Commercial HVAC: guides & comparisons
In-depth, no-nonsense guides and comparisons on commercial HVAC — VRF vs chillers, heat pumps vs gas, F-gas, MEES, running costs and PPM. Dated and honest, updated for 2026.
2-pipe or 4-pipe fan coil systems?
2-pipe against 4-pipe fan coil systems: changeover, spring and autumn comfort, pipework, controls and energy, with a worked office example.
Read guide → Cooling guideAbsorption chillers: when waste heat can drive cooling
How a lithium bromide absorption chiller works, the heat it needs, its low COP, and why it needs bigger heat rejection than an electric chiller.
Read guide → Repairs and faultsAC compressor replacement: what it costs and when to replace the system instead
Why compressors fail, what a replacement quote is built from, how the R22 ban affects repairs, and a five-point repair-or-replace test.
Read guide → Maintenance guideAHU maintenance checklist: tasks and frequencies
Component-by-component AHU checks, the few intervals that are published, and how filter and fan monitoring can extend the rest safely.
Read guide → Cooling guideAir conditioning condensate pumps and drains in commercial buildings
Gravity falls, built-in and external pumps, alarm wiring and discharge permission for air conditioning condensate, from maker manuals and official sources.
Read guide → Controls guideAir conditioning controls for offices: how to stop wasted cooling
Schedules, separate setpoints, lockouts, resetting overrides and occupancy modes: the office controls that cut wasted cooling, with a worked kWh example.
Read guide → Buyer's guideElectrical supply for commercial air conditioning: single or three phase?
Which units take single-phase or three-phase power, what the circuit needs, what the electrician certifies and when Part P reaches commercial premises.
Read guide → Tax and fundingIs there a grant for air conditioning for businesses?
What the official scheme pages say about grants, tax relief and loans for business air conditioning, checked 22 October 2026.
Read guide → Comparison guideAir conditioning hire or buy: what makes sense for a business?
Hire or buy cooling? A break-even method using ratios, what GOV.UK says on allowances, who carries F-gas duties, and what to ask first.
Read guide → Repairs and faultsWhy is commercial air conditioning leaking water?
Common causes of water leaking from cassettes, wall units and ducted units, the safe checks for a site team, and when an F-gas engineer is needed.
Read guide → Compliance guideCan air conditioning spread legionella?
Which air conditioning plant is a legionella risk, which is not, and what L8 and HSG274 require of the duty holder.
Read guide → Compliance guideAir conditioning in listed buildings and conservation areas
Listed building consent, conservation areas and Article 4 directions explained for commercial air conditioning, with design approaches and devolved differences.
Read guide → Compliance guideCommercial air conditioning noise: limits, assessments and complaints
How councils judge external air conditioning noise: BS 4142 assessments, background-based limits, noise controls and what happens when someone complains.
Read guide → Compliance guideDo you need planning permission for commercial air conditioning?
No permitted development class covers commercial air conditioning in England. What the order says, how councils judge noise and looks, and what to check first.
Read guide → Repairs and faultsRefrigerant leaks in commercial air conditioning: signs, costs and legal duties
Signs of a refrigerant leak, why topping up is not a repair, how leaks are found, and the leak-check intervals and records the law requires.
Read guide → Compliance guideCommercial air conditioning regulations: the UK checklist
One checklist of every legal duty on commercial air conditioning, from F-gas and 12 kW inspections to Building Regulations, planning, noise and waste.
Read guide → Cooling guideRetrofitting air conditioning into an existing office
The order of decisions when an existing office gets air conditioning for the first time: load, routes, planning, lease, asbestos, occupied working and Part L.
Read guide → Maintenance guideWhy does commercial air conditioning smell?
Match a damp, burning, drain or exhaust smell to its likely cause, and see what staff can check and what needs a specialist.
Read guide → Heating guideDo air curtains work for shop doors?
How air curtains work at open doors, the ways they fail, ambient versus heated types, and a kWh worked example to test payback.
Read guide → Regional dataAir quality management areas: what they mean for ventilation intakes and filters
What an AQMA is, how to check a site, a snapshot of major UK cities from council pages, and what it means for intake siting, filter grades and monitoring.
Read guide → Compliance guideAsbestos in old HVAC plant and ductwork: what to check first
Where asbestos turns up in older HVAC plant, who holds the duty to manage, which survey comes before replacement and the order of work.
