Commercial HVAC: FAQs

Commercial HVAC is the heating, ventilation and air conditioning plant that keeps a commercial building comfortable, healthy and open, everything from VRF/VRV air conditioning and central chillers to air handling units (AHUs), ventilation and MVHR, commercial heat pumps and the planned maintenance (PPM) that keeps it all running and compliant. A specialist designs these as a joined-up system: efficient cooling and ventilation, electrified low-carbon heating, and indoor air quality, sized to the building's real loads rather than a like-for-like box swap.

VRF (Variable Refrigerant Flow, also called VRV) uses one or more outdoor condensers to modulate refrigerant to many indoor units, each zone controlled independently, and suits offices, retail and hotels up to roughly 150-200 kW of cooling. A chiller produces chilled water that is pumped to AHUs and fan-coils, and scales far beyond VRF for large offices, hospitals, data suites and process loads, or where long pipe runs rule out direct-expansion. Heat-recovery VRF can move heat from cooling zones to heating zones simultaneously; chillers win on large central loads. Many buildings use both, VRF on the office floors, a chiller for a data or process load.

Not banned outright for existing larger systems, but squeezed. R410A has a high global warming potential (around 2,088), and the GB F-gas phase-down is steadily reducing the supply of high-GWP refrigerants, so R410A gas will get scarcer and more expensive over time. From 1 January 2025, new single-split systems under 3 kg charge could not use refrigerant of GWP 750 or more in Great Britain, a clear signpost for larger equipment. The sensible approach is to keep existing plant maintained and leak-tight, plan its replacement around end of life, and specify low-GWP refrigerant, R32 (GWP 675) or R454B (around 466), when you renew.

If your system contains F-gas refrigerant, leak checks are a legal duty once the charge reaches 5 tonnes of CO2-equivalent (at least annually), 50 tonnes (six-monthly) or 500 tonnes (quarterly), with automatic leak detection reducing some frequencies. The work must be done by an F-gas certified company (REFCOM, Quidos F-Gas Register or Bureau Veritas) and certified engineers, and refrigerant records must be kept. The Environment Agency enforces these rules. Most commercial VRF and chiller systems cross the 5-tonne threshold, which is exactly why leak checks are a core part of a PPM contract.

In most buildings, yes, and it's the electrification step in a sensible HVAC strategy. Air-source or water-source heat pumps deliver heat at a seasonal efficiency (SCOP) of typically 2.8-4.0, removing on-site combustion and giving a credible route to net-zero heat. The best results come from lowering flow temperatures (45-55C), upgrading emitters where needed and recovering ventilation heat, which is why we survey and model rather than swap like for like. Where a full switch isn't yet affordable, a hybrid or staged approach keeps a peaking boiler while the heat pump does the bulk of the work. Note the domestic £7,500 Boiler Upgrade Scheme does not apply to commercial buildings.

It depends on the SCOP and your tariff, and it should be modelled from your real consumption. Electricity is currently around four times the unit price of gas (roughly 24-25p versus 6-7p per kWh on 2026 price caps), but a heat pump's SCOP of 2.8-4.0 offsets most of that, at an SCOP of around 3.5, a unit of heat costs close to or slightly below a good gas boiler today. Low flow temperatures, ventilation heat recovery and a sensible tariff are the levers. Where the maths is genuinely marginal we say so, and often recommend efficiency measures first. As the Climate Change Levy and grid decarbonisation shift the balance, the electrified case improves over time.

There is no commercial equivalent of the £7,500 Boiler Upgrade Scheme, that scheme is domestic-only. Commercial HVAC is funded mainly through the tax system: full expensing gives companies a 100% first-year deduction on qualifying new plant (made permanent from April 2026), the £1m Annual Investment Allowance covers other businesses, and a new 40% first-year allowance applies from 1 January 2026. Eligible energy-intensive industrial and data-centre sites could historically use the Industrial Energy Transformation Fund, though its remaining windows are winding down, so we confirm current status rather than promise it. We map the routes that genuinely apply to your building.

