Fresh air is filtered
Loft-mounted systems normally draw air from a suitable, ventilated loft. Wall-mounted systems draw fresh air directly from outside.
Positive Input Ventilation explained
How does Positive Input Ventilation work?
Positive Input Ventilation (PIV) gently introduces fresh, filtered air into the home. Nuaire Drimaster loft systems use this principle to create a very small positive air pressure that encourages stale, humid air to leave through the home's existing ventilation routes.
The pressure difference is tiny. You will not feel the house becoming pressurised; the system is designed to create a gentle, continuous movement of air.
Continuous 16-second animation
See how a Nuaire Drimaster PIV system works
PIV introduces a continuous supply of fresh, filtered air and gently displaces stale, moisture-laden air.
Loft-mounted Drimaster ECOTired of waking up like this?
Fresh filtered air
Helps reduce condensation
Helps reduce the conditions that allow condensation related mould to develop
Improves indoor air quality
DryHome VentilationFresh air, less condensation.
Check your home’s suitability
Watch the gentle flow of fresh, filtered air through the home.
Fresh filtered airQuiet operationHelps reduce condensationHelps reduce condensation mould conditionsMay improve indoor air qualityLow running costs
Three simple stages
How PIV moves air through the home
Fresh filtered air enters the home
The air is supplied through a ceiling diffuser, usually positioned in a central hallway or landing.
Stale humid air leaves the property
As fresh air is introduced, stale humid air is gently displaced towards existing extract fans, trickle vents and natural leakage paths. It does not all leave through one outlet.
Put simply, PIV continually replaces stale humid air with fresh filtered air. This helps reduce excessive indoor humidity, condensation and the conditions associated with condensation mould.
Important limitations
What PIV does not do
- Cure rising damp
- Repair leaks
- Replace bathroom extractor fans
- Replace kitchen extractor fans
- Heat the house
PIV is intended to help manage indoor humidity and air quality. A different repair or ventilation approach may be needed where the moisture source is structural. Our condensation and mould guide explains the main differences.
Cold-weather comfort
What does a heated PIV unit do?
A Nuaire Drimaster Heat model gently tempers the incoming air during colder weather, helping reduce the sensation of a cool draught at the diffuser.
The integral heater is not central heating and is not designed to heat the house.
Compare Nuaire Drimaster standard and heated systemsChoosing an installation route
Loft-mounted and wall-mounted PIV
The right route depends on the property, available space and how fresh air can be introduced safely.
Loft Mounted
- Draws air from a suitable ventilated loft.
- Suitable where adequate loft access exists.
Wall Mounted
- Draws fresh air directly from outside.
- Often suitable for flats and properties without an appropriate loft.
Outside or ventilated loftFresh air
FilterCaptures airborne particles
PIV unitGently supplies air
Hallway diffuserCentral supply point
Bedrooms and living roomsFresh air moves quietly through the home
Humid air leaves through existing routes
Bathroom extractKitchen extractTrickle ventsNatural leakage
For more detail, read our PIV questions and answers or our guidance on ventilation and Northern Ireland Building Regulations.
Common signs
Is this happening in your home?
💧
Water running down windows
Heavy condensation after cold nights, cooking or showering.
✦
Black mould around windows or walls
Recurring surface mould linked to excess indoor moisture.
〰
Musty or stale smells
Air that feels heavy, stale or slow to clear.
☁
Excess humidity and poor air quality
A persistently damp or uncomfortable indoor environment.
From first question to installation
How the process works
Start online or speak to us directly. Both routes lead to the same careful property discussion and recommendation.
- 1
Complete the suitability check or contact us
Choose whichever route feels easiest.
- 2
Discuss the property
We review the home, symptoms, loft access and any photographs that may help.
- 3
Receive our recommendation
We explain which system may be suitable—or tell you if PIV is not the right approach.
- 4
Confirm price
We confirm the installed price and any property-specific requirements before you agree.
- 5
Book installation
Once you are happy to proceed, we agree a convenient installation date.
Which PIV system suits your home?
Use the 60-second online suitability check for an initial recommendation, or contact us directly and we will talk it through with you.