Read guide → Cooling guideATEX air conditioning for hazardous areas
DSEAR zones, equipment categories and markings, the options for cooling hazardous areas, GB and Northern Ireland differences, and an ATEX brief.
Read guide → Cooling guideWhat is the ideal beer cellar temperature?
The cellar temperature Cask Marque works to, how heat reaches cask beer, what a cooler rating means and what to check when the cellar runs warm.
Read guide → Controls guideBuilding management systems for HVAC: what they do and what drives the cost
What a BMS does for HVAC, its parts, BACnet and Modbus, what drives the cost, and how to maintain and secure it.
Read guide → Comparison guideCassette, ducted or wall-mounted air conditioning?
How wall-mounted, cassette, ducted and floor-standing indoor units differ on air distribution, noise figures, ceiling void and servicing access.
Read guide → Comparison guideChilled beams or fan coil units for an office?
Active and passive chilled beams against fan coil units: dew point, capacity, noise, upkeep, ceiling space and energy, with sourced figures.
Read guide → Maintenance guideChiller maintenance and lifespan: what to budget
What chiller maintenance covers, F-gas leak check intervals, pressure system duties, service life evidence and what a budget should include.
Read guide → Refrigerant guideChiller refrigerants after R134a: R1234ze, R513A and others
R134a chillers are not banned. Compare R1234ze, R513A, R515B, R32, R290 and natural refrigerants on GWP, class, plant room and retrofit.
Read guide → Maintenance guideCommercial air conditioning cleaning: what to clean and how often
Filters, coils, trays and fans: what to clean, how often, what dirt does to capacity, and how a clean differs from a service.
Read guide → Buyer's guideHow long does a commercial air conditioning installation take?
The stages of a commercial air conditioning installation, what decides each, and the planning, network operator and commissioning clocks that are set in law.
Read guide → Repairs and faultsCommercial air conditioning not cooling? Ten causes to check first
Ten causes of weak cooling in multi-zone, VRF and server room systems, in checking order, with what staff can check and what needs an engineer.
Read guide → Heating guideWhat does a commercial boiler replacement cost?
What goes into the cost of replacing a commercial boiler, which rules set the specification, and running costs worked at DESNZ fuel prices.
Read guide → Ventilation guideCommercial dehumidification: when a building needs it and what it costs
When a commercial building needs dehumidification, how condensing and desiccant plant compare, how to size from moisture load and what it costs to run.
Read guide → Ventilation guideCommercial extractor fans: types, sizing and costs
Extractor fan types, how to size one from airflow and pressure, the efficiency rules, and the cost drivers, with worked examples and no prices.
Read guide → Ventilation guideCommercial MVHR: does heat recovery pay back?
When commercial heat recovery pays back: the sum, ecodesign minimums, and illustrative office and school examples at DESNZ non-domestic prices.
Read guide → Cooling guideCommercial portable air conditioning: when it works and when it doesn't
Is portable air conditioning illegal in the UK? The rules that apply, the heat, water and noise limits, and when a fixed system is the better answer.
Read guide → Refrigerant guideCommercial HVAC refrigerants: GWP table and guide
GWP on the Great Britain legal basis, A1, A2L and A3 safety classes, typical uses and the charge that triggers F-gas leak checks, in one table.
Read guide → Heating guideCommercial underfloor heating: costs and where it works
Where wet and electric underfloor heating suit commercial buildings, the floor output limit, finishes, cost drivers, and a kWh running comparison.
Read guide → Regional dataCooling and heating degree days by UK region
What degree days measure, where official UK figures sit (Met Office, DESNZ, CIBSE), and an illustrative regional comparison from station averages.
Read guide → Cooling guideCooling towers, dry coolers and adiabatic coolers compared
How cooling towers, dry coolers and adiabatic coolers differ on water use, hot-day capacity, plume and Legionella duties, with the trade-offs for UK summers.
Read guide → Comparison guideCRAC or CRAH units for server rooms and data centres?
CRAC and CRAH units compared: DX against chilled water, free cooling, containment, redundancy, maintenance and how the units are rated.
Read guide → Cooling guideData centre cooling methods compared
Air, liquid and free cooling for data rooms compared: how rack density drives the choice, what liquid cooling needs and how PUE is reported.
