Not every home needs MVHR. But every home needs adequate ventilation

If your home feels stuffy in the morning, you regularly see condensation on windows, humidity remains high or you constantly need to open windows to get fresh air, it may be time to assess your ventilation.

The question is not simply:

“Which MVHR unit should I buy?”

The more important question is:

“Does my property need MVHR, and what ventilation system is appropriate for it?”

The answer depends on the building, its airtightness, layout, occupancy, existing ventilation and ventilation requirements.

When should you consider MVHR for your home?

MVHR may be worth considering when a property requires controlled mechanical ventilation and you also want to recover heat from extracted indoor air.

Typical situations include:

• a new-build property;
• a highly insulated or airtight home;
• a major renovation;
• a property with insufficient natural ventilation;
• bedrooms that become stuffy overnight;
• persistent condensation;
• high indoor humidity;
• recurring stale air;
• a need to keep windows closed because of noise or outdoor conditions.

These signs do not automatically mean that MVHR is required.

They indicate that the property’s ventilation should be assessed.

How do you know if your home has poor ventilation?

There is no single symptom that proves inadequate ventilation.

Instead, look for a combination of signs.

Stuffy air

If rooms regularly feel stale, particularly after spending several hours with the windows closed, air exchange may be insufficient.

Condensation

Regular condensation on windows can indicate high indoor humidity, although condensation can have several causes.

High humidity

Excess moisture is produced by everyday activities such as showering, cooking and breathing.

Without adequate ventilation, humidity can remain inside the property.

Bedroom air feels stale in the morning

A bedroom occupied overnight can experience a gradual increase in CO₂ and humidity if there is insufficient fresh-air exchange.

Persistent odours

If cooking smells, bathroom humidity or other odours remain in the property for long periods, the extraction system may need to be assessed.

Constantly opening windows

If you repeatedly need to open windows simply to make the air feel comfortable, this can be a sign that the existing ventilation strategy needs attention.

Is MVHR suitable for an existing house?

MVHR can be installed in some existing homes, but suitability depends on the property.

A retrofit MVHR installation needs to take into account:

• building construction;
• airtightness;
• available space;
• ceiling and floor construction;
• duct routes;
• room layout;
• number of occupants;
• existing ventilation;
• required airflow rates.

Ductwork is one of the most important practical considerations.

A whole-house MVHR system normally requires a network of ducts connecting the central unit to supply and extract terminals.

In some existing properties, installing this network can be straightforward.

In others, it may require careful planning or alternative solutions.

That is why a property assessment should come before choosing an MVHR unit.

MVHR for new builds

MVHR is particularly relevant during the design stage of a new home.

When the building is being designed, ventilation can be integrated into the architecture rather than added afterwards.

This makes it easier to plan:

• the MVHR unit location;
• duct routes;
• supply terminals;
• extract terminals;
• maintenance access;
• acoustic considerations;
• airflow requirements.

For a new-build property, ventilation should be considered alongside insulation, airtightness, heating and overall energy performance.

How is an MVHR system designed?

The MVHR unit is only one part of the ventilation system.

A properly designed MVHR installation involves several stages.

1. Assess the property

The first step is understanding the building.

This includes floor area, layout, number of occupants, room use and existing ventilation.

2. Calculate airflow requirements

The required airflows need to be established for the property and relevant rooms.

3. Select the appropriate MVHR system

The unit should be selected based on the required airflow, system characteristics and property requirements rather than simply choosing the largest or cheapest unit.

4. Design the ductwork

Duct diameter, routes, lengths, bends and connections can affect system performance and noise.

5. Position supply and extract terminals

Fresh air should be supplied to appropriate habitable rooms, while stale air is generally extracted from moisture-producing areas.

6. Balance the system

Supply and extract airflows should be measured and balanced during commissioning.

7. Maintain the system

Filters need to be checked and replaced according to the manufacturer’s recommendations.

This is why professional MVHR installation is about much more than mounting a ventilation unit on a wall or in a cupboard.

Why does MVHR system design matter?

Two properties with the same floor area can have very different ventilation requirements.

For example, a four-bedroom house with six occupants will have different ventilation needs from a two-bedroom home occupied by one or two people.

The layout also matters.

So do:

• room sizes;
• number of bedrooms;
• bathrooms;
• kitchen layout;
• occupancy;
• airtightness;
• ductwork possibilities.

This is why MVHR for homes should be designed around the property rather than selected purely by floor area.

 

What happens if MVHR is poorly designed?

