Passive House Builder

Passive Homes

Certified Passive Home Builders in Melbourne

As specialist passive home builders, we have an extensive understanding of the technical building methods and different cosmetic finishes required to build a high performance, energy efficient and sustainable home. 

What is a Passive House?

It is a safe, comfortable, and hygienic environment for its occupants.

Seal EnA Passive House requires very little heating and cooling to keep it in a comfortable temperature range throughout the year. In technical terms, this equates to less than 15kWh of energy for heating and cooling per square metre of floor space per year.

To be certified as a Passive House a building must meet stringent standards for airtightness, thermal insulation, heat recovery ventilation, high performance glazing and thermal bridge-free design.

The building methods and products used in a Passive House are extremely durable, thus full life cycle costs to build, maintain, heat, and cool it are very low compared to a standard building.

Can a renovation be carried out to Passive House standards?

Yes, but because of the challenges and costs involved in retrofitting Passive House products and building methods to an existing building, an alternative EnerPhit standard has been developed for this purpose. EnerPhit certification has slightly less stringent requirements than Passive House certification.

Some home extension projects achieve dual certification. This means the existing portion of the dwelling achieves EnerPhit standard, and the new part of the dwelling is built to Passive House standard.

Finally, an energy-efficient home can be designed using Passive House building principles without having to meet all of the strict thresholds for Passive House or EnerPhit certification standards. We refer to these homes as High Performance buildings.

The 5 Fundamentals of Passive House building

  1. Airtightness

This is extremely important for Passive House design because the mechanical heat recovery ventilation system – described below – can only work effectively within an airtight building envelope.

Airtightness is measured during the building process by pressurising the house using a blower door fan. The amount of air that leaks through the building fabric is measured over the next few minutes. With this information, the air changes per hour (ACH) number is calculated. A Passive House Certified house must have an ACH number of less than 0.6, and an EnerPhit Certified house must have an ACH number of less than 1.0.

  1. Thermal Insulation
    • Roofs, walls, and floors must be insulated to ensure heat does not move into or out of the building easily.
    • The layers of building materials, weather-resistant barriers, airtightness membranes, and thermal insulation are commonly known as wall and roof build-ups, and these vary according to the climate zone the Passive House is built in. For example, a Passive House external wall in a cold climate such as Sweden might be over 250mm thick, whereas a Passive House in Melbourne could meet Passive House requirements with a far thinner external wall.
  2. Mechanical heat recovery ventilation
    • Passive Houses must be fitted with a heat recovery mechanical ventilation unit. This unit:
      • Extracts air from certain areas of the dwelling, passing the extracted air through a heat exchanger then purging the used air
      • Draws in fresh air from outside, filtering it to remove dust and pollen and condensing out excess moisture, then passing this air through the heat exchanger to condition it to the desired temperature.
    • These units are extremely efficient (more than 75%) and use less power than a halogen lightbulb.
  3. High performance windows

Passive House windows utilise low thermal conductivity frame and glazing materials and are installed to ensure they do not create thermal bridges with the outside.

  1. Thermal bridge-free construction

A thermal bridge is a penetration through the thermal envelope of the building which facilitates thermal energy transfer through the building fabric resulting in undesirable gain or loss of heat. Passive House building requires that thermal bridges are minimised and eliminated where possible.

To build a Passive House do I have to use specific products?

No! Passive House is an extremely adaptable framework based on the measurable performance of a building, not the materials from which it is made. For example, some Passive Houses are built on a concrete slab. However, many instead utilise lightweight timber construction.

At Northern Building and Carpentry, we prefer to use timber due to its low embodied energy, sustainability, end-of-life potential (ability to be efficiently recycled), and ease of installation.

Why do we promote Passive Houses?

We believe the Australian building market needs better homes.

We are transitioning to a minimum standard of High Performance building by late 2023.

We believe it is the responsibility of everyone connected to the Australian building industry, including manufacturers, builders, and clients, to make ethical and sustainable decisions and build in a way that assists the health, amenity and enjoyment of occupants

Northern Building and Carpentry are certified Passive House tradespeople

Why you should consider Passive House for your build

Choosing Passive House, EnerPhit or High Performance building design will make your home comfortable, healthy and cost-efficient all year round

Contact us to discuss how we can use Passive House, EnerPhit and High-Performance building to improve your existing home or build you a new one.