Read guide → Ventilation guideDecentralised MVHR: single-room units for offices and schools
Single-room MVHR for classrooms and offices: how many units a room needs, what two published specifications show, noise, upkeep, and when central wins.
Read guide → Ventilation guideDemand-controlled ventilation: how CO2 sensors cut ventilation energy
How CO2 and occupancy sensors vary fresh air, where demand-controlled ventilation saves most, sensor placement, and a worked saving at DESNZ prices.
Read guide → Heating guideDo destratification fans cut heating costs?
What decides whether destratification fans save heat, with a worked estimate at DESNZ fuel prices that includes the fans' own electricity.
Read guide → Ventilation guideDW/144 explained: ductwork standards and air leakage testing
What DW/144 covers, how leakage classes and tests work, and what Approved Document L expects of ductwork on new commercial systems.
Read guide → Ventilation guideEC fans: retrofit savings for AHUs and fan coils
EC against belt-driven fans, the ecodesign rules for replacement fans, an illustrative kWh example, retrofit steps and the risks to check.
Read guide → Buyer's guideIs there enough electrical capacity for your new HVAC plant?
Compare agreed kVA with measured demand and the new plant's load, then see the options, steps and published timescales if headroom runs out.
Read guide → Cooling guideHow to choose energy-efficient commercial air conditioning
SEER, SCOP and seasonal ratings explained: the legal floor, the label bands up to 12 kW, what to ask on VRF and chillers, and a kWh example.
Read guide → Comparison guideEvaporative cooling or air conditioning for a business?
Evaporative cooling cannot beat the wet-bulb temperature and adds humidity. A worked comparison with air conditioning, plus water, legionella and TM44 points.
Read guide → Buyer's guideHow to check a contractor's F-gas certificate
The difference between a company F-gas certificate and an engineer's qualification, and how to check both before work starts.
Read guide → Cooling guideFan coil units: types, capacities and where they fit
Fan coil unit types, capacity ranges, FCU versus AHU, where they beat VRF, cost drivers, maintenance and service life, with sources.
Read guide → Regional dataFree cooling chillers: how many hours each UK region offers
Modelled hours at or below 2, 5, 10 and 15 degrees by UK region, what they mean for free cooling chillers, and an illustrative kWh example.
Read guide → Compliance guideThe Future Buildings Standard: what Part L 2026 changes for HVAC
Dates, the transitional rule and the reworded Part L requirement for HVAC plant in England, with Wales, Scotland and Northern Ireland noted.
Read guide → Compliance guideGas interlock systems for commercial kitchens
What a kitchen gas interlock does, who is responsible, how fan failure is detected, whether older kitchens need one and how it is tested.
Read guide → Refrigerant guideGB F-gas rules in 2026-27: what changed and what didn't
A dated check of Great Britain's F-gas rules: Defra's consultation, the 2027 step, 2026 guidance updates and what stays the same.
Read guide → Comparison guideHeat recovery or heat pump VRF?
Is VRF a heat pump? What heat recovery adds, how 2-pipe and 3-pipe designs differ, and which buildings gain from moving heat between zones.
Read guide → Regional dataWhere are the hottest places in the UK, and what does that mean for cooling?
Met Office July averages and records by region, how heatwave thresholds differ by county, and what the data means for building cooling.
Read guide → Cooling guideHow does commercial air conditioning work?
The four-stage refrigerant cycle behind every commercial cooling system, what each part looks like on site and why refrigerant is regulated.
Read guide → Cooling guideHow long does commercial air conditioning last?
No single official lifespan applies. What CIBSE publications say for VRF and chillers, what shortens or extends life, and how to plan replacement early.
Read guide → Buyer's guideHow to choose a commercial HVAC contractor
Twelve checks a buyer can apply to any commercial HVAC contractor, with the rules, registers and standards behind each one.
Read guide → Buyer's guideHow to compare commercial HVAC quotes
A twelve-line checklist for putting commercial HVAC bids on a like-for-like basis, with the rules and standards each line draws on.
Read guide → Buyer's guideHVAC commissioning: what a proper handover includes
What commissioning should prove, the standards behind each test, and a handover checklist of the records a client can ask for before final payment.
