Commercial Air Conditioning: Replacement and Retrofit
September 8, 2025
Commercial air conditioning cost in the UK is not one number. It depends on the building, the hours of use and the level of control you need. The type of system matters too. Splits, VRF and evaporative cooling serve different spaces and budgets. Installation also affects price. Power supply, safe access and working hours can raise or lower the total.
We set budgets with a clear method. First we survey and model the heat gains. Then we design a solution that balances comfort, efficiency and cost over its life. Our installation plans account for electrical capacity and site logistics so there are no surprises. We also build in compliance from the start, including TM44 inspections and F-gas responsibilities where they apply. The goal is a precise, readable proposal that shows what you will spend and why.
What Drives Commercial Air Conditioning Cost in the UK?
Getting the budget right starts with the building. Two sites of the same size can need very different solutions. We look at how much heat the space generates, how the building holds that heat, and how the space is used across the day and year.
Fabric and glazing. Insulation levels, window area and orientation affect heat gains and losses.
Internal gains. People, servers, process equipment and lighting add to the load.
Air movement. Ventilation rates, air tightness and infiltration change the duty on the system.
Operating hours. Longer hours and seasonal peaks increase the running duty and influence the design.
We model these inputs before we talk kit. That gives a clear basis for sizing and prevents overspecifying equipment that will cost more and run less efficiently.
Cost is influenced as much by the route to install as it is by the equipment.
Power availability. Spare capacity at the board, new circuits, isolation points and containment.
Refrigerant and condensate routes. Length, height and penetrations through fire compartments or listed features.
Outdoor plant location. Roof or yard availability, screening, noise constraints and structural checks.
Access and lifting. Cranes or hoists, road closures and safe access to roofs.
Working conditions. Live environments, out-of-hours or phased delivery to maintain operations.
Finishes and making good. Ceiling types, fabric repairs and any required decoration.
For a step-by-step view of typical programmes and what to expect on site, see our commercial air con installation guide.
The system type is a major cost driver because it sets both the installation method and the running efficiency.
Split and multi-split. Suited to small rooms and cellular layouts. Quick to install with minimal ceiling work.
VRF or VRV. Flexible zoning for larger floorplates and mixed uses. Higher indoor unit count and longer pipe runs increase labour and materials but can deliver excellent control.
Ducted solutions. Useful where discreet appearance and supply air distribution are priorities. Expect added cost for ductwork, grilles, acoustic treatment and coordination.
Close control or specialist. Required where tight temperature or humidity bands apply.
Evaporative cooling. A strong option for large, well-ventilated spaces such as warehouses and production areas. Capital and running costs can be lower when fresh-air volumes are high and setpoints are moderate.
If you want a quick primer on the options, our overview of commercial air conditioning systems sets out the main categories and where each fits.
Good controls protect comfort and cost. Zone control, occupancy sensors, setback schedules and remote monitoring avoid waste. Where needed, we integrate with a site BMS or provide a simple central controller. Clear sequences at handover help your team operate the system as intended.
Commissioning quality and documentation shape total cost of ownership. We provide test results, as-built drawings and user guidance, and we schedule the first service visit so the system stays within warranty. Ongoing care keeps energy use stable and prevents small issues from becoming costly faults. Our planned maintenance service outlines the tasks and intervals we recommend.
Typical Installed Costs by System Type
No two projects are the same, but there are reliable bands that help set expectations for commercial air conditioning cost UK in 2025. Final figures still depend on survey findings, access, electrical capacity and programme.
| System type | Typical installed range | Where it fits best |
|---|---|---|
| Single split | £2,500 to £6,000 per room | Small rooms, cellular offices, retrofit spaces |
| Multi-split | £5,000 to £10,000+ for 3-5 rooms | Small suites needing individual control |
| Ducted | £7,000 to £20,000 for a small suite | Open-plan offices, retail floors needing discreet supply |
| VRF or VRV | £10,000 to £75,000+ project bands | Medium to large offices, hotels, multi-tenant floors |
| Evaporative cooling | £900–£1,600 per kW equivalent cooling effect Often 40 to 60% lower capex than like-for-like refrigeration in large spaces | Large volume spaces, warehouses, production areas |
Note that ranges are indicative and depend on survey, access, electrical works, ceiling and fabric making good, and any out-of-hours working. For a deeper look, see our guide to commercial air conditioning services and our explainer on ducted air conditioning.
Cost Factors You Might Miss
Early budgets often focus on kit and labour only. The following items can add meaningful cost and should be considered from the outset.
Electrical works: dedicated circuits, isolators, containment and any board upgrades.
Refrigerant and condensate routes: long runs, height changes and penetrations through fire compartments or listed features.
Access and lifting: cranes or hoists for roof plant, road closures, safe roof access.
