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Solution guide

Positive input ventilation (PIV)

Positive Input Ventilation can improve whole-home background ventilation where condensation is widespread. It needs the property and moisture pattern to be suitable.

Is it right for my problem?Diagnose first
Where this solution fits

When positive input ventilation (piv) makes sense

Look for a diagnosis and pattern that genuinely match the job this solution is designed to do.

✓Whole-house condensation patterns
✓Stale air and persistently high humidity
✓Properties where local extraction alone is not enough
What it will not do

Know the limitations before you buy

The wrong treatment can hide a symptom while the actual moisture source continues.

Compare damp causes
01

Not a repair for water ingress

Check this limitation against your home before deciding this is the right route.

02

Performance depends on installation and dwelling layout

Check this limitation against your home before deciding this is the right route.

03

Still needs effective wet-room extraction

Check this limitation against your home before deciding this is the right route.

Before you spend

Three checks worth making first

1
Confirm condensation is the main problemUse the result to confirm scope and avoid treating the wrong moisture mechanism.
2
Review existing ventilation provisionUse the result to confirm scope and avoid treating the wrong moisture mechanism.
3
Get the system sized and positioned correctlyUse the result to confirm scope and avoid treating the wrong moisture mechanism.
Check likely work scope
DampDeck solution guide

Positive input ventilation (PIV): how to use it properly

What it does

Introduces filtered air to dilute indoor humidity in suitable homes.

When it can make sense

Can help some whole-home condensation patterns after basic defects are addressed.

Important limitation

Suitability depends on layout, loft/duct options, airtightness and the actual moisture source.

Evidence & reviewDampDeck reviewed this guidance on 3 September 2026. UK government guidance says damp and mould should be addressed by identifying and correcting the underlying moisture cause; surface mould removal alone does not prevent recurrence.UK Government source →
Before you choose it

Make sure the solution fits the cause

A technically good product or system can still be the wrong answer if the moisture source has been misdiagnosed.

1

Confirm which moisture source the solution is intended to control.

2

Check what preparation, installation and maintenance are required.

3

Ask what the solution cannot fix and what evidence should improve after installation.

Where it fits

Can help some whole-home condensation patterns after basic defects are addressed.

Important limitation

Suitability depends on layout, loft/duct options, airtightness and the actual moisture source.

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Useful products for this stage

Only products that support the investigation or an appropriate fix are shown here. An active leak or building defect still needs repairing.

Investigation toolsRelevant productInvestigation toolsBrowse on Amazon →Repair toolsRelevant productRepair toolsBrowse on Amazon →
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Products and equipment that fit this solution

Contextual products are useful only where they match the diagnosed problem. DampDeck does not present a product as a cure for an active leak or building defect.

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Relevant to Positive input ventilation (PIV)

PIV & ventilation

DampDeck only surfaces products that make sense for this stage of the investigation. Products do not replace diagnosis or repair of an active leak.

DampDeck may earn commission from qualifying purchases or referrals.

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Professional installation or investigation

Need a specialist rather than a product?

Search by town or postcode for the trade that matches the likely cause and proposed work.

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