Are you struggling to choose between MVHR and PIV for your home’s ventilation? With airtight modern properties and growing concerns about damp, condensation, and mould, the right system can make a huge difference.
Mechanical Ventilation with Heat Recovery (MVHR) extracts stale air, filters it, and reuses heat to create a healthier, energy-efficient indoor climate. Positive Input Ventilation (PIV), on the other hand, pushes in fresh filtered air and drives out humidity through natural pathways.
In this blog, we’ll explore MVHR vs PIV – which is the best ventilation system, comparing their benefits, drawbacks and helping you decide which option best suits your home.
What is MVHR?
Mechanical Ventilation with Heat Recovery (MVHR) is an advanced whole-house ventilation system designed to provide continuous fresh air while recovering heat from the outgoing stale air. It works by extracting humid, polluted air from kitchens, bathrooms, and utility rooms, then passing it through a heat exchanger.
This recovered warmth is transferred to the incoming fresh, filtered air before being distributed to living areas. MVHR is especially effective in modern airtight homes, improving air quality while reducing energy waste.
What are the Benefits of MVHR?
MVHR provides homeowners with improved comfort, lower energy bills, and cleaner indoor air. It’s particularly effective in airtight homes where natural ventilation is limited.
Energy Savings
By recovering heat from outgoing air, MVHR reduces heating costs and improves energy efficiency throughout the home.
Enhanced Air Quality
MVHR filters incoming air, removing dust, pollen, and pollutants, making it ideal for allergy and asthma sufferers.
Comprehensive Coverage
The system provides balanced ventilation across all rooms, ensuring fresh air circulation in both living areas and wet rooms.
Environmental Impact
MVHR lowers a household’s carbon footprint by recycling heat and reducing fuel consumption for a more eco-friendly home.
What are the Drawbacks of MVHR?
MVHR is highly efficient, but certain limitations may make it less suitable for every household.
Higher Cost
Installation costs are relatively high, though long-term energy savings can help offset this investment.
Airtightness Requirement
MVHR is less effective in draughty or poorly insulated homes, where heat recovery benefits are reduced.
Complex Installation
The system requires extensive ductwork and careful planning, which can be disruptive in existing homes.
What is PIV?
Positive Input Ventilation (PIV) is a straightforward and cost-effective ventilation system that improves indoor air quality by introducing fresh air into the home, usually drawn from the loft. This constant flow of filtered air creates positive pressure, which pushes out stale, humid air through natural leakage points and trickle vents.
By reducing excess moisture, PIV helps prevent condensation, damp, and mould. It’s a low-maintenance solution suitable for many homes, particularly older properties with ventilation and dampness issues.
What are the Benefits of PIV?
PIV offers simple, cost-effective improvements in ventilation, making it ideal for households experiencing damp, mould, or condensation issues.
Affordability
PIV is a budget-friendly option, offering effective ventilation at a fraction of the cost of advanced systems.
Ease of Installation
It can be installed quickly with minimal disruption, usually in the loft, without the need for complex ductwork.
Condensation Reduction
PIV reduces humidity and prevents condensation, helping to tackle dampness and mould in older or poorly insulated homes.
Adaptability
The system works well in various property types, particularly those with natural ventilation gaps like chimneys or vents.
What are the Drawbacks of PIV?
PIV offers an affordable solution, but it also comes with compromises that should be considered.
No Heat Recovery
Unlike MVHR, PIV does not recycle heat, which can increase heating costs in colder climates.
Dependence on Natural Gaps
It relies on natural leakage points, making it less effective in modern airtight or highly insulated homes.
Basic Filtration
PIV provides only basic air filtration and may not deliver the same high air quality improvements as MVHR.
MVHR vs PIV – Which is the Best Ventilation System
Choosing between MVHR and PIV depends on your property type, budget, and priorities. Here are the key differences so you can see how each system performs.
Installation
MVHR requires ductwork and detailed planning, making it more suitable for new builds or major refurbishments. Although it can be disruptive, it ensures full-house coverage.
On the other hand, PIV installation is simple to install and usually limited to a single loft unit. As a result, it is quick to fit and causes little disruption to the household.
Cost
MVHR involves a higher upfront investment with ongoing maintenance requirements. However, over time, the energy savings can help offset the initial expense.
In contrast, PIV is more affordable with minimal running costs. This makes it the budget-friendly option for homeowners seeking quick improvements.
Heat Recovery
MVHR recycles heat from outgoing air, reducing heating demand and improving overall energy efficiency in modern airtight homes. This feature makes it particularly attractive for households focused on sustainability.
PIV does not include heat recovery, which may slightly increase heating costs, especially during the colder months of the year. Therefore, it may be less efficient in the long run.
Air Filtering
MVHR provides advanced filtration, helping to remove allergens, dust, and pollutants for a healthier indoor environment. This makes it a stronger choice for families with allergy or asthma concerns.
Meanwhile, PIV relies on basic filtration that depends on the quality of incoming air. It improves airflow but offers less purification overall.
Energy Efficiency
MVHR is highly efficient and works best in airtight homes where heat recovery can be maximised. For this reason, it is often the preferred option in energy-efficient new builds.
By comparison, PIV may increase heating demand slightly but still improves airflow and reduces problems with damp and stale air.
Humidity Control
MVHR provides consistent humidity control across the whole home, helping to prevent condensation and mould. This makes it effective in maintaining a balanced indoor climate.
Similarly, PIV also reduces humidity but relies on natural leakage points in the property to push stale air outside. As such, its effectiveness depends on the home’s structure.
Suitability
MVHR is most effective in new builds and well-insulated homes where airtightness allows it to perform at its best. It is particularly suited to modern housing developments.
In contrast, PIV is better suited for older, draughty homes where positive pressure can circulate fresh air more easily. This makes it a flexible solution for traditional properties.
Conclusion
Choosing between MVHR and PIV depends on your property, budget, and ventilation needs. MVHR offers advanced heat recovery, energy savings, and cleaner air, making it ideal for modern airtight homes. PIV, on the other hand, is more affordable, easier to install, and well-suited to older, draughty houses. Both systems improve air quality, reduce humidity and help address issues like damp and condensation.
If you’re still unsure about MVHR vs PIV – which is the best ventilation system for your home, VentSolve can help. As Ireland’s trusted ventilation specialists, we provide expert advice, customise solutions, and professional installation. Contact VentSolve today to create a healthier, more comfortable living environment.
Frequently Asked Questions
What is the main difference between MVHR and PIV?
MVHR recovers heat from outgoing air and filters incoming air for cleaner, more efficient ventilation. In contrast, PIV introduces fresh air under positive pressure but does not recycle heat.
Is MVHR more energy-efficient than PIV?
Yes, MVHR is more energy-efficient because it recovers and reuses heat. PIV improves airflow but may slightly increase heating demand in colder weather.
Which system is cheaper, MVHR or PIV?
PIV is usually cheaper to buy, install, and run while, MVHR has higher upfront costs but can reduce energy bills in the long term.
Can MVHR be installed in older homes?
MVHR works best in modern, airtight homes. In older or draughty properties, its efficiency drops, making PIV a more suitable option.
Does PIV improve indoor air quality?
PIV helps by reducing humidity and condensation but only offers basic filtration. MVHR provides more advanced air purification by filtering allergens and pollutants.
How do I know which system is right for my home?
MVHR is ideal for new builds and airtight homes focused on energy savings. PIV is better for older, draughty homes where a simpler, cost-effective solution is needed.
