Published · Updated · By the MVHR Expert engineering team
The four options
- MVHR — balanced supply and extract with heat recovery
- MEV (Mechanical Extract Ventilation) — continuous extract from wet rooms, fresh air via trickle vents
- PIV (Positive Input Ventilation) — a fan, usually in the loft, pushes filtered air into the home
- Extractor fans — local, intermittent extraction in kitchens and bathrooms
How they compare
The comparison below is a general guide; the right choice depends on the property, airtightness and budget.
- Heat recovery: MVHR yes; MEV, PIV and extractor fans no
- Filtered supply air: MVHR and PIV yes; MEV and extractor fans no
- Ducting needed: MVHR substantial; MEV moderate; PIV minimal; extractor fans small
- Best for: MVHR in airtight homes; MEV in moderately airtight; PIV in older, leakier homes with condensation problems
Which should I choose?
In a very airtight new build, MVHR is typically the right choice and is often specified from the outset. For older homes with damp issues, PIV or MEV can be more practical. We service, repair and replace existing MVHR units; if you're considering a new system, a ventilation designer or installer can advise on the best fit.