Are you familiar with Positive Input Ventilation Systems? Likely, you won't know much about them unless you've had one fitted or explored the idea of getting one.
It could be that you've searched online using a term like, PIV unit making house cold, implying that you've already got one fitted and you're having problems. Either way, we need to provide the right information to help everyone, and that means keeping things simple.
Most people don't realise that the PIV unit has been around since the 1970s when they were introduced to the market by Nuaire, whose Drimaster and Flatmaster models are still going strong today! As experts in Positive Input Ventilation (PIV) unit installation, it's easy for the PIV Team to forget that not everyone knows about these handy gadgets, so we need to address that here.
The basic idea behind these ingenious systems is to reduce condensation, which is a major contributor to damp issues and black mould growth. For several reasons, which we'll look into later, these problems are getting worse, so more consumers are seeking solutions. The PIV unit is one of the solutions that are being considered by thousands of homeowners.
However, most people still don't know much about them, leading to concerns and questions about their effectiveness.
In this blog, we are tackling a question that gets asked all the time, and we'll do our best to provide a coherent and comprehensive answer.
So, let's get right into it and ask...
The easy answer is no; PIV systems don't make your house cold - on the whole.
But, as always, it's not as easy as that. Under some circumstances, a Positive input ventilation system can make a house feel cold!
To get to the truth, we're going to have to dig deeper into the subject to uncover all the facts.
The best place to start is with an overview of how PIV systems work.
Positive Input Ventilation (PIV) is a mechanical ventilation system that supplies fresh, filtered air into a property at a continuous rate throughout. It works by drawing fresh air from outside through an intake vent, filtering it, and then gently diffusing it at ceiling level. This creates a positive pressure* within the home that forces stale, humid air pollutants out through natural leakage gaps found in every UK property, both old and new.
Explore further: What Is A PIV Unit
*as opposed to extractor fans, which produce negative pressure
Here's a simplified explanation of how Positive Input Ventilation works:
PIV units are an effective and energy-efficient way to ventilate homes and prevent condensation and mould growth. They are particularly beneficial for older homes that may not have adequate natural ventilation.
It's a marvellous invention that has improved airflow in millions of homes in the UK, eliminating condensation and reducing mould problems.
So, why does it sometimes make houses feel cold?
Using our knowledge of PIV systems, we've put together this list of potential reasons:
PIV systems, known for their effective ventilation, draw in fresh air from the outdoors. During the winter months, this incoming air can be notably chillier than the indoor atmosphere. As it courses through the house, it has the potential to cause a perceptible dip in temperature, especially in regions lacking adequate insulation or plagued by drafts.
PIV systems significantly boost a home's overall ventilation, resulting in a higher rate of air exchange between the indoors and outdoors. While this serves the purpose of purging stale air and mitigating condensation, it also introduces a greater influx of cold air into the interior spaces.
One of the advantages of PIV systems lies in their capacity to reduce humidity levels* within a residence. Paradoxically, this reduction in moisture levels can contribute to an air ambiance that feels colder. Dry air, with its lower moisture content, is more proficient at sapping heat from the body compared to humid air.
*Oddly enough, it's warm air that causes condensation problems, as it carries moisture that condenses on cold surfaces!
Homes equipped with PIV systems may encounter issues if their heating systems are inadequately sized or not properly maintained. Such systems might struggle to cope with the escalated ventilation facilitated by the PIV, resulting in a sensation of coldness, particularly in zones afflicted by poor airflow or uneven heat distribution.
A peculiar circumstance arises in some homes where the loft area (where most PIV units) registers significantly lower temperatures than the inhabited living spaces. As we know, warm air rises, so loft spaces often have a higher temperature. However, during winter months, the temperature drops, particularly if there is inadequate loft insulation.
If the PIV unit draws air directly from this chilled loft space, it ushers a substantial volume of cold air into the living areas, exacerbating the coldness within.
Find out more: How Does A PIV Unit Work
Now we know what the problem might be, how do we fix it?
Again, using our expertise, we can offer some possible solutions:
Certain PIV units come equipped with built-in heaters that temper the incoming air, preventing it from being excessively cold. This feature proves invaluable in maintaining a comfortable indoor environment, especially during the winter season when external air tends to be chillier - nobody wants a PIV unit continually pumping cold air through the house in the middle of January!
In summer, an automatic switch stops hot air from being pumped back into the system.
Customising the ventilation rate of your PIV unit minimises the constant flow of cold air during the cooler months. Using a timer or a dedicated controller allows you the flexibility to set varying ventilation rates for different periods throughout the day, effectively managing the balance between air exchange and indoor temperature regulation.
Boosting your home's insulation by sealing air leaks and drafts is an excellent way of maintaining warmth within your living space. This proactive approach not only keeps your home cosier but also cuts the volume of cold air introduced by your PIV unit, contributing to a more comfortable indoor climate.
Even so, you still need some gaps to allow airflow. Modern passive housing is all very well with its sealed-up interior, but these homes often fail when it comes to air quality as it isn't allowed to flow freely.
Your heating system has to be the right size for the space and must be well-maintained to cope with the challenges posed by increased airflow. It may be time for an upgrade!
If PIV-induced coldness continues to bring discomfort, it might be wise to explore alternative ventilation strategies. This includes simple measures such as natural ventilation, opening windows and doors, or using an extractor fan to extract stale air.
You could also fit a mechanical ventilation heat recovery system that draws heat from the outgoing air, although this will incur extra costs as it requires extensive ducting throughout the entire home.
Finally, in this section, was your PIV fitted correctly? Professional installation is highly recommended to get the best from your PIV system!
At PIV Team, we stand by our claims that positive ventilation is a brilliant tool for reduced condensation and humidity levels in the home. It improves energy efficiency and helps lower your energy bills, as it uses low-wattage for pulling air through the system.
PIV units also make much less noise than other methods, like air conditioners and extractor fans, and they improve ventilation in your home without the high running costs.
They can work very well, but they aren't suited to all types of properties.
Here's a quick guide to show which properties have a higher risk of failing or causing more problems than they fix:
Before getting a PIV system fitted, it's essential to get a qualified expert to assess your property.
We are proud to offer cost-effective solutions at PIV Team, and we would never advise a customer to install PIV if we considered it a bad investment. We always recommend the best method based on your circumstances and your budget.
So, if your PIV unit is making your house cold or you want more advice, remember that the PIV Team has the expertise to help you.
Explore: PIV Unit Installation Cost
