Positive Input Ventilation


We use the PAM Intelligent PIV LOFT, this is a loft mounted ultra quiet, low energy, low maintenance, home ventilation unit.

The unit is designed to help ventilate a home using the well-established Positive Input Ventilation (PIV) principle.

PIV units have been preventing and curing condensation dampness related problems in homes for decades. They are also used to control other indoor air pollutants and have even proven to be an effective means for reducing Radon gas in some properties.

The range of Intelligent PIV units, with their unique ECOLoFlo energy and comfort optimisation airflow control technology, represents a ‘step change in Ply technology.


External air is drawn into the loft by the Intelligent PIV LOFT unit. Before it passes through the unit’s filter, the air increases in temperature as it utilises otherwise unused energy in the loft from solar gain and heat loss from the home. This increase can be significant, but is typically around 3°C warmer than outside air over a heating season. This energy gain is significantly more than the energy used by the unit’s motor. The tempered, filtered air is then supplied centrally to the home via the unit’s outlet duct and ceiling diffuser.

Integral controls allow the Intelligent PIV LOFT unit to be set to suit the individual requirements of the home. Airflow from the unit to the home is automatically regulated via integral

temperature and humidity sensors which optimise the energy benefit of the unit while ensuring that sufficient air is always supplied to help control moisture and other pollutant levels in the home.


Discreet Small white plastic supply air diffuser which will blend well with any ceiling while distributing the air as required.

Low energy Ultra-low quiet fan/motor assembly.

Robust and lightweight Fan casing construction built to last.

Run Monitor Records time power supplied to unit.

Low maintenance Very large G4 grade filter.

Integral, multifunctional controls With wide airflow and temperature settings which allow the unit to be fine-tuned to suit the individual requirements of a home and its occupants. These controls include:

  • 8 unit settings to choose from to suit the size, layout, thermal properties and moisture production in the home.
  • Heat Recovery mode function with adjustable trigger temperature setting and adjustable increased airflow setting.
  • Standby mode which switches the unit off when the temperature reaches the pre-set Standby trigger temperature to save energy and prevent undesirable warm air being introduced unnecessarily in to the home. e.g. during hot summer days.
  • ECO-LoFlo function
  • Override Boost mode to operate the unit at its maximum airflow by means of a user switch.

Suspension kit and joist mounting brackets Supplied for use as required.

Warranty each Intelligent PIV LOFT has a FIVE Year Warranty as standard.*




Unit Setting

The unit setting is selected by the installer to suit the size, layout, thermal properties and moisture production in the home.

Unit SettingNormal
Airflow (Lis)
Heat Recovery
Airflow (L/s)
Max Filter Change
interval** (Years)
11717-34 (default 26)2.010
22121-42 (default 31)2.59
32525-50 (default 37)3.38
429 (default)29-58 (default 43)3.87
53333-66 (default 49)4.16
63737-70 (default 55)4.65.5
74141-70 (default 61)5.65
84545-70 (default 67)6.54.5




The unit will run in this mode for the vast majority of its operational time until the

unit’s integral temperature sensor switches it to Heat Recovery or Standby mode or the Override Boost mode (if connected via a suitable switch) is activated by the occupants.


The unit constantly monitors the incoming air’s temperature and moisture content. When the incoming air is below 10°C the unit checks its moisture content to see how dry it is as less drier air is needed to be supplied to the home to control internal humidity levels. The unit’s Normal airflow is reduced automatically in proportion to its

moisture content under this function, however, to ensure minimum ventilation rates are maintained, a minimum of 50% of Normal airflow is always provided. This unique control function can not only provide improved comfort levels for occupants, but can also significantly reduce the demand on their heating.

Heat Recovery

The unit will increase in speed when the loft temperature reaches the Heat Recovery trigger temperature to supply even more warmed air from the loft into the home.


The unit will essentially switch off when the loft temperature reaches the Standby trigger temperature to save energy and prevent undesirable warm air being introduced unnecessarily into the home e.g. during hot summer days. This function can be disabled if continuous running is required e.g. radon gas control.

Override Boost

The unit’s automatic controls can be overridden to operate the unit at its maximum airflow by means of a user switch hard wired to the relevant connections within the unit.

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