Design & Consultancy · Ventilation, Cooling and Indoor Climate
Mechanical design and consultancy for design-led London buildings
A building's mechanical systems are settled long before anyone orders a fan or a condenser. Ceiling depths, riser positions, plant space and façade openings are all fixed during architectural design – and they either accommodate the ventilation, cooling and heating the occupants will need, or they quietly rule it out. Mechanical design is the discipline of resolving those questions on drawings, while every option is still open and every change is still a revision rather than a variation.
AVC Integrations provides that discipline as a consultancy service. We design ventilation systems from Mechanical Ventilation with Heat Recovery to targeted extract, air-conditioning strategies built on calculated heat loads, and – where a project genuinely calls for it – close humidity control for galleries, wine rooms and joinery-sensitive interiors. Because our designers also deliver and commission systems, the drawings we issue are ones an installer can build, a maintenance team can live with and an interior can absorb without compromise.
Photo location: AVC-EXP-MDC-01
AVC engineer at a workstation reviewing a coordinated mechanical model – ductwork, fan-coil units and pipe routes visible on screen, marked-up plans on the desk
Landscape · 16:9 · min 2400 px wide
Mechanical design consultancy is the engineering of a building's ventilation, cooling, heating and humidity-control systems on paper – calculated, coordinated with the architecture and documented before construction begins. AVC Integrations offers mechanical design as a standalone appointment or as part of a wider MEP scope, working with architects, developers, consultants and private clients on prime residential and high-end commercial projects across London.
The starting point
The problem: comfort designed from leftover space
When mechanical design lags the architecture, the systems inherit whatever space is left. Ventilation ducts get flattened until they whistle, cooling capacity is dictated by the shallowest void rather than the actual heat gains, condensers land wherever a neighbour or a planning officer will later object to them, and plant is buried somewhere no engineer can ever service it. None of these are installation faults – they are questions nobody answered at design stage, and by the time they surface on site the remedies involve structure, joinery and programme rather than a drawing revision.
London projects sharpen every one of these pressures. Basement plant rooms are fought over metre by metre, façades and roofs are constrained by planning, party walls put acoustics on the agenda from day one, and highly glazed interiors carry real overheating risk that Building Regulations Approved Document O now obliges design teams to confront. A mechanical designer who understands those constraints – and who has stood in the ceiling voids where such designs are built – changes what the finished building can be.
How AVC works
The AVC approach: one design for the whole indoor climate
We treat ventilation, cooling, heating and humidity as one interdependent design rather than separate packages. Fresh air comes first: a ventilation strategy – Mechanical Ventilation with Heat Recovery, whole-house supply and extract, or targeted extract where that is the honest answer – developed with Building Regulations Approved Document F in view and shaped around duct routes, riser space and intake and exhaust positions the façade can accept. Cooling and heating are then built on room-by-room load calculations: glazing, orientation, occupancy and equipment determine capacity, and capacity determines the VRV or VRF topology, condenser strategy and unit concealment that follow. Throughout, acoustics, energy performance and maintenance access are design inputs, not afterthoughts.
Humidification gets a shorter, more careful treatment – because it deserves one. Close humidity control matters where art, wine or fine joinery would suffer without it, and it brings real obligations in plant space, water treatment and condensation risk. We design it where the project genuinely needs it, size it through calculation, and say plainly when a simpler approach will serve the client better. That honesty runs through the whole appointment: every recommendation is one we would be prepared to install, commission and maintain ourselves.
