Ventilation & Indoor Air Quality comparisons
Ventilation strategies that protect health and the building fabric, compared like for like.
MVHR & ventilationMVHR vs PIV (Positive Input Ventilation)
MVHR is a balanced, heat-recovering system best suited to airtight, well-insulated homes; PIV is a simpler, lower-cost system that dilutes humidity by pressurising the house but recovers no heat. The right choice depends mainly on how airtight your home is and what problem you are solving.
Read comparisonMVHR vs MEV (Mechanical Extract Ventilation)
MVHR is a balanced supply-and-extract system that recovers heat and filters incoming air; MEV is extract-only and relies on uncontrolled inlets to make up the air. In an airtight, well-insulated home MVHR is the correct choice because it ventilates fully while saving the ventilation heat. MEV suits leakier homes, or where ducting a full supply network is impractical, and is a step up from intermittent fans — but it loses heat and cannot filter supply air.
Read comparisonMVHR vs Natural (Trickle) Ventilation
Natural ventilation is uncontrolled — it depends on wind, temperature and whether people open windows and vents — and it discards heat with the air. MVHR provides a controlled, continuous, filtered air supply and recovers most of the ventilation heat. In a leaky, traditionally built home natural ventilation can be adequate; in an airtight, well-insulated home it cannot reliably deliver fresh air without large heat losses, which is why MVHR becomes necessary.
Read comparisonContinuous vs Intermittent Extract Ventilation
Continuous extract removes moisture steadily all day and responds to humidity; intermittent fans only act in short bursts when triggered, leaving long unventilated gaps. For controlling condensation and indoor humidity, continuous (or demand-controlled continuous) extract is markedly more effective and is increasingly the default. Intermittent fans can be adequate in leakier homes with good background ventilation, but they routinely under-ventilate in practice.
Read comparisonIndoor Air Quality Monitoring vs Ventilation Assessment
Monitoring measures the symptom — what the air is actually doing — while a ventilation assessment diagnoses the system that produces it. The two work together: monitoring proves whether there is a problem and where, and the assessment explains the cause and the fix. Monitoring alone tells you the CO₂ is high but not why; an assessment without monitoring is theory without evidence.
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