answer is: the on-site install is rarely the constraint. What sets the programme is the survey, the electrical supply and — for ground and water-source — the ground works. Here is a realistic breakdown.

Stage 1 — Feasibility and heat-loss survey (1-2 weeks)

We carry out a heat-loss survey, review at least twelve months of gas or oil consumption, survey the emitters, and confirm the incoming electrical supply capacity. This stage sets the sizing, the flow temperature and — critically — whether the electrical supply can take the added load. It is fast, but everything downstream depends on getting it right.

Stage 2 — Design, emitters and DNO (2-6 weeks, overlapping)

We design to the lowest workable flow temperature, specify any selective emitter upgrades, and produce the BS 4142 acoustic assessment and planning position. In parallel, if the added load needs a DNO supply upgrade, we start that process now. This is the step that most often stretches a programme: a supply upgrade can take weeks to many months depending on the network, so starting it at feasibility rather than install week is the single biggest thing an installer can do to keep the project on time.

Stage 3 — Procurement and design freeze (2-8 weeks)

Once the acoustic and planning position is settled and the supply route is confirmed, the design is frozen and plant is ordered. Lead times vary by manufacturer and by system size; larger cascades and high-temperature units sit at the longer end.

Stage 4 — Install and witnessed commissioning

• Air-source: typically 4-12 weeks on site. Plant is largely pre-assembled, so the live boiler cutover is a matter of hours — and we keep the existing boiler live as backup through commissioning, so the building is never without heat.
• Ground-source: longer, because of drilling, a thermal response test and ground works — often several months, ideally programmed around the building’s quiet season.
• Water-source and heat networks: longest, driven by abstraction permits and buried distribution — 12 months or more including design, planning and civils.

Every install ends with a witnessed commissioning: the SCOP verified against design to BS EN 14825, the electrical and F-Gas certification issued, and the O&M pack handed over.

The realistic end-to-end picture

System	Typical end-to-end	Longest-lead item
Air-source retrofit	3-6 months	DNO supply upgrade
Hybrid boiler-replacement	3-6 months	DNO supply / procurement
Ground-source	6-12 months	Drilling & ground works
Water-source / heat network	12 months+	Abstraction permit / civils

The takeaway

If a supplier promises a same-month commercial install without having looked at your electrical supply, be sceptical. A realistic programme is built around the survey, the DNO position and — for ground and water-source — the drilling. Start early, sequence the long-lead items first, and the install itself is the straightforward part.

See our full installation process or read whether a heat pump is worth it for your building. When you are ready, send your consumption data for a free feasibility.