Prevent Condensation and Mould with a PIV unit

Many properties suffer from condensation and mould problems every year in the United Kingdom, especially during periods of cold weather.

Sometimes occupants can make adjustments to their daily routines to help reduce the amount of excess moisture production in order to prevent condensation, but often improvements to ventilation are required.

Many homes have carried out draught proofing, which while keeping heat in, also traps moisture in the property, this can often lead to condensation and mould problems.

Rentokil Property Care are experts in condensation control and damp proofing, and have decades of experience working with homeowners, social housing providers and our commercial clients.

The first step is always to carry out a damp survey in order to fully understand the problem at hand, in order to identify the root cause of the damp problem. Once the problem has been confirmed as condensation, our Rentokil Property Care surveyor will provide you with expert advice and solutions, including the installation of a positive input ventilation (PIV) unit, if required.

Positive Input Ventilation (PIV) is a system of ventilation that provides fresh, filtered air from outside and pushes it through the whole property, displacing stale and humid air. This in turn prevents condensation and mould by increasing air flow.

It works as the fan unit, typically located in a loft space, continuously supplies filtered air into the property, creating a slight positive pressure which forces out the moisture laden air trapped inside.

Yes, positive input ventilation systems are an excellent way to increase ventilation in a property, and will help prevent condensation and mould problems.

The fresh and filtered air that is introduced into the property works by creating positive pressure which then forces the moisture laden air out of the building. This means that the moisture vapour is unable to condense on cold surfaces in the property, preventing condensation and the conditions for mould to form.

The PIV unit is placed centrally, either in the landing ceiling or in a central hallway, and is therefore able to provide air flow through the whole property.

All properties will have natural gaps under floors, doors, window sashes, while trickle vents and airbricks provide further outlets for the stale air to be removed from the property. As stale and humid air is replaced, not only does it help prevent condensation but it also provides a much more healthy environment for occupants of the property.

While PIV units will help remove humid air from the internal atmosphere, occupants should always try to reduce moisture production where possible, especially when cooking and washing.

Yes, a positive input ventilation unit is a much better option for removing condensation from a property. A PIV unit can provide constant improvements to ventilation and air flow and is able to force humid air out of the property through positive pressure.

This means it can solve a condensation problem in multiple rooms from the central point, including the rooms most likely to be where moisture is produced. A dehumidifier will only remove moisture from one position, limiting its impact throughout the property. Dehumidifiers will stop working once the water tray is full, which can limit their ability to provide an effective solution to the problem.

A PIV unit is seen as a long term solution to the problem, while a dehumidifier will only provide a short term fix, rather than addressing the root cause of the problem - a lack of ventilation and air flow. PIV systems also tend to be more energy efficient, meaning they’re much more cost effective for condensation throughout a property. PIV units are also much quieter than a dehumidifier.

There are two primary types of PIV units: loft mounted and wall mounted. While variations exist these are the two most effective ways to increase ventilation in a property.

The main benefits of installing positive input ventilation is the improvements to the internal environment of a property, by removing stale and humid air, and in doing so, diluting the humid air and in doing so, dust mite allergens and other volatile organic compounds from cleaning products, aerosols and scented candles.

• Alleviates allergies and conditions that can impact people with respiratory problems and asthma
• Prevents condensation and black mould forming
• Removes stale air, pollutants and odors
• Automatic and continuous so minimal monitoring is required
• Windows can be kept closed as ventilation is provided by the PIV unit, meaning reduced heat loss during winter
• Quiet running, sound pressure is less than 15dB
• Low power consumption rate, as low as 6 watts
• Low maintenance
• Typically non disruptive installation
• Integral pre-heater to temper incoming air
• Integral hours run meter to monitor usage

Rentokil Property Care have been working in the property preservation industry for decades, and we pride ourselves on providing the highest quality solutions based on findings from a damp survey from a qualified surveyor.

This means before we install a PIV unit, we will first inspect your property to understand the dynamics of the damp problem and the root cause.

Once our CSRT or CSTDB qualified surveyor has provided you with a survey report outlining their findings, and you wish to proceed with the installation of a PIV unit, a trained technician will install the system to the specification detailed in the report.

The installation process is usually straightforward, often non-disruptive and relatively quick. The technician will need access to the loft space, and will make sure there is appropriate ventilation in this space for the unit to work as intended.

Yes, a PIV unit will help reduce condensation - a type of damp - and mould growth associated with condensation. A PIV unit will not stop other forms of damp, such as rising damp or penetrating damp, making it important to first use a professional surveyor who can accurately identify the source of the damp problem.

PIV units are one of the most effective ways to prevent condensation, especially in properties that suffer from a lack of air circulation throughout the property.

PIV units can come with built in heating, which can temper air during cold periods. As a PIV draws in air, it will mix with the temperate air inside the property, and be warmed by this. When a property has the correct balance of heating, insulation and ventilation the heat loss caused by a PIV unit should therefore be minimal.

Rentokil Property Care surveyors will be able to provide guidance and recommendations when carrying out a damp survey of your property.

No, PIV units are not expensive to run, with annual costs as little as a few pounds, while providing real and meaningful results to combat condensation.

PIV units benefit from solar gain in the loft space, while warm trapped air will mix with the newly introduced air flow, redistributing heat throughout the property. The long term benefits of PIVs means that you may prevent costly repairs by reducing condensation and the associated effects.

Rentokil Property Care has been working in peoples homes and businesses for over 70 years, correctly identifying property issues and providing long term solutions.

We are experts in property preservation, and can provide you with personalised advice for the condensation problem affecting your property. As part of our treatment plan we can provide expert ventilation improvements.