Commercial MVHR: A Guide to Heat Recovery Ventilation for Non-Domestic Buildings

Key Takeaways

  • Commercial MVHR systems recover up to 93% of heat from exhaust air, significantly reducing heating demand in offices, schools, care homes, and retail buildings
  • Unlike domestic units, commercial MVHR must handle higher airflow rates, larger duct runs, and integration with cooling, BMS controls, and fire dampers
  • Non-domestic ventilation rates under Building Regulations Part F require 10 litres per second per person or 1 litre per second per square metre — whichever is higher
  • System selection depends on building type, occupancy patterns, and whether cooling recovery is required alongside heating
  • Commercial MVHR is increasingly specified for projects targeting BREEAM Excellent, net zero carbon, and compliance with the Future Homes and Buildings Standards

Introduction: Why Commercial MVHR Is Different

If you've read our MVHR Buying Guide, you'll know how heat recovery ventilation works in homes — a central unit extracts stale air from wet rooms, passes it through a heat exchanger to recover warmth, and supplies pre-heated fresh air to living spaces.

Commercial MVHR uses the same core principle, but the application is fundamentally different. Non-domestic buildings present challenges that residential systems simply aren't designed for:

  • Higher airflow rates. A small office might need 500 m³/h; a school classroom block might need 3,000–5,000 m³/h. Domestic MVHR units typically max out at around 600–700 m³/h.
  • Variable occupancy. A lecture theatre might be full one hour and empty the next. Commercial systems must modulate airflow in response to CO₂ levels, occupancy sensors, or BMS schedules — not just run at a fixed rate. Browse our fan controls and sensors for compatible control options.
  • Cooling as well as heating. Many commercial buildings need cooling recovery in summer. Commercial MVHR units with integral cooling coils or bypass modes handle both seasons.
  • Integration with other building services. Commercial MVHR sits within a wider M&E design alongside heating, cooling, fire safety, and building management systems. It needs to interface with BMS, fire dampers, smoke control systems, and potentially chilled water or DX cooling circuits.
  • Regulatory complexity. Non-domestic ventilation rates, CIBSE guides, BREEAM credits, and local authority requirements all influence system selection.

This guide covers what specifiers, M&E contractors, and facilities managers need to know when selecting commercial MVHR.

How Commercial MVHR Works

The operating principle is the same as residential MVHR: two airstreams — supply and extract — pass through a heat exchanger without mixing. Heat transfers from the warmer stream to the cooler one.

In winter, this means the outgoing warm exhaust air pre-heats the incoming cold fresh air. In summer, the process can work in reverse — cool exhaust air absorbs some of the heat from hot incoming air, reducing cooling load. This is sometimes called free cooling or summer bypass, depending on how the system is configured.

Key Components of a Commercial MVHR System

Air Handling Unit (AHU) with heat recovery: The central unit containing the heat exchanger, supply and extract fans, filters, and (often) heating and cooling coils. Commercial AHUs are significantly larger than domestic MVHR units and are typically installed in plant rooms.

Heat exchanger types:

  • Plate heat exchangers (crossflow or counterflow) — the most common type in commercial MVHR. Counterflow designs achieve higher efficiencies (up to 90–93%). No moving parts, low maintenance.
  • Rotary (thermal wheel) heat exchangers — use a slowly rotating wheel to transfer heat between airstreams. Higher efficiencies possible (up to 85–90%) and can transfer some moisture (latent heat recovery), which helps control humidity. Slightly higher maintenance due to the rotating element.
  • Run-around coils — two separate coils connected by a pumped water/glycol circuit. Less efficient (50–70%) but useful where supply and extract ductwork can't be co-located. Common in retrofit situations.

Ductwork: Rigid galvanised steel ductwork to DW/144 standards is standard for commercial installations. For an introduction to ductwork types, sizing, and materials, see our guide: What Is Ducting? Types, Sizes & Materials Explained. Duct sizing, pressure drop calculations, and acoustic attenuation all need careful design — especially in occupied spaces like offices and classrooms where noise is critical. We stock a full range of duct connectors and fittings and flexible ducting for branch connections.

Controls: Commercial MVHR is typically controlled via the building management system (BMS). CO₂ sensors, temperature sensors, occupancy detectors, and time schedules all feed into the control strategy. Browse our fan controls and sensors range, including Systemair controllers designed for both residential and commercial applications. Demand-controlled ventilation (DCV) is increasingly standard — as noted in our Future Homes Standard guide, this approach modulates ventilation rates based on actual need rather than running at full capacity 24/7.