Working conditions: live environments, phased delivery or night and weekend working.
Finishes and making good: ceilings, grilles, acoustic treatment, decoration.
Compliance deliverables: commissioning records, user training and as-built drawings.
If you want a budget that reflects your building and programme, we will survey, model loads and issue a clear, itemised proposal. For whole-life cost control, factor in planned servicing from the start.
Estimating Running Costs in 2025
Running cost is a function of demand and efficiency. In practice, it comes down to how much cooling the space needs across the year, how efficiently the system turns electricity into cooling, and how the controls avoid waste.
Inputs
Start with a simple checklist before any maths.
Cooling demand. Space type, occupancy, equipment heat gains and solar gain set the baseline duty.
Hours of use. The more hours at load, the larger the annual consumption.
Seasonal efficiency. Look at SEER or SCOP rather than a single-point EER or COP. These seasonal ratings give a more realistic view across varied UK weather.
Setpoints and control. Small changes in setpoint, proper scheduling and setback can trim hours at full load.
Tariff. Use your current p/kWh, not a generic figure. For context, the manufacturing average in Q1 2025 was about 18.5 p/kWh, down year on year. Actual contracts vary, so we always model with the live tariff.
Get these inputs right and you will have a reliable view of consumption and the quickest ways to reduce it.
Estimating Consumption
Using a structured approach can help you to come up with a good idea of how much your energy costs are likely to be.
Size the duty sensibly. Use a load model rather than a rule of thumb so diversity and part-load are captured.
Apply a seasonal efficiency. For packaged direct-expansion systems, SEER values are usually a better guide than “nameplate” EER. VRF systems typically operate much of the time at part-load where they are more efficient than at full load.
Map to hours. Multiply the likely hours of operation in each season by a realistic part-load factor.
Check controls. Add the savings impact of schedules, occupancy sensors and free-cooling or fresh-air strategies where relevant.
Use the live tariff. Prices move. Even within a single year, contract rates can differ widely by sector and consumption band. Keep the model current with your latest bill or contract. For market context, the government’s June 2025 release shows the manufacturing sector average at 18.5 p/kWh in Q1 2025.
Factors that Push Bills Up or Down
Setpoint creep. Each degree lower on cooling raises energy use. Keeping realistic targets stabilises consumption.
Poor airflow. Blocked filters and dirty coils increase fan and compressor work. Routine tasks in our planned maintenance service prevent this performance drift.
Unnecessary simultaneous heating and cooling. Good zoning and clear sequences avoid counteracting operation.
Run-on outside occupancy. Tighten schedules and use occupancy or CO₂ signals where appropriate.
Tariff structure. Demand charges and time-of-use rates can outweigh small efficiency differences. Align control strategies with your tariff.
Evidence-Based Budgeting
At Inergy Group, we keep the process simple. Share recent energy bills and any metered data, plus your operating hours and comfort targets. We then model seasonal demand, apply manufacturer performance data at part-load, and test control strategies that fit your site. The output is a clear annual kWh estimate paired with sensible sensitivities. That gives a reliable range for decision-making and a benchmark to track after installation.
Regulation affects both the up-front scope and the ongoing budget. We design and price with these duties in mind so the proposal is compliant on day one and practical to maintain.
TM44 Air Conditioning Inspections
If your combined effective output is over 12 kW, an accredited inspection is required at least every five years. Trading Standards can request the report and issue fixed penalties if it is missing or not provided promptly. We confirm whether you are in scope at survey and include TM44 status in the handover pack.
F-Gas Obligations in Great Britain
Operators must prevent leaks, check equipment at set intervals, keep records and use qualified people. Leak-check frequency is based on the carbon-dioxide equivalent of the charge, with additional requirements at higher thresholds. Records are kept for systems above a defined CO₂e threshold. Northern Ireland follows the EU regime; Great Britain retains its own.
What to Budget For
TM44 inspections every five years where total capacity exceeds 12 kW.
Leak checks at the correct frequency and automatic detection where required.
Refrigerant and maintenance records kept for the required period.
Only certified engineers working on systems that contain F-gas.
Our maintenance plans build in the required checks, record keeping and renewal reminders so compliance stays on track.
Planned servicing protects comfort, keeps energy use stable and reduces the risk of unplanned downtime. We design maintenance around the equipment type, hours of use and criticality of the space.
Service Intervals and Scope
Intervals. Light-use splits often need one planned visit per year. Most commercial sites benefit from two. Critical spaces may need more frequent checks.
Core tasks. Clean or replace filters, clear condensate lines, clean indoor and outdoor coils, check fans and bearings, verify controls and sensors, tighten terminations, test safeties, review fault logs.
Refrigerant management. Visual checks for oil staining, verify operating pressures and temperatures against expected values, complete leak checks where regulation requires, update asset records.
