Positive Input Ventilation (PIV) systems are a type of ventilation system that is designed to provide a continuous supply of fresh air into a building which in turn can helping to improve indoor air quality and reduce the risk of moisture-related problems such as mould and mildew.
There are two types of PPU/PIV widely available. Loft units for properties with a pitched roof, and wall units for properties with no pitched roof, such as flats and apartments or flat roofed houses.
We have put together a list of frequently asked questions about the Positive Input Ventilation Systems to assist you with your before and after care queries. These questions are based on real life questions we have had from our customers.
The PIV unit does not extract, it creates pressure in the property which forces the stale humid air out through adventitious ventilation points. Every property has natural leakage points for air to escape from in the home; such as letter boxes, key holes, trickle vents in windows, cat flaps, gaps and cracks around doors, windows and floors.
The device is not a dehumidifier, and as such there is no drainage cycle involved. The system creates airflow through the property similar to natural ventilation. This means the humidity is reduced by replacing the stale humid air with fresh air, thus reducing the humidity levels and dewpoint within the property.
The PIV unit is very cheap to run, costing a fraction of the running costs of a dehumidifier which is essentially a freezer for air.
A PPU/PIV unit running cost varies depending on temperature outside (time of year) and what level the thermostat is set at. As a rule of thumb, a modern efficient unit with a 400-watt element that is correctly set up will cost around £35 per year to run, however as fuel prices are set to rise the figure may well increase.
The PIV units are whisper quiet, they do create a minor air movement noise but it is very low and blends into the background, not at all an aggravating sound.
The filters are recommended to be changed every five years by the manufacturer. we have supplied thousands of these units and in our experience this is fairly accurate, unless you live near a main road or a dusty farmers field when the lifespan can decrease.
We have customers who have simply washed the filters and put them back (they are cloth) rather than pay for new ones which are currently around £35 for a pair.
PIV / PPU units start to work immediately and will over a short period of time reduce the moisture levels in your furniture and furnishings. The difference can usually be felt straight away.
Yes, to ensure you get maximum benefit and to prevent any build up of excess moisture in the air, the unit should run continuously all year round.
Yes, to ensure you get maximum benefit and to prevent any build up of excess moisture in the air, the unit should run continuously (not turned off) all year round.
No, there is no app to control the unit. All of the required settings are done at the installation stage by our qualified team of specialists.
This is normal. During summer months, should the loft exceed 27°C the PIV loft unit will enter ‘Stand-by’ mode in order stop the circulation of warm air allowing for a more comfortable living environment. Heated PIV loft units automatically turn on the heater to boost air temperature during colder months.
We are Damp Proofing Specialists covering all areas of the North East of England, Newcastle, Tyne & Wear, Northumberland, Durham and beyond. Areas we cover include (but are not limited to) are:
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