Description

Conventional ventilation keeps a home sufficiently aired but has an energy cost. An option is to install a mechanical ventilation heat recovery system that ventilates a home while efficiently conserving energy.

In New Zealand homes, New Zealand Building Code clause G4 Ventilation specifies that adequate ventilation is required to be provided through a combination of natural means – with windows and openings – and mechanical ventilation. The most common pathway for compliance with G4 is natural ventilation, with supplementary extract ventilation in bathrooms, for example.

Scope

This article includes:

• Opening windows does the job
• Mechanical ventilation and heat recovery
• Case study in a 100 m² house
• Efficiency and airflow balance
• Optimise ducting length and insulation
• Homes often spot heated
• Spot heating causes efficiency to drop
• Getting the highest efficiency