What is PIV (Positive Input Ventilation) & why do we need a ventilation system?

Over the last decade there has been increasing demand on builders, architects, and government legislation to increase the thermal efficiency of our homes making them draught free and well insulated. This has caused poorer air quality that can significantly increase the effects of asthma and other respiratory problems, health problems, condensation, mould, dust mites, unpleasant smells, and build-up of toxic gases. 

For health reasons Government legislation now makes it almost compulsory for your new airtight home to have a balanced mechanical ventilation system.

What is Positive Pressure Ventilation?

A positive input pressure ventilation unit (PIV) is a loft or wall mounted unit that pushes fresh filtered air throughout the property to combat condensation via a ceiling mounted diffuser normally fitted in the hallway.

How does it work?

The units continually introduce a subtle filtered air supply from the trapped heat and fresh air from your roof void via a ceiling mounted diffuser normally in your hallway and redistributes the heat trapped at ceiling level. The moist, stale air is then forced out of the property through natural ventilation points (window trickle vents).


The perfect solution for hard to cure mould and condensation properties. Improving indoor air quality and preventing moisture build-up within the home. Backed up with a 5-year maintenance free guarantee. PoziDry Pro™ improves indoor air quality and quickly eradicates conditions that lead to mould growth, reducing the risk of health issues in the home. The unit is unobtrusive, near silent running and has low operating costs.
Loft mounted positive input fan draws fresh air from the atmosphere, filters it and pushes it into the dwelling via a ceiling mounted diffuser. All stale air in the property is forced out through the natural forms of ventilation, such as window mounted trickle vents and bathroom extractor fans.
Can also be used for building control system 3 (whole house ventilation) if used with continuous running bathroom fans (DMEV)

Key Features:

  • Temper Heater is highly effective at reducing condensation and mould
  • simple to install and commission
  • Selectable air capacities to suit floor areas up to 150m2
  • Uses the latest Lo-Carbon motor technology for low running costs
  • Ultra-low sound level
  • Complete with ceiling diffuser, flexible duct, and worm drive clips
  • Standard 5-year guarantee
  • Up to 5-year maintenance free G4 filter
  • Anti-vibration Legs offer flexibility when fitting and guarantee silent running
  • Flexible Feet – allow the PoziDry Pro™ to be installed across two joists or along joist offering
  • Moulded Handle – Makes carrying PoziDry Pro™ safe and simple. The handle also allows you to change the pitch of the PIV if hanging kit is used
  • Filters- PoziDry Pro™ is unique in offering F7 filters which filter down to PM2.5 which includes harmful diesel particulates
  • Smart Sense™ Technology – Easy set up and smart data logging capabilities all accessed via the intuitive 3 button menu
  • IPX2 rated and Under assessment with BBA


The 500W heater is fully flexible and has the option to be installed at diffuser level to reduce heat loss through the ducting. This means more heat enters the habitable areas of the house. Smart Sense controls allow the Pozidry Pro to be adjusted fully when the heater is activated making it adaptable for all lifestyles.


The Lo-Carbon PoziDry pro uses a sensor to monitor the temperature in the loft, automatically adjusting the air volume when necessary. The unit will continuously ventilate silently in the background whilst in ‘Trickle’ mode. Once the unit automatically senses excess heat being lost into the loft the airflow will increase to ‘Normal’ mode to recover heat that would otherwise be lost through the roof. During summer months should the loft exceed 27°C the unit will enter ‘stand-by’
mode in order stop the circulation of warm air allowing for a more comfortable living environment.
PoziDry Pro Heater models automatically turn on the 500W heater to boost air temperature by 10°C during colder months. Under assessment with BBA.


Up to 5-year maintenance free G4 filter as standard (PM10 filtration) which filters out many everyday pollutants such as pollen & dust.
Optional F7 filters are available (PM2.5 Filtration) removing tobacco smoke, diesel particulates, spores, and a number of bacteria.


The unit can be controlled by Smart Sense™ Technology – Easy set up and smart data logging capabilities all accessed via the intuitive 3 button menu on the unit.
Speed control selection is easy. Once house size is selected based on number of bedrooms, PoziDry Pro automatically selects the correct Trickle and Normal speeds. Should you need to adjust speed manually this can be done easily.

Data Logger allows the unit to record how long it has been running in each of its speeds. It also measures the number of days the product has been switched on to provide precise running information. Smart Sense technology can also record the duration of heater activity and energy used.


The Lo-Carbon PoziDry Pro features a specially developed Lo-Carbon DC fan/motor arrangement which runs quietly and delivers incredibly low running costs of less than £3 per year to run, the motor operating temperature is -25/40`c


The Lo-Carbon PoziDry Pro is uniquely flexible in its installation methods, high sided anti vibration legs and a hanging kit both come as standard, allowing the PoziDry Pro to be installed quickly in any sized loft.
The easy carry handle incorporated into the body makes carrying the unit easy and safe; especially useful when lifting the unit through loft hatches.
The unit is supplied with a purpose designed diffuser to be located over the stairwell of a conventional dwelling or in the main hall of a bungalow.
Using Smart Sense technology, the unit is easily set to the appropriate speed at installation based on the size of the dwelling. Background ventilation openings provide the exhaust points.
En-suites and utility areas should be serviced by continuous mechanical extract ventilation.