Ventilation Systems
New Zealand houses have become more airtight since the early 1970s as aluminium joinery has replaced wooden windows, and concrete slabs replace wooden floorboards. This has improved energy efficiency when it comes to heating our homes, but the trade-off has been a reduction in passive ventilation which typically equates to staler air and higher levels of moisture and condensation.
This means that ventilation systems are now more important than ever, with a mix of passive and mechanical options generally delivering the best outcome.
The team at AVS have extensive experience in designing, installing and maintaining all types of ventilation systems. We’ll work with you to find the best solution for your new build or to retrofit into your current home.
UNDERSTANDING DIFFERENT TYPES OF VENTILATION
Ventilation terminology can be a little confusing so we’ve explained some of the most common systems below.
Passive Ventilation
The term passive ventilation refers to non-mechanical methods of bringing fresh air into your home and letting stale air out. Common methods of passive ventilation include doors, windows, vents and louvres.
Balanced Pressure Heat Recovery Systems
Balanced pressure ventilation systems have two fans for two different air streams:
One supplies fresh outdoor air into the house through ceiling vents
The exhaust fan extracts an equal volume of air from inside the house and discharges it outside.
Some of the heat from the exhaust air recirculates into the incoming air via a heat exchange unit which is usually located in the roof cavity.
Some products include additional features that use the heat generated in the roof cavity on a sunny winter day, or to avoid the incoming air being warmed by the exhaust air during summer nights.
Balanced pressure heat recovery ventilation systems are particularly suitable for modern homes in colder areas that are already well heated and reasonably air tight.
Positive Pressure Ventilation Systems
Positive pressure ventilation systems force filtered air from your roof space into the house via ceiling vents. Most systems have a single fan that forces air through ducting into multiple ceiling vents. Ductless systems consist of one or more self-contained ceiling vents that have their own built-in fans.
Positive pressure ventilation systems are widely used type in New Zealand and are generally associated with reducing moisture and condensation levels within the home.
Roof space Ventilation Systems
Roof space ventilation systems typically use passive (non-mechanical) devices to provide continuous, unimpeded airflow into the roof cavity of your home.
Roof space ventilation reduces the risk of potential problems such as condensation build-up which can cause building materials such as building underlays to fail. High levels of condensation can also lead to mould growth which has been associated with New Zealand’s high level of asthma and respiratory diseases.
