MVHR vs PIV - Which is the Best Ventilation System for Your Home?
Choosing the best ventilation system for your home can be confusing, especially when comparing Mechanical Ventilation with Heat Recovery (MVHR) and Positive Input Ventilation (PIV). Homeowners want to know which option will offer better air quality, ease of installation and lower energy bills.
MVHR is often viewed as the more advanced solution because it supplies fresh air and recovers heat from outgoing air, which can improve efficiency in modern, well-sealed homes.
PIV is simpler to install, works well to control damp and condensation, and suits older or less airtight properties. The best choice depends on the type and age of the property, as well as your priorities for comfort, efficiency and cost.
Key takeaways
MVHR suits modern, airtight homes where heat recovery can perform well
PIV is a simple, effective option for lived-in and older homes that need better damp control
The right system depends on your property’s layout, airtightness and budget
What is Mechanical Ventilation with Heat Recovery (MVHR)?
MVHR is a whole-home ventilation system that extracts stale air from bathrooms, kitchens and utility rooms while supplying filtered fresh air to living areas and bedrooms. Inside the unit, a heat exchanger transfers warmth from the outgoing air to the incoming air without mixing the airstreams. The goal is steady fresh air and reduced heat loss.
How it works
Stale air is extracted from wet rooms
Fresh outdoor air is filtered and supplied to living spaces
Heat is transferred from outgoing to incoming air via a heat exchanger
Ductwork distributes air throughout the house
Typical components
Component
Purpose
Heat exchanger
Transfers warmth to supply air
Fans
Drive extract and supply airstreams
Filters
Capture dust and pollen
Ductwork
Balances extract and supply to each room
Controls
Set speeds, boost and filter reminders
Benefits of MVHR
Cleaner indoor air by constantly replacing stale air with filtered supply
Temperature stability because recovered warmth tempers incoming air
Whole-home coverage with balanced extract and supply
Humidity management that helps reduce condensation risk in airtight homes
Considerations for MVHR
Requires a full duct network and careful commissioning
Works best in airtight, well-insulated homes
Needs regular filter changes and access for maintenance
Retrofit can be disruptive in lived-in properties
Which homes suit MVHR?
MVHR performs best in new builds and deep retrofits that are well insulated and airtight, with space for duct runs and access for maintenance. In older, draughty properties the benefits may be limited and retrofit can be challenging because of the ductwork required.
Home type
MVHR suitability
Modern new build
★★★★☆
Renovated to high spec
★★★☆☆
Traditional older home
★☆☆☆☆
What is Positive Input Ventilation (PIV)?
PIV is a whole-home approach that gently introduces filtered, fresh air into the property, usually from a central unit in the loft or, in flats, from a wall unit. The steady, low-energy airflow dilutes humid, stale air and encourages it to leave through natural leakage paths and purpose-made outlets. The result is better background ventilation that helps tackle condensation, damp and black mould.
Where it goes
Loft-mounted unit supplying a central landing in most houses
Wall-mounted unit for flats or homes without suitable loft space
How it helps
Provides a constant supply of filtered air
Dilutes humidity to reduce window condensation and mould growth
Supports fresher-smelling rooms and more stable conditions
Benefits of PIV
Condensation control across the whole home
Quick, tidy retrofit with minimal disruption and little or no ductwork
Low running needs with straightforward filter care
Works with existing extraction, for example high-performance extractor fans in bathrooms and kitchens
Considerations for PIV
Does not recover heat from outgoing air
In very airtight new builds, balanced systems may offer finer control
Performance relies on keeping exhaust paths available, such as trickle vents and good bathroom extraction
Which homes suit PIV?
PIV is a strong fit for lived-in and older properties, homes with persistent condensation, and buildings where installing full ductwork is impractical. It does not rely on very high airtightness to be effective, and it complements local extract fans in wet rooms.
Situation
PIV recommended?
Hard to install ducting
Yes
Older or less airtight home
Yes
Need to tackle condensation or damp
Yes
Highest heat-recovery priority
No, consider MVHR
MVHR vs PIV: side-by-side
Core idea
MVHR: Balanced extract and supply with heat exchange
PIV: Positive pressure supply that dilutes humidity and stale air
Best suited to
MVHR: Airtight new builds and major refurbishments
PIV: Existing and older homes, simple retrofits
Installation
MVHR: Full duct network and careful commissioning
PIV: Single central unit with minimal disruption
Condensation control
MVHR: Good in airtight homes
PIV: Very strong whole-home background control
Running needs
MVHR: Fans and filters with periodic maintenance
PIV: Low-power fan with simple filter care
Works with local extract
MVHR: Yes
PIV: Yes, often paired with high performance fans
Disruption during install
MVHR: Higher
PIV: Low
Aftercare
MVHR: Filter changes and balance checks
PIV: Filter checks and general ventilation good practice
Retrofit and installation considerations
Space and access
MVHR needs space for the main unit and routed ducts to each room. Older homes may lack ceiling voids for tidy runs.