Evaporative cooling. Inspect pads, pumps and water distribution, confirm bleed rates, check make-up water quality and water hygiene controls, verify airflow paths and purge strategy.
Keeping Performance High
Minor faults waste energy. Clean heat-exchange surfaces reduce compressor effort and keep pressures in line with design. Balanced airflow lets coils do their job; blocked filters or obstructed grilles make fans work harder for less effect. Calibrated sensors prevent over-cooling and stop systems from hunting. Clear schedules, sensible night setback and occupancy control trim run hours without sacrificing comfort.
Predictive and Corrective Work
Inergy Group reviews alarms and operating trends to catch faults early. Common corrective items include float switches, condensate pumps, contactors, fan motors, PCBs and control sensors. We advise when a part should be replaced proactively to avoid disruption during peak periods.
Lifecycle Planning and Renewal
Expected service life. Well-maintained split and VRF equipment typically delivers a long life. Duty, environment and maintenance quality make the difference.
When to replace. We compare the cost of repair with the efficiency gains of modern equipment and the likely remaining life of the asset. If repair cost is material and the unit is near end of life, a planned replacement can lower whole-life cost.
Budgeting. Allow for routine filters and media, periodic deep cleans, occasional component replacement and statutory checks alongside planned visits.
What Inergy Group Delivers
Our maintenance plans include a clear schedule of visits, task lists for each equipment type, asset registers and simple reporting. You get evidence of the work, recommendations ranked by urgency and a rolling view of parts and renewal priorities. This keeps performance steady and costs predictable.
Project Scope and Pricing
At Inergy Group, we price from evidence. First we survey the site, review plans and routes, check electrical capacity and note any landlord or heritage constraints. We model the cooling load to size the duty and set diversity. From there we explain the viable system options, how zoning and controls affect comfort and running cost, and what each choice means for installation time and access.
Most installs happen in live environments, so we plan phasing to keep operations running. Noisy or disruptive tasks are scheduled out of hours where required. We coordinate lifting, roof access and containment so routes are safe and tidy. Documentation and compliance are built in. Commissioning plans, test sheets and as-built drawings are included as standard. Where fluorinated refrigerants are present, we outline operator duties and provide an asset register template at handover.
Our pricing is itemised. You see equipment, materials and labour, plus allowances for electrical works, making good and any lifts. Provisional sums and exclusions are called out clearly. If a value-engineering route is sensible, we show the impact on whole-life cost so you can choose with confidence. To help us quote quickly, send floor plans, photos of plant areas and access routes, board schedules or spare-capacity notes, operating hours and comfort targets. When you are ready to begin, contact our team and we will propose survey dates.
Frequently Asked Questions
How much does a small office install cost?
For a simple single split serving one room, a realistic band is £2,500 to £6,000 ex VAT once survey, access and electrical works are considered. Larger or more complex spaces trend higher.
What size system do I need?
Capacity follows the load model. We measure fabric, glazing, solar gain, people and equipment heat. Right-sizing avoids overspend on capital and keeps seasonal efficiency high.
How long does installation take?
A straightforward single split can be completed quickly once access is confirmed. Multi-split, ducted and VRF projects take longer due to routes, ceilings, controls and commissioning. We plan phasing so operations continue.
What affects commercial air conditioning cost UK the most?
Load, system choice and access. Long pipe runs, difficult routes, night working and lifting can add meaningful cost. Good design and planning reduce these pressures early.
What are typical running costs per hour?
It depends on duty, seasonal efficiency, setpoint and tariff. We estimate using your hours and current p/kWh, then stress-test the result with sensible ranges so you can budget with confidence.
Do I need a TM44 inspection?
If the combined effective rated output is over 12 kW, yes. The interval is at least every five years. We confirm scope at survey and include status in the handover file.
Who looks after leak checks and records?
Where systems contain fluorinated refrigerants, leak checks, record keeping and qualified personnel are required. We set this out clearly and provide an asset register template at handover.
Is there a quick way to compare options before a survey?
Yes. Our expert air conditioning solutions article outlines typical scenarios, timeframes and budget signals so you can start shaping the brief. It is a useful primer before we visit.
Next Steps
Share a few basics with Inergy Group and we will move quickly. Send floor plans, photos of plant areas and access routes, electrical board details, operating hours and any landlord or heritage constraints. If you have recent energy bills, include a month that reflects typical use.
We will propose survey dates, confirm constraints and issue an itemised budget range. The proposal sets out system options with clear trade-offs, a draft programme, allowances for electrical works and making good, and the compliance pathway where fluorinated refrigerants apply. You will also see a simple maintenance plan with visit frequency, tasks and reporting so whole-life cost is transparent from the start.
Ready to begin? Contact Inergy Group and we will respond with available dates and the information we need to quote accurately.
