wall covered in mould next to a condensated window

What fan is best for condensation and mould problems?

5 min read

Before we get stuck into the nitty-gritty, for those of you looking for a quick answer, here are a couple of links to some top extractor fans to help reduce condensation and mould - for those of you looking for more answers regarding PIV, read on!

Envirovent LV2-EVL-H PIV Unit
Vent Axia PureAir 479091 PIV Unit with Heater
Tornado Silent dMEV with Humidistat & Timer
Tornado ST100HT Intermittent fan with Humidistat & Timer

At EFW, we are often asked what the best fan is for mould and condensation problems.  First, let’s just take a moment to understand what causes these common problems in the home. If the humidity in your home is too high when warm air hits cold surfaces, water droplets can form on walls and windows. Over time these water droplets can develop into mould. 

Mould of course isn’t just an unsightly by-product of condensation but can be dangerous when mould spores are released, particularly in the case of people suffering respiratory diseases.

The great news is, it is possible to prevent condensation through the use of correct ventilation, by removing this excess humidity or moisture in your home. If we consider that daily activities in the home, such as drying clothes, washing and showering, cooking, or exercising, can generate up to 10 litres of moisture per day, we can see how important it is to have a ventilation strategy.  Ironically, the drive to over-insulate our homes in recent years has probably exacerbated the problem of poor air quality further.  Thankfully, there is a range of options available to tackle condensation and humidity problems. Here we take a look at the simple to install but effective PIV units.

What is Positive Input Ventilation (PIV)?

Positive Input Ventilation (PIV) pushes out that stale & humid air and replaces it with fresher, drier, gently filtered air into the home. By removing the moisture in the home, we are effectively attacking the very source of what causes mould. Condensation can no longer settle on those colder surfaces, and mould cannot grow.  Our range of PIV systems provides the ideal solution for all property types, whether you live in a flat or house. For the homeowner, you can be assured of improved air quality and reduced maintenance problems caused by condensation and mould. The unobtrusive units, low running costs, and very quiet operation make them a simple solution to a common problem in the home.  For the landlord, the PIV units offer reduced maintenance and call-outs, whilst offering the perfect solution for ongoing condensation problems.  For the installing contractor, the Smart Sense technology makes for a fast install and setup, with the adjustable legs suiting a variety of tricky install situations.  For the ultimate solution to damp and mould problems, we recommend pairing a PIV unit with a continuous running fan. 

 

Is there a range of simple to install PIV units?

The great news is that several manufacturers now offer a range of PIV units, which are easy to install and set up. Depending on the property type, you can choose between loft-mounted and wall-mounted standalone units.  Some units also come with a heater, to ensure the clean air is gently warmed before entering the main living spaces.  We take a look at the ranges on offer below.

National Ventilation Monsoon Energysaver PIV Unit

National Ventilation’s Monsoon PPS/LH fan is simple to fit, with a choice of the supplied hanging or base mounting kits.  Similar to the Vent-Axia range, the unit is designed to be easily hidden away in the loft space, with only the diffuser installed in the hallway.  Quick setup is covered with a handy house size selector, with the unit also offering a low energy trickle function and higher output boost function.  A 5-year guarantee gives peace of mind for a long trouble-free operation.

National Ventilation Energysavr Wall Positive System

For those houses where loft installation is not possible, Natvent also offers a lightweight and convenient box mounted option with running power as low as 4 Watts.  The PPS/W/H offers 4 mounting positions to fit into the tightest of places.  Control is made easy via an easy to read display.

Vent-Axia Pure Air Home

For a loft-mounted PIV unit in the home, the Pure Air Home (479090) from Vent-Axia is the ideal solution. The unit comes equipped with adjustable speed control, to suit installations up to 150m2. Designed to be mounted in the loft, the unit will switch off in the summer, to prevent further warm air from being sent back into the property. 

In the winter months, the energy-efficient heater-equipped model (479091) will gently warm the air being sent into the home.  Finally, to complete the Pure Air Home range, the 3-storey compliant model (479092) is supplied with a Fire Damper relay to a fire alarm, which will cut off in the event of a fire - please contact us directly if you are interested in ordering this model.

All units benefit from the following features:

  • Anti-vibration mounting kit
  • Adjustable from 11 litres per second to 60 litres per second dependent on size of home
  • Super low running costs with lo-carbon motor technology
  • Super low sound levels from just 9dB(A) means the unit will hardly be noticed when installed
  • Unit supplied with flex duct, ceiling diffuser, and G4 5-year maintenance-free filters
  • 5-year standard warranty on all models

Vent-Axia Pozidry Pro Range

The Pozidry pro range includes all of the fantastic features of the Pure Air Home range, but with the added Smart Sense data logger. The unit cleverly records accurate running data for each of its speeds, and the number of days the unit has been used. Further, the data logger will even let you know when the filter is due for replacement.

Vent-Axia Pozidry Compact Pro

To complete the Vent-Axia range, the compact pro unit is ideal for wall mounting in properties that do not benefit from having a loft. Multiple inlet and outlet positions allow for the unit to always be installed in the optimum mounting position.

Should I also install a continuous running fan?

When you think of a PIV unit, the air is effectively being pulled into the living area from the loft space, or filtered and re-circulated within the space in the case of the wall units.  This is great and for many presents an excellent solution to damp and mould conditions.  However, we can take air movement a step further and actively pull any stale and humid air out of the property, by using a continuous running fan.  This is especially important if your home has been designed around an air-tight principal or if you need the PIV to target specific problem areas rather than a whole house solution.  Our recommendation is the Tornado ST100DMEVHT Silent dMEV Continuous Running Extractor Fan, a feature packed fan, with a fully automatic continuous ventilation mode. The fan can also be set up as a standard intermittent fan, by simply lifting the cover plate and changing the desired mode. Continuous running fans offer several benefits over conventional extractor fans, due to their usually near silent constant volume, and continuous extraction. For older buildings, pairing PIV with intermittent extractor fans such as the Silent Tornado range will help to maximise the potential PIV effectiveness across the whole home.