PIV typically needs only a loft location or a wall position for the unit and a ceiling diffuser.
Fabric and airtightness
MVHR rewards airtightness and high-spec insulation.
PIV tolerates typical levels of leakage found in lived-in housing.
Time on site
MVHR first-fix and second-fix stages align with major refurb or new build.
PIV is usually a short installation with minimal making good.
Complementary measures
Both systems benefit from good bathroom and kitchen extraction. Condensation Cured can specify high-performance extractor fans to clear steam at source.
Comfort, noise and maintenance
Comfort
MVHR tempers incoming air through heat exchange for stable temperatures in airtight homes.
PIV supplies filtered air at a gentle rate. Drier air helps reduce the cold-film effect on windows and walls linked to surface condensation.
Noise
Both approaches are designed to run quietly when correctly installed and commissioned.
PIV units are typically sited in lofts or hallways to minimise perception of fan noise.
Maintenance
MVHR requires filter changes and occasional balancing checks.
PIV needs simple filter care and general ventilation good practice, such as keeping extract routes available.
Cost overview
Rather than headline prices, focus on scope and disruption:
MVHR involves a unit, supply and extract ductwork, terminals, commissioning and ongoing access. Planning is critical, which suits new build and deep refurbishment.
PIV involves a central unit and diffuser and usually connects quickly with little fabric disturbance. This suits occupied homes where a simple route to better background ventilation is preferred.
Condensation Cured PIV services
For most lived-in UK homes, PIV is often the simpler, more cost-effective choice because it retrofits quickly, needs little disruption and does not require whole-house ductwork. A single loft or hallway unit supplies filtered fresh air that dilutes humidity and helps prevent condensation and black mould with low running needs. Condensation Cured will survey your property, size the right unit and install it neatly.
Learn more on PIV installation services or call 0800 433 2063. Where helpful, PIV is paired with high-performance extractor fans to clear steam at source.
What happens at a PIV survey and install
Home survey to understand rooms, moisture patterns and access.
Unit sizing and siting so airflow reaches key spaces.
Neat installation of the unit and diffuser with minimal disruption.
Commissioning and settings explained in plain English.
Aftercare guidance on ventilation habits and filter checks.
Ask about the 60 day money back guarantee on qualifying PIV installs where condensation is not resolved once the heater option has been fitted or explored. Details and conditions apply on the PIV page.
Practical tips that help both systems
Keep bathroom and kitchen extraction effective and use boost while cooking or showering
Avoid drying clothes indoors where possible, or use local extraction if you must
Maintain background ventilation paths so stale air can leave
Wipe and monitor known cold spots during colder months to catch issues early
Frequently asked questions
Which is better, PIV or MVHR?
Neither is universally better. MVHR can offer strong efficiency and balanced ventilation in airtight, duct-ready homes. PIV is usually the better fit for existing properties that need reliable condensation control without major building work.
What are the disadvantages of PIV?
PIV does not recover heat. In colder months you may notice cooler supply air if the home is very draughty, although correct placement and settings help. Keeping background extract routes available, such as trickle vents and good bathroom fans, supports performance.
Can you open windows with MVHR?
Yes, but leaving windows open for long periods can reduce the benefit of balanced ventilation and heat recovery. Short periods for rapid airing are usually fine.
Do PIV units make a house cold?
PIV introduces outdoor air at a gentle rate. In most homes the effect is modest, and the benefit of drier air reduces condensation on cold surfaces. Correct commissioning and using good local extraction help maintain comfort.
Do I need trickle vents with PIV?
Trickle vents or other exhaust paths are helpful so stale air can leave as fresh air is supplied. In bathrooms and kitchens, strong local extraction supports the whole-home effect.
Do I need trickle vents with MVHR?
A well-installed MVHR is a balanced system, so additional trickle vents are not usually required and can upset balance if left open.
Can Condensation Cured install MVHR?
Condensation Cured focuses on PIV and complementary extraction for condensation control in lived-in homes. If you are considering MVHR for a new build or deep retrofit, discuss your plans with your designer or an MVHR specialist. For practical whole-home condensation control in existing properties, speak to us about PIV installation services.
How soon will I notice a difference with PIV?
Many homes notice fresher air and reduced window condensation soon after commissioning. Results build as the background environment stabilises, especially when paired with good daily extraction habits.