MVHR vs Extract Ventilation: Which Is Right for Your London Home?
If you are comparing MVHR vs extract ventilation, you are likely trying to understand which system is right for your home.
At first glance, the difference seems straightforward.
One is simple. The other is more advanced.
But in practice, the decision is rarely about the system itself.
It depends on how your home is being upgraded, how airtight it will become, and what level of comfort you are trying to achieve.
Choose the wrong approach, and you can end up with condensation, stale air, or a system that never quite performs as expected.
Choose the right one, and the house simply feels better to live in.
Why Ventilation Matters More in Retrofit
Most period homes in London were built to manage moisture and air movement passively.
Open chimneys, leaky windows, and permeable materials allowed air to move through the building.
When you retrofit a home, this changes.
Insulation is added. Gaps are sealed. Windows are improved.
The house becomes warmer and more stable. But it also becomes less forgiving.
Moisture from everyday living no longer escapes as easily. Without a clear ventilation strategy, it begins to accumulate.
This is when problems start to appear:
Condensation on windows
Persistent humidity in bathrooms and kitchens
Mould forming in corners or behind furniture
Air that feels heavy or stale
Ventilation is no longer something the building does on its own. It has to be designed.
For a broader overview, see our guide to ventilation strategies in period homes.
What Is Extract Ventilation?
Extract ventilation focuses on removing moisture and pollutants at source.
Typically, this means extracting air from:
Bathrooms
Kitchens
Utility spaces
This can be done intermittently or continuously through a low-level system.
Fresh air then enters the home through background vents and the natural permeability of the building fabric.
The system removes stale air, but does not actively manage how fresh air is supplied or distributed.
Where it works well:
Homes that remain relatively leaky
Smaller refurbishments
Situations where disruption or budget is limited
A well-designed extract system is simple, robust, and often entirely appropriate.
What Is MVHR?
MVHR, or Mechanical Ventilation with Heat Recovery, is a whole-house ventilation system.
It extracts stale air and supplies fresh air in a controlled way.
Air is removed from wet rooms, while fresh air is delivered to living spaces and bedrooms.
The key difference is heat recovery.
Warmth from the outgoing air is transferred to the incoming air through a heat exchanger. The air itself does not mix, but the heat is retained.
In lived terms, this means:
Fresh air without cold draughts
More stable internal temperatures
A consistent environment across the home
You can explore this further in our guide to MVHR in London homes.
Key Differences Between MVHR and Extract Ventilation
The differences are less about technology, and more about how the home performs as a whole.
Air quality
Extract ventilation improves conditions in specific rooms.
MVHR provides consistent air quality across the whole house.
Heat retention
Extract systems remove warm air and bring in cooler outside air.
MVHR retains much of that heat.
Installation and integration
Extract systems are relatively simple to install.
MVHR requires ductwork and early design coordination.
Disruption
Extract can often be added with minimal disruption.
MVHR is best installed during major works.
Cost
Extract is typically lower cost.
MVHR requires greater upfront investment.
Suitability for retrofit
Extract suits less airtight homes or partial upgrades.
MVHR suits well-insulated, more airtight homes.
When Extract Ventilation Is the Better Choice
Extract ventilation is often the right solution when the scope of work is limited.
For example:
A light refurbishment
A home that will remain relatively leaky
Budget prioritised elsewhere
Limited space for duct routes
In these cases, improving moisture control at source is often enough.
It is a practical solution that matches the level of intervention.
When MVHR Is the Better Choice
MVHR becomes more appropriate when the building itself is being significantly upgraded.
For example:
A deep retrofit
Improved insulation and airtightness
Major refurbishment works
A focus on long-term comfort and air quality
In these homes, MVHR supports the performance of the building.
But it only works well when the building is prepared for it.
What Most People Get Wrong
The most common mistake is starting with the system.
MVHR or extract.
In reality, this is the wrong question.
Problems arise when:
MVHR is added to a home that is still too leaky
The system is introduced too late in the design
Ventilation is treated in isolation
Systems are specified without understanding the building
The result is often poor performance or unnecessary complexity.
This is not a system problem.
It is a sequencing problem.
The Right Approach: Start with the Whole House
Before choosing a ventilation system, it is essential to understand the building.
How it performs now, and how it will perform after the work.
A fabric first retrofit approach focuses on improving the building itself:
Insulation
Airtightness
Thermal performance
Once this is addressed, the ventilation strategy becomes clearer.
You can explore this further in our guides to fabric first retrofit and home retrofit.
The system should support the building, not compensate for it.
How to Decide What’s Right for Your Home
There is no single answer.
The right approach depends on:
The scope of your project
Your budget
Your long-term goals
In many cases, the real question is not:
“MVHR or extract?”
It is:
“What does this home need to work properly?”
Next Steps
If you are weighing up these options, you are already asking the right questions.
The next step is to understand your home as a whole.
At Studio CMA, our Retrofit Strategy Service helps you:
Understand how your home performs
Plan the right sequence of improvements
Choose systems that work with the building
From there, decisions like MVHR or extract become clear.
You can:
The aim is not to choose a system.
It is to create a home that is comfortable, healthy, and performs well over time.
