Air-source is the workhorse of commercial heat-pump installation. The plant is largely factory-assembled, so the on-site work is groundworks for a compound or plant deck, craneage, the refrigerant and hydraulic connections, controls and commissioning, rather than a build-up from components. For most UK commercial buildings with somewhere sensible to site the units, it is the right answer: quick, low-disruption, and scalable from a single office to a large mixed-use site through cascaded modules.
The engineering that decides whether it works happens before the plant arrives. The heat-loss survey and emitter survey set the flow temperature for the best SCOP, the incoming electrical supply is confirmed as able to take the added load, and the BS 4142 acoustic position and siting are settled. Get those right and the physical install is short and low-risk; get them wrong and the system trips to backup on the coldest day or draws a noise complaint after commissioning.
How air-source heat pump is installed
Delivery runs: prepare the compound base or roof plant deck with anti-vibration mounts and the acoustic screening designed at feasibility; crane the units into position with the airflow and defrost drainage clearances the manufacturer requires; make the refrigerant and hydraulic connections through a buffer vessel into the heating circuit; upgrade the electrical supply and controls; then a phased cutover that keeps the existing boiler live as backup until the heat pump is proven, and a commissioning witnessed by the client against the BS EN 14825 design.
What this install includes
- Fastest, lowest-disruption install: no ground works, plant pre-assembled and craned to a compound or plant deck
- The live boiler cutover is usually a matter of hours, planned around your operating calendar
- Cascaded modular units allow the install to be staged and the site kept heated throughout
- Delivery risk is mostly siting and acoustic: separation, airflow and a BS 4142 assessment settled before order
Typical air-source heat pump installation
- Heat output
- 40-500 kW thermal
- Heat-pump plant
- single unit to cascaded banks of 4-12 modular units
- Plant / array area
- plant area 20-200 (external louvred compound or roof plant deck)
Cost, funding and how it is paid for
Installed cost depends on capacity, the state of the heating circuit, the electrical supply and the siting, so a air-source heat pump installation is priced from a heat-loss survey rather than a headline figure. As special-rate integral-feature plant it attracts the Annual Investment Allowance — 100% relief on the first £1m of qualifying spend. The 0% VAT relief covers only residential or relevant-charitable buildings, so general commercial premises do not qualify. See the cost guide, capital allowances and grants and funding.
Siting, acoustic and compliance
The dominant delivery risks are acoustic and siting. The planning route for external plant depends on the site, so confirm it with the local planning authority first; a BS 4142 acoustic assessment is commonly required to show the external plant stays within noise limits, and it is produced before the units are ordered. Defrost drainage, airflow clearances and screening are designed in. Refrigerant work requires engineers certified under the F-Gas Regulation.
MCS certification (or recognised commercial equivalent) for systems up to 45 kWth to access grant routes; above 45 kWth designs follow CIBSE and BSRIA standards with BS EN 14511/14825 rated performance. Permitted-development siting and noise limits apply, and a BS 4142 acoustic assessment is commonly required to demonstrate impact on neighbours. F-Gas-regulated refrigerant handling throughout. External plant needs designed-in airflow and defrost drainage, and the DNO supply capacity for the added electrical load is confirmed at survey.
Electrical supply and commissioning
A air-source heat pump installation adds electrical load, so the incoming supply capacity is confirmed at survey and any DNO supply upgrade started at feasibility — it is often the longest-lead item. Every install ends with a documented, commissioning witnessed by the client against the BS EN 14825 design. See also whether a commercial heat pump is worth it.
Related reading: the overview of commercial heat pump installation, the commercial heat pump cost guide, heat pump capital allowances, the heat pump cost calculator uk and how long does heat pump installation take.
For sizing, SCOP and siting detail, read the commercial air source heat pump guide.
Air-Source Heat Pump Installation: at a glance
| Attribute | Typical for this install |
|---|---|
| Heat output | 40-500 kW thermal |
| Plant / siting | plant area 20-200 (external louvred compound or roof plant deck) |
| Performance standard | BS EN 14825 (SCOP), commissioning witnessed by the client |
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Replies by email
- 1. Desk feasibility from the building details and consumption data you send, no obligation.
- 2. A plain assessment of the flow temperature and supply questions.
- 3. Next steps laid out plainly, with no obligation.
Common questions
How long does a commercial heat pump installation take?
An air-source retrofit is typically 4-12 weeks on site once design and any DNO supply work are agreed, and the live boiler cutover is usually a matter of hours. Ground-source and water-source take longer because of drilling, ground works and permits, often several months. Industrial, process and heat-network schemes run to 12 months or more including design, planning and grid works. The DNO supply upgrade, where one is needed, is frequently the longest-lead item, which is why it is started at feasibility rather than install week.
Does the building have to shut down or lose heat during the install?
No. The changeover is best planned around the building's operating calendar, typically spring or autumn, and for a hybrid or phased design the existing boiler can stay live as backup right through commissioning, so the building is not left without heat. Air-source plant is largely pre-assembled, so the live cutover is a matter of hours. Every tie-in is method-statemented and agreed with the site before works begin.
Do all the radiators and pipework have to be replaced?
Often not. Surveying the emitters before anything is designed shows what is needed. Many commercial systems run a heat pump at 50-55 C with selective emitter upgrades rather than a full strip-out. Where high flow temperatures are genuinely needed, a high-temperature heat pump (70 C+) or a hybrid design with a peaking boiler avoids re-emittering the whole building while still cutting carbon 70-90%.
How do you size a commercial heat pump?
From a heat-loss survey and at least twelve months of gas or oil consumption, never from floor area. Sizing sets the peak heat load and the flow temperature the emitters allow, because a lower flow temperature lifts the SCOP. Typical commercial air-source systems land between 40 and 500 kW thermal; ground and water-source 50 kW-1 MW+; industrial and heat-network schemes larger again. Specifying to BS EN 14825 makes quoted performance comparable across suppliers.
Will the electricity supply cope with the added load?
That is checked at survey, before anything is ordered. Large heat pumps add meaningful electrical load, so the available incoming supply capacity should be confirmed, and where a DNO supply upgrade is needed it is started at feasibility because it is often the longest-lead item. On constrained sites, phasing, hybrid designs or demand management can keep the project within capacity.