Photo location: AVC-EXP-MDC-02
Mechanical design documentation in progress – heat-load calculation sheets, a ventilation schematic and duct-sizing notes laid out together
Landscape · 4:3 · min 1800 px wide
What we deliver
Scope of service
A mechanical design appointment can cover a single system or the complete indoor-climate scope. Typical work includes:
Ventilation design
- Mechanical Ventilation with Heat Recovery (MVHR) system design
- Whole-house supply-and-extract and extract-only strategies
- Ventilation strategy developed with Approved Document F in view
- Duct sizing, routing and riser planning
- Intake and exhaust positions resolved against façade, planning and acoustic constraints
- Attenuation and low-velocity design for quiet operation
Cooling and heating design
- Room-by-room heat-gain and heat-loss calculation
- VRV/VRF system strategy, zoning and condenser planning
- Concealed indoor-unit and grille strategy agreed with the interior design
- Heating interfaces – heat pumps, underfloor circuits and the wider heating strategy
- Humidification and close humidity control for galleries, wine rooms and joinery-sensitive interiors
- Controls philosophy, metering and zoning
Calculations and documentation
- Load, airflow and duct- and pipe-sizing calculations
- Overheating-risk input coordinated with Approved Document O assessments
- Schematics, plant schedules and coordinated layout drawings
- BIM-ready models for coordination with structure and other services
- Plant-space, electrical-supply and builders' work information
- Specifications, tender documentation and construction-stage review
Interfaces, resolved
Designed into the building, not onto it
Mechanical systems live or die in the gaps between disciplines – the void above a decorated ceiling, the riser shared with drainage, the roof zone the planning consultant is negotiating. Our design work happens inside those conversations, with routes, spaces and interfaces agreed on drawings while the architecture can still move.
- Ceiling voids, bulkheads and riser sizes agreed with the architect while ceiling zones are still negotiable
- Grilles and diffusers positioned with the interior designer, lighting and joinery – not after them
- Plant space and condenser locations resolved against planning, acoustics and maintenance access
- Duct and pipe routes proven against structure in the coordination model
- Condensate and drainage interfaces aligned with the public health design
- Electrical supplies, isolation and controls wiring defined for the electrical package
- Acoustic targets carried from the brief through selection, attenuation and layout
Photo location: AVC-EXP-MDC-03
Ceiling void on site showing MVHR ductwork and a concealed fan-coil unit installed neatly to the coordinated design
Landscape · 4:3 · min 1800 px wide
Where this applies
Project types
Prime houses and refurbishments
whole-house ventilation, cooling and heating designed within period fabric and new structure alike
Apartments and lateral conversions
shallow voids, shared risers and limited condenser options – resolved spatially before they become compromises
Galleries, wine rooms and collection spaces
close temperature and humidity control where the contents demand engineering discipline
High-end commercial
offices, restaurants and boutique hospitality where comfort and quiet are part of the offer
Delivery
How a mechanical design appointment runs
- 01
Brief and survey
comfort expectations, constraints and – on existing buildings – a survey of what is really there
- 02
Strategy
ventilation approach, cooling and heating topology, plant-space and condenser options tested against the architecture
- 03
Calculation
room-by-room loads and airflows that fix capacities, duct sizes and plant selections
- 04
Coordination
routes, voids and risers resolved with the architect, structural engineer and other designers in the model
- 05
Detailed design
layouts, schematics, schedules and specifications issued for pricing and construction
- 06
Construction support
review of contractor proposals, technical submittals and site queries as the design is built
- 07
Commissioning review
witnessing and proving the installed systems against the design intent before handover
Timing
Why early involvement matters
Every consequential mechanical decision is spatial before it is technical. Riser positions, void depths, plant areas and façade penetrations are set at concept and developed design – and once they close, the mechanical engineer is no longer designing a system but negotiating with a building. Brought in early, we can shape those decisions with numbers: how deep the voids genuinely need to be, where plant can sit without an acoustic argument, which ventilation strategy the fabric and the brief actually support.
The consultancy appointment is deliberately flexible. Some clients want a full design carried through to commissioning review; others want an independent check of a design already on the table, or an engineer alongside the architect for the early spatial decisions only. In every case, the drawing stage is where the argument is winnable.
Placeholder – project evidence
Project example to follow – a genuine AVC mechanical design commission with the client's permission. Drawings, photography and project details are being prepared.