An MVHR system can only perform as intended if the complete system is correctly designed and installed.

Poor design may result in:

• inadequate airflow;
• excessive noise;
• inefficient operation;
• poor air distribution;
• pressure imbalance;
• uncomfortable air movement;
• unnecessary energy consumption.

This is why system commissioning is important.

After installation, the designed airflow rates should be checked and adjusted where necessary.

Is MVHR better than opening windows?

MVHR and window ventilation serve different purposes.

Opening a window is a simple way to introduce fresh outdoor air.

MVHR provides controlled mechanical ventilation.

The advantages of MVHR can include:

• continuous ventilation;
• heat recovery;
• reduced reliance on open windows;
• controlled airflow;
  fresh-air supply to
• bedrooms and living spaces;
• extraction from bathrooms and kitchens.

However, windows can still be opened when occupants want to.

The choice is not necessarily “MVHR or windows”.

An MVHR system provides a continuous ventilation baseline, while windows can still be used according to personal preference and outdoor conditions.

Is MVHR worth the investment?

MVHR can be a worthwhile investment when a property benefits from controlled ventilation and heat recovery.

The value depends on several factors.

These include:

• the property’s airtightness;
• heating requirements;
• ventilation needs;
• building design;
• energy prices;
• installation cost;
• expected system lifespan;
• maintenance requirements.

For a highly airtight modern home, controlled mechanical ventilation can be an important part of the building’s overall performance.

For an older, leaky property, other ventilation improvements may sometimes be more appropriate.

The right answer therefore depends on the building rather than the technology alone.

MVHR Installation: what should you ask an installer?

Before choosing an installer, ask how they will approach the project.

Important questions include:

• Will the property be assessed before the system is selected?
• How will airflow requirements be calculated?
• How will the ductwork be designed?
• How will the system be balanced after installation?
• How will filters and maintenance be handled?
• Where will the supply and extract terminals be located?
• How will noise be controlled?

A professional installation should consider the entire ventilation system rather than focusing only on the central unit.

Do you need MVHR or another ventilation system?

MVHR is not automatically the correct solution for every property.

Depending on the building, alternatives may include other mechanical ventilation systems or improvements to existing natural ventilation.

The decision should take into account:

• property type;
• airtightness;
• ventilation requirements;
• available space;
• budget;
• installation complexity;
• energy-efficiency objectives.

 

The goal is not to install the most sophisticated system possible.

The goal is to provide the right level of ventilation for the property.

Frequently Asked Questions

Does every house need MVHR?

No. Every home needs adequate ventilation, but not every property requires MVHR. The appropriate ventilation system depends on the building, its airtightness, occupancy, layout and ventilation requirements.

Is MVHR suitable for an old house?

It can be, but an older property may have different airtightness and installation requirements from a modern home. A property assessment is recommended before selecting MVHR.

Is MVHR suitable for a new build?

Yes. MVHR can be particularly suitable for well-insulated and airtight new-build homes where controlled ventilation is required.

How much does MVHR installation cost?

The cost varies significantly depending on the property, system size, ductwork complexity, installation requirements and equipment selected. A property-specific quotation is more useful than a generic price estimate.

How long does an MVHR system last?

The lifespan depends on the equipment, installation, operating conditions and maintenance. Filters and other serviceable components require regular attention.

Does MVHR need maintenance?

Yes. Filters should be checked and replaced according to the manufacturer’s instructions, and the system should be maintained to ensure continued performance.

Is MVHR noisy?

A correctly designed and installed system should be designed to operate quietly. Noise depends on the equipment, airflow, ductwork, terminal selection and installation quality.

Can MVHR be installed without ducts?

A conventional whole-house MVHR system requires ductwork to distribute and extract air. Properties where installing ducts is difficult may require a different ventilation approach.

Choosing the right MVHR system starts with your home

The best MVHR system is not necessarily the most powerful or expensive one.

It is the system that is correctly matched to the building.

Before choosing equipment, consider:

property → occupancy → airflow → ductwork → system → installation → commissioning → maintenance.

If you are unsure whether your home has adequate ventilation, the first step is to assess the property rather than simply purchase a ventilation unit.

Need help choosing an MVHR system?

We can help assess your property’s ventilation requirements and recommend an appropriate MVHR system for your home.

Our approach considers the property, its layout, occupancy, ventilation requirements and practical installation conditions.

From MVHR selection and system design to installation and maintenance, we can help create a ventilation solution designed around your home.

Fresh air, controlled ventilation and heat recovery — designed for the way your home actually works.