Commercial Heat Pumps: A UK Guide to Sizing, Costs and Grants
A commercial heat pump moves heat from outside air, the ground or waste heat into your building, using electricity to do it. One system can heat, cool and often supply hot water. For a UK business, the real questions are how big the system must be, what the whole project costs once emitters and electrics are counted, which grants apply, and whether your power supply can cope. This guide answers each, with the checks we would run before you sign anything.
TL;DR
Commercial heat pumps typically deliver two to eight times more heat per unit of electricity than gas or electric resistance heating, because they move heat rather than burn fuel.
Systems above 45 kW thermal are classed as large installations and need proper design, hot water integration and careful commissioning.
The Boiler Upgrade Scheme can fund smaller systems in England and Wales, but capacity is capped at 45 kWth for most applications.
The outdoor unit is only part of the bill. Emitters, electrics and controls often decide the final cost.
If you are also adding EV chargers, plan the electrical capacity for both at once.
Table of Contents
What a commercial heat pump actually does
A heat pump does not generate heat from fuel. It moves thermal energy from a cooler place to a warmer one, the opposite of how heat would naturally flow. In heating mode it pulls heat from outdoor air, the ground or water. In cooling mode it can run in reverse.
That is why efficiency is quoted as a coefficient of performance (COP). A COP of 3 means three units of heat for each unit of electricity. Manufacturers’ best-case figures reach a COP of 8, but real buildings rarely sit at the top of that range. Flow temperature, load profile and controls all pull the number down or up.
For a business this matters in three ways:
Running costs depend on your electricity tariff relative to gas, and on the real-world COP your site achieves.
Carbon falls as the grid decarbonises, with no on-site combustion.
Flexibility comes from combined heating and cooling, useful for offices, hotels, schools and leisure sites.
The main types of commercial heat pump system
Most UK commercial projects fall into one of four types.
Type | How it works | Typical fit |
Air source, air-to-water | Draws heat from outdoor air into a wet heating circuit and hot water cylinder | Offices, schools, retail, light industrial |
Air source, air-to-air | Transfers heat between outdoor air and indoor units using refrigerant | Open-plan spaces, shops, small offices |
Ground source | Uses buried pipework or boreholes for a stable heat source | Larger sites with land or piling, long ownership horizons |
Heat recovery or water source | Reuses rejected heat from process equipment, server rooms or other loads | Sites with constant waste heat |
Air source is the most common because it needs no ground works. Ground source costs more upfront but benefits from steadier source temperatures. As an illustration of scale, one LEED Platinum and BREEAM Outstanding office uses two 300 kW ground-source heat pumps for all its heating and most of its cooling, with pipework looped around structural piles.
Why heat recovery deserves a look
Many commercial buildings miss a simple gain: using heat they are already rejecting. The same CIBSE case study notes that recycling heat from sources such as server rooms or process equipment can cut energy demand sharply compared with conventional layouts. If your site has a cold store, data room, kitchen extraction or manufacturing process, ask any designer how that heat could feed other zones.
Sizing: when a system becomes “large”
In the UK, heat pump installations above 45 kW thermal output are treated as large systems. CIBSE’s guidance for these buildings highlights design points that smaller jobs can skip:
matching the load across the whole building, not zone by zone
integrating domestic hot water, which often has a very different temperature and timing profile from space heating
handling any process heat requirements
planning controls and monitoring from the start
A practical sizing sequence looks like this:
Measure the load. Use half-hourly gas and electricity data, not the size of the existing boiler. Old boilers are often oversized.
Reduce demand first. Insulation, glazing, air tightness and controls cut the capacity you must buy.
Check emitters. Radiators or fan coils sized for 70 °C flow will struggle at 45 to 55 °C. Some may need replacing or supplementing.
Decide on hot water. Separate cylinders, a high-temperature unit or point-of-use heaters each change the design.
Confirm the electrical supply. Heat pumps add a significant electrical load, especially at the coldest times.
What does a commercial heat pump cost?
There is no single price, and we will not pretend otherwise. Quotes vary because the work inside the building matters as much as the unit outside. Government evidence cited by one UK installer puts air source capital cost at roughly £1,500 per kW installed, against about £240 per kW for gas boiler plant. Treat that as a rough planning benchmark rather than a quote. Your actual figure depends on:
the size and type of system
emitter replacement or upgrades
hot water arrangements
electrical work, including any supply reinforcement
controls, metering and monitoring
access, plant space, scaffolding or crane lifts
When comparing quotes, compare like with like. Ask each bidder for the design flow temperature, the expected seasonal performance, what is excluded, and who is responsible if performance falls short. The Carbon Trust advises outcomes-based procurement: focus on comfort, efficiency and running costs for the whole system, and ask installers for evidence of past performance rather than relying only on accreditations such as MCS. That guide is written for social housing, but the principle carries over to commercial sites.
Grants and funding for UK businesses
The main scheme is the Boiler Upgrade Scheme (BUS). It supports heat pumps in homes and in small and medium non-domestic buildings in England and Wales. Key points from the official grant listing:
Grants of up to £7,500 are available as an upfront capital contribution.
The maximum installation capacity is 45 kWth, which the government says covers the vast majority of eligible properties.
Shared ground loop systems must not exceed 300 kWth overall.
The property must have a valid energy performance certificate.
