Mechanical Ventilation with Heat Recovery in London Homes
Revised 21/02/2026
When MVHR is appropriate in period and refurbishment projects
Mechanical ventilation with heat recovery, usually shortened to MVHR, is one of the most controlled forms of domestic ventilation available.
It is not necessary in every home. In the right context, particularly during a significant refurbishment or deep upgrade, it can significantly improve comfort, air quality and energy performance.
Before deciding whether it is appropriate for your project, it helps to understand where it sits within the wider range of ventilation options available in older properties. Our guide to ventilation in period homes explains the full spectrum from simple extract fans to balanced heat recovery systems. This article focuses specifically on MVHR.
What MVHR Actually Does
MVHR is a balanced, whole-house ventilation system.
It continuously extracts stale air from kitchens, bathrooms and utility spaces while supplying filtered fresh air to living rooms and bedrooms.
Inside the unit, a heat exchanger transfers warmth from the outgoing air to the incoming air. The two air streams do not mix, but heat is retained. In well-designed systems, 70 to 90 percent of the heat can be recovered.
This reduces heat loss compared to extract-only systems, where warm air is simply expelled and replaced with cold outdoor air.
In dense urban environments, including many London terraces, MVHR also filters incoming air. For homes affected by traffic noise and pollution, this allows fresh air without opening windows onto busy streets.
Is MVHR Right for Your Project?
MVHR is most effective when:
Insulation levels are being significantly improved
Draughts and uncontrolled air leakage are being reduced
Ceilings or floors are already being opened up
A major extension or full refurbishment is underway
Long-term comfort and air quality are priorities
It is less effective in very leaky buildings where air continues to move through gaps in the fabric.
In many London period homes, MVHR becomes proportionate when it forms part of a coordinated upgrade rather than as a standalone intervention.
Retrofit Constraints in Period Homes
Installing MVHR in Victorian and Edwardian houses requires careful design.
Ductwork must run between the central unit and each room served. In new builds this is straightforward. In older terraces with limited ceiling voids, it requires planning.
Common constraints include:
Shallow floor and ceiling zones
Limited space for plant
Conservation area restrictions
The need to avoid visible bulkheads or awkward boxing
For this reason, MVHR works best when integrated early in the design process. If ceilings are already being removed for insulation or structural work, ducts can be coordinated cleanly. Retrofitting it later can be disruptive and compromise room proportions.
This is where early architectural planning becomes important. Duct routes, ceiling depths and plant space need to be considered alongside layout, structure and services.
Costs and Practicalities
Installed costs vary depending on layout complexity and the stage at which the system is introduced.
As a broad guide, a whole-house MVHR system for a typical London terrace often falls in the range of £3,000 to £6,000 when delivered as part of a wider refurbishment. Complex layouts or restricted access can increase this.
It requires:
Space for the unit, often in a loft or utility cupboard
Accessible filters for maintenance
Careful commissioning to balance airflow
Filters typically need replacing every 6 to 12 months.
Introducing MVHR during a planned refurbishment is typically simpler and less disruptive than retrofitting it into a completed interior.
Noise and Performance
A properly designed and commissioned MVHR system should be quiet.
Noise problems typically arise from poor duct sizing, tight bends or incorrect airflow balancing. Early coordination and correct installation are essential to ensure the system supports comfort rather than undermines it.
When MVHR May Not Be Proportionate
MVHR is not automatically the right solution for every project.
It may not be proportionate where:
The building remains highly permeable
The refurbishment is light-touch
There is no space for ductwork
Budget constraints favour simpler mechanical extract systems
In medium-depth upgrades, continuous mechanical extract or demand-controlled systems may provide adequate moisture control with less disruption. The appropriate choice depends on the overall ambition of the upgrade.
MVHR as Part of a Coordinated Upgrade
MVHR works best when integrated with insulation improvements, airtightness upgrades, heating system design and moisture management. In most projects it forms part of a broader, considered approach to upgrading an older home rather than a standalone technical add-on.
If you are thinking about improving comfort, energy performance and long-term resilience together, you may find our guide to a considered whole-house retrofit approach helpful.
If you are considering fabric upgrades, our guide to insulating a period home explains how insulation interacts with moisture and ventilation.
If you are preparing your property for lower-flow heating systems, our article on making your home heat pump ready sets out how airtightness, heat demand and ventilation need to work together.
Next Steps
Ventilation decisions are most effective when made in context.
If you are planning a significant refurbishment or deep upgrade, our Retrofit Strategy Service sets out how insulation, airtightness, ventilation and heating should be sequenced to improve comfort and manage moisture risk before detailed design begins.
An Architect’s Home Visit and Appraisal can help assess whether MVHR is proportionate for your building, layout and budget.
If you would like to discuss your project, you can book a free 45-minute Project Consultation.
Frequently asked questions
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MVHR is most effective in homes that are reasonably airtight and undergoing significant refurbishment. In lightly upgraded or very leaky buildings, simpler ventilation systems may be more proportionate.
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Yes, but it requires early planning. Duct routes and plant space must be carefully integrated. Installation is usually most practical during a full refurbishment or extension.
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As part of a wider refurbishment, installed costs often fall between £3,000 and £6,000 depending on layout complexity.
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A well-designed system should be very quiet. Noise issues typically arise from poor installation or incorrect commissioning.
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Filters are usually replaced every 6 to 12 months to maintain performance.