Photo location: AVC-EXP-MDC-04
Finished design-led interior where the mechanical systems are invisible – only a discreet linear grille in the ceiling hints at the ventilation and cooling behind it
Landscape · 16:9 · min 1800 px wide
Connected expertise
Related services
Design & Consultancy
the full design scope – mechanical, electrical and public health
Daikin VRV Air Conditioning
how the cooling designs we produce get built and commissioned
MVHR & Mechanical Ventilation
delivery of the ventilation systems this page designs
MEP Design, BIM & Coordination
how mechanical design is resolved against every other service
Public Health Design
water supply, hot water and drainage designed alongside the mechanical scope
From the knowledge centre
Related engineering guides
MVHR Explained: The Complete Guide to Heat Recovery Ventilation
Modern airtight buildings can't breathe on their own. MVHR delivers continuous fresh, filtered air while recovering up to 90% of the heat you'd otherwise throw away – here's how to get it right.
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VRV vs VRF Air Conditioning: What's the Difference and Which Do You Need?
VRV and VRF are the same technology under two names – but choosing, sizing and designing the system correctly is where projects succeed or fail. Here's what actually matters.
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Part O Explained: The Overheating Rules Reshaping New Homes in London
The newest part of the Building Regulations is quietly redrawing façades across London. How the simplified method and CIBSE TM59 modelling actually work, why noise and security rules push most urban schemes into dynamic modelling, and where mechanical cooling legitimately fits.
Read articleQuestions, answered
Frequently asked questions
Do you offer design-only appointments?+
Yes. Mechanical design is available as a standalone consultancy service – we produce the calculations, drawings and specifications, and another contractor builds them. Many clients do go on to appoint AVC for delivery as well, but the design stands on its own and is documented so that any competent installer can price and build it.
Should we choose MVHR or extract-only ventilation?+
It depends on the fabric, the brief and the building's airtightness. Mechanical Ventilation with Heat Recovery rewards well-sealed, refurbished or newly built envelopes where recovered heat and filtered fresh air justify the duct space it needs; extract-only approaches can be the honest answer for leakier fabric or lighter refurbishments. We set out both options against the project rather than defaulting to either.
Do you deal with overheating and Approved Document O?+
Overheating risk is a design input from the first strategy discussion, especially on highly glazed London schemes. We coordinate our cooling and ventilation design with the project's overheating assessment under Approved Document O, and where a specialist assessor is appointed we make sure the mechanical strategy and the assessment tell the same story.
How are the cooling and heating loads calculated?+
Room by room, from the architectural information – glazing areas and orientation, fabric performance, occupancy and equipment. Those calculations decide capacities, and capacities decide unit selections, duct and pipe sizes and plant space. We do not size systems by rule of thumb, because on design-led buildings the rules of thumb are usually wrong in both directions.
How do you design for quiet operation?+
Acoustics are treated as a brief requirement, not a snag. That means generous duct sizing and low air velocities, attenuation where calculation shows it is needed, plant and condenser positions assessed for neighbours and bedrooms, and vibration isolation detailed at source. On projects with an acoustic consultant we design to their criteria; on others we set sensible targets with the client.
What deliverables does a mechanical design include?+
Typically load and airflow calculations, system schematics, coordinated layout drawings, plant and equipment schedules, specifications and builders' work information, with BIM models where the project is coordinated in three dimensions. The exact package is agreed at appointment and scaled to the project – a wine room needs a different set of documents from a whole house.
When is humidification actually worth designing in?+
When something in the building would be damaged without it – artwork, a serious wine collection, veneered joinery or instruments that need stable humidity. It is a project-specific decision made through calculation and an honest conversation about plant space, water treatment and maintenance. Where the need is not real, we say so and design the simpler system.
Can you review a design produced by someone else?+
Yes. We are regularly asked to review mechanical designs at tender or before construction – checking loads, spatial coordination, acoustics and maintainability, and flagging where the drawings will not survive contact with site. The output is a clear, prioritised report the design team can act on.
Start the conversation
Request a Mechanical Design Proposal
Share your drawings, programme or brief and our engineering team will come back with a considered view of scope and approach – and the decisions worth making while they are still cheap to make.