Fire and smoke dampers: Where ductwork passes through fire compartment walls or floors, fire dampers are required to maintain fire resistance. In buildings with smoke ventilation requirements, the MVHR system must be designed to work alongside (or shut down in response to) the smoke control strategy. For more on how ductwork integrates with building construction, see our guide: What Is Ducting in Construction?

Grilles, diffusers, and terminal devices: Supply air enters rooms through ceiling or wall-mounted diffusers; extract air leaves through grilles and valves. In commercial installations, the choice of terminal device affects both airflow distribution and noise levels. We also offer bespoke made-to-order grilles and louvres for projects requiring non-standard sizes or finishes.

When to Specify Commercial MVHR

Commercial MVHR makes sense in most non-domestic buildings where people occupy spaces for extended periods. The strongest cases include:

Offices

Office buildings are the classic application for commercial MVHR. Occupancy is predictable, heating and cooling loads are significant, and the building regulations ventilation rates (10 l/s/person) mean substantial air volumes need conditioning.

For offices, look for MVHR systems with:

  • Counterflow plate heat exchangers for maximum efficiency
  • Integral cooling coils or connection points for chilled water
  • CO₂-based demand-controlled ventilation
  • Low specific fan power (SFP) to minimise energy use — CIBSE Guide L recommends SFP below 1.6 W/(l/s) for supply and extract systems

Schools and Education Buildings

Building Bulletin 101 (BB101) sets specific ventilation requirements for classrooms — typically 5 l/s/person with a maximum CO₂ concentration of 1,500 ppm. MVHR with CO₂-controlled DCV is increasingly the standard approach for new school builds.

Schools also benefit from the acoustic properties of well-designed MVHR — properly attenuated supply air is significantly quieter than opening windows on a busy road. For a practical overview of ventilation in education settings, see our guide: Extractor Fans for Schools.

Care Homes and Healthcare

Care homes require careful humidity and temperature control, and the occupants are often more vulnerable to poor air quality. MVHR with high-grade filtration (ePM1 55% or better) provides cleaner air than natural ventilation while maintaining warmth. For more on why indoor air quality matters, see our article on ventilation health and safety in buildings.

For healthcare environments, refer to HTM 03-01 for specific ventilation requirements — some clinical spaces require single-pass air rather than recirculation, which limits heat recovery options.

Retail and Hospitality

Retail spaces with high occupancy density benefit from MVHR, particularly in managing the balance between fresh air supply and heating/cooling energy. Restaurants and commercial kitchens have specific requirements — see our MVHR Systems for Commercial Kitchens collection for kitchen-specific systems.

Commercial MVHR with Cooling

One of the most searched terms in this space is "commercial MVHR with cooling" — and for good reason. In modern, well-insulated commercial buildings, cooling is often a bigger challenge than heating.

There are several approaches:

Summer bypass: The simplest option. When outdoor air is cooler than the building's exhaust air, a bypass damper diverts incoming air around the heat exchanger so it enters the building at ambient temperature. This provides free cooling but only works when outdoor temperatures are below indoor temperatures.

Integral cooling coil: A chilled water or DX cooling coil built into the AHU downstream of the heat exchanger. This actively cools the supply air. Requires connection to a chiller or VRF system.

Night purge ventilation: The MVHR system runs at elevated rates overnight to flush stored heat from the building fabric. Works well in heavyweight construction (concrete frame) and can significantly reduce next-day cooling demand.

Active cooling recovery: In summer, the heat exchanger works in reverse — transferring coolness from the conditioned exhaust air to the incoming warm supply air, reducing the load on the active cooling system.

The right approach depends on the building's thermal mass, internal heat gains, glazing ratio, and the client's budget. For most commercial offices and schools, a combination of summer bypass and an integral cooling coil provides the best year-round performance.

Sizing Commercial MVHR

Commercial MVHR sizing is more complex than domestic. It's based on a combination of:

Ventilation rate requirements:

  • Building Regulations Part F: 10 l/s/person or 1 l/s/m² (whichever is higher)
  • BB101 for schools: 5 l/s/person with CO₂ monitoring
  • CIBSE Guide A: provides detailed ventilation rates by building type and room function
  • Project-specific requirements: BREEAM, client briefs, local authority conditions

Heating and cooling loads: The heat recovery effectiveness directly affects the building's heating and cooling energy calculations. A system recovering 90% of heat from the exhaust air substantially reduces the peak heating load — and therefore the size of the heating plant.

Pressure drop: Longer duct runs and more complex distribution networks mean higher pressure drops. The AHU fans must be sized to overcome the total system pressure — including ductwork, filters, heat exchanger, silencers, and terminal devices. This directly affects specific fan power (SFP) and running costs.

