MVHR Design for Sandbanks: High-Performance Ventilation for Luxury Properties

Sandbanks and the Dorset coastline host some of the most valuable, architecturally ambitious homes in the UK. Their scale, glazing, and specification demand an approach to ventilation that is as considered as the masonry, joinery and lighting. At the heart of a refined environmental strategy is a well‑designed Mechanical Ventilation with Heat Recovery (MVHR) system: it protects interiors from coastal humidity and salt, delivers consistently fresh air, recovers heat efficiently and—critically for these properties—does so with discretion and whisper‑quiet performance.

This long‑form guide drills deep into the design element of MVHR for luxury coastal properties. It’s written for architects, developers, and homeowners who will accept nothing less than engineering precision and aesthetic refinement.

The Challenge of Designing for a Coastal Environment

Protecting your investment from salt and humidity

Salt‑laden air is corrosive. Over years it accelerates degradation of metalwork, corrodes heat‑exchanger surfaces, and shortens the life of external grilles and intake louvres. Coastal humidity also creates a continuous condensation risk on cold surfaces and in concealed voids, threatening timber, leather, art, and high‑value finishes.

A marine‑attuned MVHR design approaches those hazards in three ways:

• Source control: position intakes away from prevailing winds, use louvres with rain and salt deflection, and incorporate a sacrificial external prefilter or intake hood to intercept the worst of sea spray.
• Material selection and placement: specify corrosion‑resistant metals (and avoid raw aluminium externally), choose stainless steel or protected finish for condensate trays and fixings, and locate the MVHR plant in a protected plant room where possible.
• Maintenance planning: design for easy access to filters, an accessible heat‑exchanger core for descaling/inspection, and a documented maintenance schedule that acknowledges a coastal service interval (typically more frequent than inland equivalents).

Ensuring quiet, discreet operation for a peaceful home

Luxury homes demand low mechanical signature. Noise and vibration from fans, ductwork, and terminal devices can undermine a carefully composed interior.

Effective acoustic design is not an afterthought; it is integrated from the start:

• target internal background noise levels under 25–30 dB(A) in bedrooms and quiet living areas;
• use low‑speed fans, anti‑vibration mounts, flexible connectors, and lined silencers in supply and extract runs;
• route ducts through insulated acoustic risers and away from bedrooms;
• adopt larger, slower ductwork where possible (lower velocity = lower noise and pressure loss).

In practice this means specifying units with low specific fan powers, designing duct velocities to be moderate (see the technical targets section below), and using high‑performance terminal diffusers that distribute air gently across wide apertures rather than point‑blowing into a room.

Our Expert Design Process in Dorset

Creating bespoke designs for grand new‑builds and ambitious renovations

A Sandbanks MVHR design begins with the architecture, not with the catalogue. We treat ventilation as a bespoke building service that must be choreographed around the house’s key spaces, view lines and joinery details.

Typical steps:

1. Preliminary brief & site reconnaissance. We assess the site orientation, prevailing wind and the nearest seaward exposures. For renovations we inspect existing voids, services risers and the feasibility of concealed plant rooms.
2. Architectural coordination. We work from early stage plans (RIBA Stages 0–2) so duct routes and risers are considered before finishes and furniture layouts are finalised.
3. Thermal and airflow modelling. For complex, glazed or double‑height spaces we use CFD and room‑by‑room load calculations so the MVHR distribution is balance‑engineered, not guessed.
4. Component selection & specification. We choose a heat‑exchanger, fans and filters sized to the property, with material and corrosion protection selected for coastal exposure.
5. Plant location and concealment strategy. Either a dedicated plant room, acoustic enclosure, or utility area is selected and modelled for access, maintenance and attenuation.
6. Commissioning and handover. Full airflow balancing, noise testing and handover documentation ensure performance matches design intent.

Collaborating with high‑end architects and developers in the area

We routinely partner with architects and developers across Poole, Bournemouth and Christchurch to integrate MVHR unobtrusively: linear diffusers concealed in ceilings, micro‑ducts within joinery, and plant rooms coordinated with lift shafts or underground garages. Early collaboration saves expensive rework and keeps the interior palette uninterrupted by mechanical clutter.

