Positive Input Ventilation (PIV) Questions answered

Positive Input Ventilation (PIV) Questions answered


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Video Transcript:

Hello - welcome to Electric World TV.

In this episode of Fansplaining we will be answering some of the most common questions asked about PIV or Positive Input Ventilation.

For simplicity, we have taken eight of the top questions asked on Google and if you would like to look at our available range of PIV units, please follow the link in the description below.

Let’s begin:

Question Number 1

What is positive ventilation?

Positive input ventilation draws filtered air from the loft space and gently pushes the air through your home forcing stale air out of the natural gaps in the fabric of the building or through trickle vents.

PIV units filter the incoming air, removes any particles such as pollen, and then gently releases the fresh air through a central vent into your home at a constant rate to create and supply positive air pressure, resulting in the air in the property being continually diluted, displaced and replaced, creating a healthier indoor air quality.

Question number 2

Is a PIV system worth it?

If you are suffering from damp and mould issues in your property, there are various ventilation options you can look at.

But most of these can be rather invasive to install, with long ducting runs that will need to be placed within the building structure to reach multiple rooms within the building.

PIV systems are a simple and effective solution to household damp and mould problems and are the least invasive to install, requiring only a single ceiling grille and electrical wiring in your loft space.

This makes PIV systems the best option to install into an existing building with minimal structural interference. Definitely worth it!

Question number 3

Will a PIV stop condensation?

Yes - this is predominantly what PIV systems are designed for.

By displacing humidity in the home and replacing the atmosphere with warm, dry air, condensation will be re-evaporated and forced out of the building.

Over time, the continual process of the PIV will remove humidity before it has a chance to condense and settle in the property.

Question number 4

Do PIV units run all the time?

They do - but many will have a summer bypass cut-off to stop hot air in your loft in summer months from being forced into the habitable part of the building.

Most units have three automatic operating states:

On with heater element turned on to warm incoming air in winter months,

On with heater element turned off in warmer months and Off completely in hot summer months when the loft air exceeds a set temperature.

Question number 5

Does PIV make your house cold?

The simple answer is no but it depends on the model of PIV unit you install.

Many PIV systems include a heating element to warm the air before introducing it into the property.

These heating elements have a summer bypass function so you won’t have hot air introduced when the ambient temperature is high.

But not all PIV units have this heating option.

As the air is being supplied from your loft space, the temperature of the air being introduced from a non-heated PIV unit will depend on the temperature of the loft air.

The majority of the PIV systems purchased from us are units incorporating the heating element and we would recommend choosing this option.

Question number 6

Should PIV windows be open or closed?

Ideally, you will want to keep windows closed.

Open windows allow cold, moisture-filled air to enter buildings which will have a detrimental effect on the desired effect of eliminating damp issues.

They will also create a hot/cold air barrier that will condense the exiting moisture faster at the open windows causing a higher amount of condensation on the glass. 

Question number 7

Do I need trickle vents with PIV?

It depends!

If you are installing a PIV into an older property, there will probably be enough gaps in the fabric of the building to allow the air to be forced out of the building.

However, if you are fitting a PIV into a more modern building, many of these builds will have been designed to minimise air loss to help maintain the energy efficiency of the building.

The downside to this style of building design is that it traps stale and humid air in the building and a PIV unit will struggle to force this air out.

In these cases passive vents can be installed but a more efficient option is to install dMEV units to replace bathroom, utility room and kitchen fans.

The trickle extraction from these will control the extraction from the house and help to minimise any returning cold air through unregulated passive trickle vents.

Check out the link in the description below to our video on dMEV units for more information.

Question number 8

Can an electrician install a PIV unit?

Absolutely - in fact we would always recommend a qualified electrician install any form of mechanical ventilation, whether it is extraction or positive pressure ventilation.