Acoustic requirements: In noise-sensitive spaces (offices, classrooms, bedrooms in care homes), the AHU selection, duct sizing, and attenuator specification all need to achieve acceptable noise levels. CIBSE Guide B4 provides criteria — typically NR 30–35 for offices and NR 25–30 for classrooms.

Typical Sizing Examples

Building Type Floor Area Occupancy Required Airflow Typical AHU Size
Small office 200 m² 20 people 200 l/s (720 m³/h) Compact AHU
Medium office 1,000 m² 100 people 1,000 l/s (3,600 m³/h) Modular AHU
Primary school (6 classrooms) 800 m² 210 pupils + staff 1,200 l/s (4,320 m³/h) Modular AHU
Care home (40 beds) 2,000 m² 60 residents + staff 2,000 l/s (7,200 m³/h) Large modular AHU
Retail unit 500 m² Variable 500–1,000 l/s Depends on peak occupancy


These are indicative figures only. All commercial MVHR systems should be designed by a competent M&E engineer to CIBSE guidelines.

Regulations and Standards

Commercial MVHR sits within a well-defined regulatory framework:

Building Regulations Part F (Ventilation): Sets minimum ventilation rates for non-domestic buildings. The 2021 update clarified requirements for mechanical systems and introduced stronger emphasis on demand-controlled ventilation. Our Future Homes Standard guide covers the direction of travel — non-domestic requirements are tightening alongside residential.

Building Regulations Part L (Conservation of fuel and power): Heat recovery systems directly contribute to Part L compliance by reducing the building's heating energy demand. The heat recovery efficiency and specific fan power both feed into the building's energy model.

CIBSE Guides: CIBSE Guide A (environmental design criteria), Guide B2 (ventilation and ductwork), and Guide B4 (noise control) are essential references for commercial MVHR design. TM23 covers commissioning of HVAC systems.

BREEAM: A well-designed commercial MVHR system contributes to BREEAM credits under Hea 02 (Indoor Air Quality) and Ene 01 (Reduction of energy use and carbon emissions). Heat recovery with DCV is often necessary to achieve BREEAM Excellent or Outstanding.

The Future Buildings Standard: Like the Future Homes Standard for residential, the Future Buildings Standard will tighten energy and ventilation requirements for non-domestic buildings. Commercial MVHR with high-efficiency heat recovery positions buildings well for these upcoming changes.

Commercial MVHR Products Available from eFans

While large-scale commercial AHUs are typically project-specified through manufacturers like Systemair, there are several commercial MVHR applications where our stocked products are the right fit:

For Small Commercial Spaces (Offices, Clinics, Small Retail)

The Vent-Axia Sentinel Kinetic Plus B (488 m³/h) and Sentinel Econiq S (370 m³/h, up to 93% heat recovery) are suitable for small commercial applications — particularly offices and consulting rooms where the ventilation requirement is within the unit's capacity. Both are available from eFans with next-day delivery.

The Zehnder ComfoAir Q600 (up to 600 m³/h) handles larger small-commercial spaces and offers app-based monitoring and control. Browse the full Zehnder heat recovery range for all available models.

For Commercial Kitchens

See our dedicated MVHR Systems for Commercial Kitchens collection — these units work alongside kitchen extract systems to recover heat while maintaining fresh air supply in demanding food service environments.

For Larger Commercial Projects

For buildings requiring airflow rates above 600 m³/h, you'll need a project-specified AHU from manufacturers like Systemair, S&P, or Nuaire. We stock a wide range of commercial extractor fans from these brands — including commercial axial fans, inline duct fans, and roof fans — that complement commercial MVHR installations. For full AHU project supply, get in touch at projects@efans.co.uk to discuss your requirements and we'll provide competitive pricing and lead times.

Commercial MVHR vs Domestic MVHR — Key Differences

Feature Domestic MVHR Commercial MVHR
Typical airflow 100–700 m³/h 500–50,000+ m³/h
Heat exchanger Counterflow plate Plate, rotary wheel, or run-around coil
Cooling capability Summer bypass only Bypass + active cooling coils
Controls Standalone controller or app BMS-integrated with CO₂/occupancy DCV
Ductwork Rigid plastic or semi-rigid Galvanised steel to DW/144
Fire safety Basic fire dampers Full fire and smoke damper strategy
Noise control Low-velocity diffusers Attenuators, acoustic lining, duct sizing to NR criteria
Typical cost (unit only) £800–£3,000 £5,000–£50,000+
Typical installed cost £2,500–£6,000 £15,000–£150,000+
Design responsibility Installer or homeowner M&E consulting engineer