Design Elements: Materials, Units and Ducting

Unit selection for coastal luxury homes

• Heat‑exchanger type: plate heat exchangers are compact and high‑efficiency; however, because many cores are aluminium, we specify either corrosion‑protected cores or protected external siting. Where moisture control is critical, consider an enthalpy core (which transfers moisture) carefully—it can retain winter humidity but may also carry salt and odour if not well‑maintained.
• Construction & finish: choose units with stainless steel condensate trays and coated casings. External panels and external louvers should be marine‑grade or powder‑coated to resist salt spray.
• Capacity and redundancy: large properties may require multiple smaller units in parallel rather than a single very large unit—this improves redundancy, eases service access, and reduces on‑site vibration transfer.

Ducting choices and routing

• Rigid galvanised steel remains the best choice for primary ductwork internally; for coastal sites specify a protective coating and consider stainless steel for exposed runs. Avoid bare aluminium in exposed or external duct runs.
• Insulation and condensation control: all ductwork in unheated voids must be insulated with a vapour barrier and use closed‑cell insulation where condensation risk is high.
• Branching strategy: favour larger main trunks with carefully sized branched runs. For open‑plan living spaces, use multiple supply diffusers with low face velocities rather than a single high‑velocity outlet.

Acoustic Strategy: Achieving Whisper‑Quiet Performance

Acoustics and MVHR performance are inseparable in luxury properties.

Key tactics:

• Low‑speed fans and larger impellers reduce tonal noise.
• Acoustic attenuators sized to the frequency content of the fans prevent structure‑borne noise reaching rooms.
• Flexible connectors and anti‑vibration mounting for the MVHR cabinet isolate mechanical vibration from the structure.
• Longer, lined silencers on external inlets/extracts reduce wind and intake noise for seaside sites.

Acoustic outcomes should be validated at commissioning with in‑room sound level measurements and, if required, octave‑band analysis.

Humidity, Summer Mode and Seasonal Operation

Dorset summers are warm and occasionally humid; a Sandbanks MVHR design must therefore follow a seasonal strategy:

• Summer bypass & purge modes: allow for bypassing the heat exchanger at night to cool the property using cool night air; ensure the control strategy includes temperature and humidity thresholds.
• Humidistat control: automatic boost to extract areas when humidity spikes (bathrooms/kitchen) and staged suppression to avoid over‑drying.
• Active dehumidification: in extremely glazed or high‑occupancy scenarios, MVHR can be paired with discreet dehumidifiers or HVAC for humidity control—coordinate space and condensate drainage accordingly.

For summer humidity control on the Dorset coast, design the MVHR with good seasonal controls, an easy‑to‑operate manual override for owners, and a sensible integration with ASHP or cooling systems if present.

Commissioning, Testing and Ongoing Care

A luxury MVHR design is only as good as its commissioning and maintenance plan.

• Airflow balancing: measured at each terminal with a hood or anemometer to within design tolerances; adjust via calibrated dampers.
• Noise verification: measure in‑room background noise and compare to design targets.
• Filter and core inspection: filters in coastal properties should be checked 2–4 times a year (pre‑filters more often); fine filters and the core inspected and cleaned annually as a minimum.
• Handover pack: provide owners with an illustrated maintenance manual, filter part numbers, typical replacement frequencies and contact details for emergency service.

Specification Checklist (Designer’s Quick‑Reference)

• Design heat recovery efficiency target: >75–90% (specify unit tested to recognised standard)
• Internal background noise target: ≤25–30 dB(A) bedrooms; ≤35 dB(A) living spaces (site‑dependent)
• Duct velocities: keep branch velocities moderate (typical design range 2–4 m/s) to control noise and pressure losses
• Material protection: stainless or powder‑coated external elements; stainless condensate trays
• Filter strategy: G4 pre‑filter + F7 (or equivalent ISO ePM1) fine filter; consider higher protection for intake hoods
• Commissioning: full balancing, acoustic testing and written handover documentation

Example specification snapshot (500 m² contemporary Sandbanks residence)

• MVHR capacity: 600–1,200 m³/h (depending on occupancy and heat gains)
• Units: two parallel units (for redundancy) each ~600 m³/h
• Primary heat‑exchanger: counterflow plate with protective coating
• Filters: replaceable G4 pre‑filters changed quarterly; F7 fine filters changed 6–12 months
• Noise target: <25 dB(A) in primary bedrooms at normal operation
• Plant: located in ground‑floor plant room with acoustic door and anti‑vibration mounts

(This snapshot is indicative — every property requires a bespoke calculation.)