It depends on the technology and the building. As a guide: VRF/VRV systems typically run £20,000-£250,000; central chillers £80,000-£1.5m+; air handling units £15,000-£400,000; ventilation and MVHR £8,000-£200,000; and commercial heat-pump heating £60,000-£600,000. Cost is driven by the cooling and heating load, the number of zones and units, plant-room and access constraints, refrigerant choice and any electrical supply upgrade, not floor area alone. We model the full installed cost, and the whole-life running cost, from a proper survey before you commit, and can stage the work where a single capital hit isn't affordable.

PPM stands for Planned Preventative Maintenance, scheduled visits (usually quarterly or six-monthly) that keep your HVAC plant efficient, compliant and running. A good PPM contract does three things at once: it handles your statutory F-gas leak checks and records so you stay legal, it catches faults early through servicing and remote monitoring before they become expensive reactive call-outs, and it protects manufacturer warranties (many require documented maintenance). For most commercial buildings the contract costs less than the breakdowns, efficiency losses and compliance risk it prevents. We price PPM against your actual plant and its F-gas leak-check frequency.

Often refurbish, and it should be a survey-led decision. Many ageing AHUs are strong upgrade candidates: retrofitting EC (electronically commutated) fans, replacing tired coils, adding or improving heat recovery and upgrading filtration can cut fan energy significantly and improve indoor air quality for far less than a full replacement and its disruption. Replacement is the honest answer where the casing is corroded, the layout is wrong, or the building's duty has changed. We give you the whole-life cost of each option, so it's a numbers decision rather than a default rip-out.

Heavily, because heating, cooling and ventilation dominate a commercial building's modelled energy use. Since 1 April 2023 it has been unlawful to continue letting commercial space below EPC E, and the government has proposed EPC B by 2031 for privately rented non-domestic buildings over 1,000 sqm (subject to secondary legislation; the floated 2027 interim EPC C was dropped). Efficient VRF/chillers, heat recovery on ventilation, better controls and electrified low-carbon heat all lift the modelled performance that sets the EPC, so an HVAC upgrade is often the most effective route to protecting the lettability of a larger building.

Ventilation and air handling are what deliver clean, fresh, correctly-conditioned air, so indoor air quality (IAQ) is an HVAC outcome, not a separate product. AHUs filter incoming air (F7/ePM filtration), MVHR recovers heat while bringing in fresh air, and demand-controlled ventilation (CO2 and occupancy sensing) supplies fresh air where and when it's needed. Good IAQ supports productivity, wellbeing and infection control, and the design trick is to deliver it without a heating and cooling penalty, which is exactly what heat recovery and demand control achieve. We design ventilation for IAQ and energy together, not one at the expense of the other.

Low-GWP refrigerants, so the plant is not stranded by the F-gas phase-down. For most new VRF and DX systems that means R32 (GWP 675) or R454B (around 466), both far below R410A's ~2,088. Chillers increasingly use R32, R454B, R1234ze or, for smaller duties, natural refrigerant R290 (propane, GWP 3), which sits outside the F-gas quota entirely. Natural and flammable refrigerants carry DSEAR and siting requirements, which we design for. Specifying low-GWP now avoids future gas-supply cost and compliance risk, and all refrigerant work is carried out by F-gas certified engineers.

Possibly, so we check early. Electrified cooling and heat pumps add meaningful electrical load, and where a DNO supply upgrade is needed it can be the longest-lead item in the whole project. We confirm your available supply capacity at the feasibility stage, and on constrained sites look at phasing, demand management, or pairing the HVAC with on-site solar and battery storage to keep within capacity. Getting this conversation started early is what stops the electrical supply becoming the thing that delays the install.

It varies with scale and technology. A VRF retrofit on an office floor is often a few weeks on site once design and any electrical work are agreed; a central chiller or a major AHU replacement can run several weeks to a few months including craneage, plant-room works and commissioning; and a heat-pump heating changeover is planned around your operating calendar, typically spring or autumn, with the old plant kept live through commissioning where possible. The DNO supply upgrade, where one is needed, is frequently the longest-lead item, which is why we start it at feasibility.