Installation Considerations

Plantroom Requirements

Commercial MVHR AHUs need adequate plant space with:

  • Sufficient floor area for the unit plus maintenance access on all sides
  • Structural support for the unit weight (large AHUs can weigh several hundred kg)
  • Acoustic isolation from occupied spaces — anti-vibration mounts and flexible connections
  • Fresh air intake and exhaust discharge points on the building exterior, separated to prevent short-circuiting. External weather louvres protect intake and discharge openings — we offer standard and bespoke made-to-order louvres in a range of sizes

Ductwork Design

Commercial ductwork design follows CIBSE Guide B2 and DW/144 standards:

  • Duct sizing balances air velocity (affects noise) against duct dimensions (affects ceiling void depth and cost)
  • Main supply and extract ducts are typically galvanised steel; branches may be flexible ducting or semi-rigid. Browse our duct connectors and fittings for standard connections
  • All duct penetrations through fire compartments require fire dampers to BS EN 15650
  • Insulation is required on supply ductwork to prevent condensation and heat loss

Commissioning

Commissioning is critical for commercial MVHR — a system that isn't properly balanced will underperform and waste energy. CIBSE TM23 sets out the commissioning process:

  • Verify airflow rates at all terminals match the design specification
  • Check supply and extract balance — the system should be slightly negative to prevent condensation in the building fabric
  • Measure specific fan power and compare to design values
  • Verify heat recovery efficiency under operating conditions
  • Test all control sequences — CO₂ response, time schedules, fire alarm shutdown
  • Document everything for the O&M manual and building log book

Frequently Asked Questions

What is the difference between commercial and domestic MVHR?

Scale, complexity, and integration. Commercial systems handle higher airflow rates, include active cooling, integrate with building management systems, and must comply with non-domestic ventilation standards. Domestic MVHR is a self-contained unit with simple controls — commercial MVHR is an engineered system designed as part of the building's M&E strategy.

Can I use a domestic MVHR unit in a small office?

Yes, for very small offices (up to about 6–8 people), a high-capacity domestic unit like the Vent-Axia Sentinel Kinetic Plus B (488 m³/h) can work. The key is to ensure the unit's capacity meets the non-domestic ventilation rate requirement (10 l/s/person or 1 l/s/m²). For anything larger, you need a purpose-designed commercial system.

How much does commercial MVHR cost?

The unit cost alone ranges from around £5,000 for a small compact AHU to £50,000+ for a large modular unit serving a multi-storey building. Fully installed costs (including ductwork, controls, commissioning, and builders' work) typically run from £15,000 for a small office to £150,000+ for a large school or commercial building. The payback comes through reduced heating and cooling energy — typically 3–7 years depending on the building and energy prices.

Does commercial MVHR replace air conditioning?

Not directly. MVHR recovers heat (and to some extent, coolness) but doesn't generate cooling. In many well-insulated modern commercial buildings, MVHR with summer bypass and night purge can significantly reduce the need for active cooling — but most offices and retail spaces will still need some form of mechanical cooling for peak summer conditions. The MVHR system reduces the size and running cost of that cooling plant.

What maintenance does commercial MVHR need?

Filters should be changed every 3–6 months depending on the environment (more frequently in urban or industrial locations) — for more on why this matters, see Why Do MVHR Filters Need Changing?. Heat exchangers need annual cleaning — our guide on keeping your MVHR clean covers the process. Fan belts (if fitted) need regular inspection. BMS sensors should be recalibrated annually. The full system should be recommissioned annually to verify airflow rates haven't drifted. For a broader view of best practices, see our ventilation system maintenance guide. A well-maintained commercial MVHR system will last 15–25 years.

Is commercial MVHR required by Building Regulations?

Heat recovery isn't explicitly mandated, but it's very difficult to achieve Part L compliance in new non-domestic buildings without it. The energy modelling will almost always show that MVHR is necessary to meet the carbon reduction targets. For BREEAM-rated buildings, it's effectively essential for achieving Excellent or Outstanding ratings.

Next Steps

If you're specifying commercial MVHR for a project, we can help:

  • Small commercial spaces: Browse our whole house MVHR range — units like the Vent-Axia Sentinel Kinetic Plus B and Zehnder ComfoAir Q600 suit offices and small commercial applications
  • Commercial kitchens: See our MVHR Systems for Commercial Kitchens collection
  • Project supply: For larger commercial projects requiring AHUs from Systemair, S&P, or Nuaire — contact us at projects@efans.co.uk for project pricing and lead times
  • Technical advice: Not sure which system suits your building? Get in touch at hello@efans.co.uk and we'll help

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