Condensation, damp and mould are all unwanted intruders in your home and Positive Input Ventilation is one way to help combat the issue. The right PIV unit type will help push clean air through your home and get rid of the old stale air. It’s this process that helps reduce the chances of mould and damp making an appearance.
Positive Input Ventilation can be installed in any home, but which type you choose will depend on the property you live in. Here ventilation experts reveal the different types of PIV units available on the market and which one will work best for your home.
Thomas Oldham
Thomas Oldham has spent the past four years using his expertise of working in the engineering and construction industry for over a decade to develop the UK Construction Blog - a leading online platform dedicated to empowering individuals and businesses in the construction industry.
PIV unit options
(PIV) Positive Input Ventilation units while performing the same task are available in different types. These are typically used in different property types to get the best performance. Here, Thomas Oldham, Co-Founder, UK Construction Blog gives a quick overview of the different options.
Loft-mounted units
The most common type, installed in the loft space to draw in fresh air from outside and filter it before distribution throughout the property.
Wall-mounted units
Designed for properties without lofts, such as flats. These are fitted directly to an external wall.
Heater PIV units
Include built-in heating elements that warm incoming air during colder months, preventing cold draughts.
Matthew Jenkins
Matthew Jenkins has worked as a self-employed tradesman in the domestic heating industry for over fifteen years. Matthew is a gas safe engineer specialising in heating and plumbing. He also works closely with MyJobQuote to provide expert knowledge to homeowners and tradespeople and has been featured in a range of established news outlets.
Matthew Jenkins, HVAC expert at MyJobQuote goes into more details, pointing out that loft units are the most used options. “Positive Input Ventilation (PIV) units are typically designed to be fitted in the loft, with the diffuser unit, which distributes the fresh air, mounted on the ceiling directly below.”
He adds, “This not only makes installation simple, but it allows the PIV unit to use the fresh air brought in from the roof vents. It also keeps clutter and noise to a minimum.”
While basic PIV units for lofts are a popular choice, heated options are not uncommon as Jenkins explains, “Many PIV systems have an integrated heater to warm the air before it distributes it, saving you from cold draughts in winter.”
He adds, “These also tend to have sensors that enable the heater to turn on and off automatically as the air temperature changes. This ensures the system runs efficiently.” More advanced PIV units can have extra features as Jenkins continues, “Some models also come with a hygrometer, to automatically adjust the airflow to match humidity levels.”
If you are thinking of investing in a PIV unit Jenkins says, “Basic PIV units cost around £200 to £300 but those with heaters, sensors and central control panels tend to cost a bit more. So, you’re likely to pay between £400 and £1200.”
If you in a flat or a space that doesn’t have available loft space, wall mounted PIV units are the obvious alternative as Jenkins shares, “If you live in a flat or don’t have a usable loft space, there are PIV units designed for fitting on a wall in a hallway or similar location.”
These work in a similar fashion to PIV loft units, but draw the air from the outside as Jenkins explains, “This type of PIV unit still needs to take fresh air from outside, so it’s best to position it on an external wall to reduce the amount of ducting you need.” He adds, “Wall-mounted PIV units cost between £150 and £500. Compact and quiet-running units with integrated heaters tend to be priced at the top end of this range.”
The Nuaire Drimaster is a basic loft mounted PIV unit that comes with its controls integrated into the main unit. This allows you to set the airflow throughout your home.
Vent-Axia Pure Air Home With Heater PIV
A loft mounted PIV unit that comes with a two-speed 500W heater to warm the air when needed. Adjustable legs help secure the unit and all fixings are included.
Nuaire Flatmaster Wall Fit PIV
A compact wall mounted PIV unit that is an alternative to loft based units. Multi-positional spigots allow for quick installation and only one external wall penetration.
How to look after PIV units
PIV units are generally pretty simple to look after and costs are minimal as Oldham shares, “One of the most significant advantages of PIV systems is their minimal maintenance requirements compared to dehumidifiers and air conditioners. They are fully autonomous systems requiring virtually no maintenance.”
The only maintenance is a regular service as Oldham continues, “Regular servicing involves filter replacements every three to five years, depending on installation location and environmental factors.”
And, the cost is negligible, “These filters typically cost £20-£40,” adding, “With service visits ranging from £80-£150 if professionally replaced.” Replacing a filter is a task that you can take on yourself, just remember to get the right filters for your PIV unit.
Jenkins adds, “Typically, if you live in an area with high levels of air pollution or humidity, it’s wise to get an annual service.”
Can I install a PIV unit myself?
Installing a PIV unit can be tackled on a DIY basis, but if you have never done it before there is a lot that can be missed. Ideally you want to call in a professional as Oldham shares, “Whilst PIV units can technically be installed on a DIY basis, professional installation is strongly recommended.”
He goes on to say, “This is because components need installation in hard-to-reach locations such as lofts, systems require connection to mains electricity, which must be done by competent installers.”
A poorly or incorrectly installed PIV unit will prevent a property from appreciating the full benefits. Jenkins shares why, “A PIV unit needs to be wired in by a qualified electrician and also need to meet building regulation requirements in terms of ventilation and fire safety. For instance, your PIV unit may need to include a fire damper.”
How much does it cost to install a PIV unit?
While you can install a PIV unit yourself, Oldham says, “PIV installation is best handled by qualified ventilation specialists, heating engineers or electricians with relevant experience.
Jenkins reveals how much you will have to pay for a professional installation, “It’s likely that you’ll pay between £300 and £1200 for your PIV unit, including the fan, filter and diffuser and additional materials like wiring. The labour should cost somewhere between £700 and £1000, depending on the complexity of the installation.”
He adds, “So, a professionally installed PIV system, including materials and labour, should be around £1000 to £2200.” But this can vary on location and the experience of the installer. As always, get a few quotes from local trades for a price for your particular installation.
And once the PIV is installed you’ll need to factor in running costs as Jenkins shares, “A basic PIV unit typically costs £10 to £15 a year to run but those with a heater do use a bit more electricity, so your annual running costs could be nearer £60 to £100. On top of this, there is the servicing and filter replacement."
He adds some final words, “However, this is still likely to be cheaper than running a dehumidifier on a daily basis.”
No-one wants condensation in the home and the right ventilation helps make sure its doesn’t take over and lead to mould and damp issues. Check out our building regulations Part F to see how regulations can affect a remodel and what your minimum house temperature should be.
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Steve Jenkins is a freelance content creator with over two decades of experience working in digital and print and was previously the DIY content editor for Homebuilding & Renovating.
He is a keen DIYer with over 20 years of experience in transforming and renovating the many homes he has lived in. He specialises in painting and decorating, but has a wide range of skills gleaned from working in the building trade for around 10 years and spending time at night school learning how to plaster and plumb.
He has fitted kitchens, tiled bathrooms and kitchens, laid many floors, built partition walls, plastered walls, plumbed in bathrooms, worked on loft conversions and much more. And when he's not sure how to tackle a DIY project he has a wide network of friends – including plumbers, gas engineers, tilers, carpenters, painters and decorators, electricians and builders – in the trade to call upon.
