Balanced Pressure Fresh Air Home Ventilation vs Positive Pressure Roof Air Ventilation

Old vs. new ventilation systems

There are two types of Ventilation systems available in New Zealand:

  1. Old ‘positive’ pressure roof cavity ventilation systems
  2. New Lossnay ‘balanced’ pressure fresh air heat recovery ventilation systems

Old ‘positive’ pressure
forced roof cavity ventilation

Air goes in and gets trapped.

These systems typically force air into the home from the attic space and specifically require gaps in the building structure (common in older homes) to facilitate air displacement. As these systems are not designed to recover heat energy to help pre-warm incoming air, colder incoming air will require more additional heating – adding to your power bill.

New Lossnay ‘balanced’ pressure
fresh air heat recovery ventilation

Air goes in and comes out.

Balanced ventilation mechanically removes stale air and replaces it with clean, fresh air at the same rate. It is also fitted with a heat exchanger that actively recovers heat energy from the outgoing stale indoor air to pre-warm incoming fresh air. As such, the need for additional heating of fresh air is reduced. This system is specifically designed for modern homes that are of more airtight construction.

Find out more information on Domestic Ventilation Systems from Codewords - Department of Building and Housing:
- Click here to download PDF (47KB)

Why is outside air so important?

Not all air is created equal. Lossnay specifically only draws fresh air from the outside, it does not draw air from the attic. The absence of significant air movement common in attics means the air is likely to be stale. In addition, build-up of dust, dirt and other contaminants such as mould, insect and rodent droppings makes this air much harder to clean through filtration before it is distributed through your home. This is why the Lossnay system specifically utilizes direct fresh air instead.

To learn more about the difference between Positive Pressure and Balanced Pressure Ventilation Systems Beacon Pathways have put together the following fact sheet.

Fresh Air Home Ventilation

Positive Pressure vs Balanced Systems