Read guide → Ventilation guideHVAC dampers explained: volume, fire and smoke dampers
The damper types in commercial ductwork, where fire dampers are called for, the testing duty under the Fire Safety Order and the records to keep.
Read guide → Ventilation guideHVAC filter grades explained: ISO 16890, G4 and F7
ISO 16890 classes against the old G4 and F7 grades, how to choose by building, what pressure drop costs in fan energy and when to change filters.
Read guide → Ventilation guideHumidifiers in HVAC: steam versus adiabatic
How electrode, resistive, gas-fired, spray, wetted-media and ultrasonic humidifiers differ on energy, water treatment, hygiene and legionella control.
Read guide → Maintenance guideHVAC maintenance contracts: 15 clauses to check before you sign
Fifteen questions to put to any HVAC maintenance bidder, from asset register and F-gas records to subcontracting, exit and handover.
Read guide → Maintenance guideHVAC PPM schedule: a task-frequency template
Which HVAC maintenance frequencies are set by law, which come from the manual or SFG20, and how to build the asset register and calendar.
Read guide → Cooling guideHVLS fans for warehouses: do they keep staff cool?
HVLS fans move air rather than cool it. What HSE says, where they stop helping, how sprinklers affect layout, and what a proposal should state.
Read guide → Ventilation guideHow to control humidity in an indoor pool hall
Published pool hall air and humidity conditions, how the set-point changes energy use, what covers do and how to find condensation risk.
Read guide → Heating guideDoes infrared heating work in offices and workshops?
Where electric infrared panels suit offices and workshops, what Part L expects, and running-cost sums against gas and heat pumps at DESNZ prices.
Read guide → Refrigerant guideIs air conditioning being banned in the UK?
No, air conditioning is not banned. A dated guide to which refrigerants, new products and servicing practices are restricted, and what owners must do.
Read guide → Cost guideIs air conditioning worth it for a UK business?
A decision framework: what the law says about workplace heat, where cooling pays, cheaper steps first, a kWh cost method and the tax treatment.
Read guide → Compliance guideThe London Plan cooling hierarchy: when London planners accept air conditioning
London Plan Policy SI 4 puts air conditioning last in a six-step cooling hierarchy. What a submission shows, how boroughs apply it, and the 2026 draft plan.
Read guide → Ventilation guideCan MVHR cool a building?
Why MVHR rarely replaces air conditioning: the bypass, the airflow cap on cooling capacity, worked office arithmetic, and the coil and heat pump options.
Read guide → Repairs and faultsNoisy air conditioning: what the sounds mean
Normal and abnormal air conditioning sounds from manufacturers' manuals: hissing, buzzing, rattling and gurgling, and who to call for each.
Read guide → Cost guideHow much does it cost to air condition an office? Three worked examples
Three office examples, a single room, an open-plan floor and a 50-person VRF floor, with running cost worked out and installed-cost drivers listed.
Read guide → Cooling guideProcess and glycol chillers for manufacturing and brewing
Why process chillers use glycol, how to size one from the process heat load, which ecodesign rules apply by outlet temperature, and the F-gas duties.
Read guide → Refrigerant guideR290 (propane) air conditioning in commercial buildings
What R290 propane means for commercial air conditioning: A3 class, charge limits, DSEAR, F-gas status and how it compares with R32.
Read guide → Ventilation guideSpiral, rectangular or flexible ductwork: which to use?
How rectangular, circular (spiral), flat oval and flexible ductwork compare on space, leakage, fan energy, fire and cost drivers.
Read guide → Comparison guideSplit, multi-split or VRF: which commercial air conditioning?
How single splits, multi-splits and VRF differ by zones, charge, leak-check band, controls and upkeep, plus a sourced rule of thumb for choosing.
Read guide → Cooling guideThrough-wall air conditioning units: when they suit a business
Through-wall air conditioning: how it works without an outdoor unit, where it suits, noise and efficiency trade-offs, wall-opening rules and F-gas position.
Read guide → Compliance guideTR19 Grease: kitchen extract cleaning frequencies, insurers and what drives the cost
TR19 Grease cleaning intervals, how grease thickness is read and reported, why insurers ask for it, and what a quote should state.
Read guide → Cooling guideTypes of chillers explained
Air-cooled or water-cooled, scroll, screw or centrifugal, heat pump, free cooling or absorption: how commercial chiller types differ and where each fits.