The Boiler Upgrade Scheme (Amendment) Regulations 2026 continue the scheme, and the explanatory material says installers must deduct the grant from the upfront installation cost. Funding is committed at £2.7 billion through 2030, with £400 million in 2026/27. Always check the current rules on GOV.UK before you commit, because scheme terms change.
Three cautions:
BUS covers England and Wales only. Scotland and Northern Ireland have separate support.
It is aimed at small and medium buildings. A site needing well over 45 kW is unlikely to fit.
Apply through your installer and do not start work until you understand the voucher process.
Why commissioning decides whether it works
The most common failure point on larger systems is not the equipment. It is commissioning and what happens afterwards. CIBSE’s guidance on large installations stresses feedback loops, where operational data refines the control strategy over the life of the equipment.
The Carbon Trust makes a related point: heat pumps do not behave like boilers, and real-world efficiency depends on a chain of decisions from design through installation, commissioning and daily use. Two compliant systems can perform very differently.
Before handover, insist on:
a commissioning record with measured flow temperatures and flow rates
heat and electricity metering so you can calculate actual performance
a seasonal review, with controls adjusted against real data
clear training for whoever runs the building
Getting the board to approve it
Heat pumps often stall internally because they look technical or optional. The Carbon Trust’s work on SME energy efficiency finance notes that internal approval is a common barrier, and that projects succeed when they are presented around energy cost savings, brand reputation and future-proofing against decarbonisation requirements.
A business case that works usually includes:
today’s gas and electricity costs, and a range for future prices
the grant, if you qualify
the cost of doing nothing, including future boiler replacement
lifecycle thinking: CIBSE research on embodied carbon in building services suggests judging HVAC over a realistic horizon, such as a 12-year tenancy or a 60-year building life
Our perspective: plan heat and EV charging as one electrical project
We are an EV charging company, so we see the same constraint on almost every commercial site: electrical capacity. A heat pump adds a large new load. EV chargers add another. If they are specified by different contractors a year apart, the second project often discovers the first has used the headroom.
Our advice, based on how we approach commercial sites:
Survey once. Look at the incoming supply, the main distribution board and the likely future loads together.
Use load management. Smart charging can keep EV demand from colliding with heating peaks, which can avoid costly grid upgrades. We explain the principle in our guide to smart charging for fleets.
Look at on-site generation and storage. Solar PV and battery storage can offset some of the new electrical demand, and we help commercial customers assess them alongside charging.
Be honest about fit. Not every site suits every technology. A feasibility review should tell you what not to do as well as what to do.
We do not pretend to replace a specialist heating designer for a large plant room. What we can do is make sure your charging, energy and electrical planning does not fight your heating plans.
— Swift Charging
Planning heat pumps alongside EV charging
If your site is moving towards electric heating and electric vehicles at the same time, a joined-up assessment saves money. Our energy solutions for businesses cover solar PV, battery storage and heat pumps with EV charging in mind. For a first look at what your supply can handle, our commercial EV feasibility review is a free-to-ask starting point for your site assessment, and our workplace EV charging and fleet charging services can then be sized around the capacity left.
For depots, the same logic applies: charge at the depot first and manage demand, so heating and vehicles share a supply without an expensive upgrade.
A checklist before you request quotes
Gather 12 months of energy bills and, if possible, half-hourly data.
Check your EPC and any upcoming landlord or tenant obligations.
Identify the existing heating system, emitters and hot water arrangements.
Ask your network operator and electrician about spare supply capacity.
Decide whether you want heating only, or heating and cooling.
Check BUS eligibility if the system is 45 kW or smaller and the site is in England or Wales.
Request quotes that state flow temperature, exclusions, commissioning and aftercare.
Ask for performance evidence from comparable sites.
Common mistakes to avoid
Sizing from the old boiler. It is often oversized and wastes capital.
Ignoring hot water. It can be a large share of demand in hotels, leisure sites and schools with showers.
Skipping metering. Without data you cannot tune or prove performance.
Treating the grant as the plan. The grant helps, but the project must work without relying on it to hide a poor design.
Forgetting the power supply. This is the one that surprises most businesses.
FAQ
Do commercial air source heat pumps work in winter?
Yes. An air source heat pump can still extract heat from cold outdoor air, although efficiency falls as temperatures drop. Good design, correct sizing and sensible flow temperatures matter more than the weather. Ask your designer for expected performance at your design winter temperature.
Can my business get a grant for a heat pump?
Possibly. The Boiler Upgrade Scheme supports small and medium non-domestic buildings in England and Wales, with a capacity limit of 45 kWth and a requirement for a valid EPC. Check the current rules on GOV.UK and ask your installer to confirm eligibility before you accept a quote.
What counts as a large commercial heat pump?
In UK guidance, a system with thermal output above 45 kW is treated as large. These need building-wide load matching, hot water integration and careful commissioning. They also fall outside the usual BUS capacity limit.
Can I install a heat pump and EV chargers at the same site?
Yes, but check the electrical supply first. Both add significant load, and load management for the chargers can help avoid a costly supply upgrade. A joint assessment is usually cheaper than two separate ones.
Sources
AM17 Heat pump installations for large non-domestic buildings, CIBSE
The Boiler Upgrade Scheme (England and Wales) (Amendment) Regulations 2026, legislation.gov.uk
CIBSE case study: the first LEED Platinum and BREEAM Outstanding building
Improving heat pump outcomes in social housing, The Carbon Trust
Commercial heat pump installation costs, UK pricing for businesses and landlords
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