Read guide → Tax and fundingWhat VAT applies to commercial air conditioning?
Why commercial air conditioning is normally charged at 20% VAT, when the 0% rate can apply, and what HMRC says about recovery.
Read guide → Ventilation guideVAV systems explained: variable air volume for offices
How VAV terminal boxes, reheat and fan control work, why offices use them, how VAV compares with fan coils and VRF, and what goes wrong.
Read guide → Ventilation guideVentilation duct cleaning: what TR19 Air expects
How TR19 Air cleanliness is measured, how often BESA says to inspect, and what a verified duct clean should leave behind.
Read guide → Heating guideHow to heat a warehouse: warm air, radiant or destratification?
Warm air, radiant tubes or electric: what HSE says about warehouse temperature, the efficiency rules, and running costs worked at DESNZ's published fuel prices.
Read guide → HVAC basicsWhat is HVAC? A plain-English guide for UK buildings
What HVAC stands for, the UK term for it, and the five system families a commercial building uses, from splits and VRF to controls.
Read guide → Regional dataWill UK buildings need air conditioning? What the climate projections say
Met Office projections and 2026 observations by UK region, which buildings feel heat first, and the cooling hierarchy that puts passive measures first.
Read guide → Compliance guideWorkplace temperature law in the UK: what employers must do
What the Workplace Regulations require on temperature, what HSE says about 16C, 13C and heat, and the steps employers take in hot weather.
Read guide → energy efficiencyHow to Reduce Commercial Building Energy Use Through HVAC
Controls, heat recovery, free cooling and EC-fan retrofits — the HVAC measures that cut commercial building energy, ranked by where the savings live.
Read guide → fundingHow to Fund a Commercial HVAC Upgrade — the Real Routes
The Boiler Upgrade Scheme covers small heat pumps only. The real funding: the Annual Investment Allowance, the 50% first-year allowance for special-rate plant and IETF — mapped honestly for HVAC.
Read guide → meesMEES, EPC and Commercial HVAC — What the Rules Mean for Your Building
EPC E to let now, proposed EPC B by 2031 for larger buildings — how MEES drives commercial HVAC upgrades, and what to do about it.
Read guide → costWhat Drives Commercial HVAC Costs: A Buyer’s Breakdown
What commercial HVAC really costs by system: VRF, chillers, AHUs, ventilation and heat pumps, plus the factors that drive the price.
Read guide → f-gasF-Gas Regulations Explained for Commercial HVAC
Leak-check thresholds, company certification and the R410A-to-R32/R454B phase-down — the F-Gas rules that govern your commercial HVAC, in plain terms.
Read guide → maintenancePlanned vs Reactive HVAC Maintenance — Which Costs You Less?
PPM contract or fix-on-failure? The real cost comparison, contract types and the statutory F-Gas leak-check duty you cannot skip.
Read guide → vrfVRF vs Chiller — Which Commercial Cooling System Is Right?
VRF or a central chiller for your building? When each wins on cost, capacity and application, compared clearly for facilities managers.
Read guide → heat pumpsCommercial Heat Pump vs Gas Boiler — the Honest Running-Cost Comparison
Heat pump or gas boiler for your commercial building? The SCOP maths, running-cost reality and the MEES driver, compared without the spin.
Read guide → Ventilation guideCommercial kitchen extraction and ventilation: what the rules and guidance expect
No single law sets kitchen extract design, but HSE guidance, DW/172, TR19 Grease and council planning rules do. Canopies, make-up air, interlocks and cleaning.
Read guide → Tax and fundingCapital allowances on commercial HVAC: what businesses can claim
HVAC is usually an integral feature in the special rate pool. How the AIA, the 50% first-year allowance and the replacement rules apply to an HVAC project.
Read guide → Cooling guideServer room cooling requirements: temperatures, sizing and resilience
ASHRAE's recommended inlet range is 18 to 27°C. How to size server room cooling from IT load, when close control is worth it, and what to monitor and maintain.
Read guide → Compliance guideAC inspection, F-gas check or service: what to book and when
AC systems over 12kW in England and Wales need an energy inspection at least every five years. Who can do it, what it covers, how it differs from F-gas checks.
Read guide →