Passive design is a crucial part of sustainability and ensuring better energy efficiency and thermal comfort in homes.

The concept of the Passive House (Passivhaus) originated in Germany in 1991. It is a set of design principles that have been highly influential globally.

The aim of passive design is to create sustainable houses which require very little energy to create comfortable dwellings, with excellent ventilation and air quality.

Thermotek Windows & Doors - Passive House Design

What is a Passive House?

In passive design, the building envelope does most of the work to achieve thermal comfort, without active input from energy-consuming devices such as air conditioners and heaters.

Passive House standards are performance-based, rather than having set guidelines as to materials that should be used.

The Passivhaus Institut oversees a global certification scheme that assesses these performance standards.

Let the building do the work - not the appliances.

5 Key Design Principles of a Passive House

1. Airtightness

Passive Houses are defined by an airtight building envelope.

In practice, this means that there is a very limited amount of gaps and cracks, reducing drafts and giving you control over the internal environment. Removing drafts ensures optimised thermal comfort.

Thermotek Windows & Doors - Passive House Design

2. Thermal Insulation

Excellent insulation provides a sufficient layer between the heated or cooled inside environment and the outdoors. This will reduce radiant heat gain in summer and conductive heat loss in winter.

This improves comfort and reduces condensation by minimising cold surfaces; mitigating the risk of dampness and mould.

At Thermotek, we glue the window sashes to the pane. This ensures that the window has excellent insulation and enhances its stability. Windows no longer need reinforcing with steel, which is more favourable for thermal comfort.

3. Mechanical Ventilation Heat Recovery (MVHR)

A Mechanical Heat Recovery Ventilation (MVHR) system effectively salvages heated and cooled air that would otherwise be wasted while also filtering the air that’s coming into the building. This means cleaner air plus a lower risk of condensation – without needing to open your windows!

It brings in fresh outdoor air without letting heat escape, continuously removing unwanted moisture and pollutants and providing improved filtered air.

4. Thermal Bridge Free Construction

‘Thermal Bridges’ are areas that cause increased heat consumption and increased condensation risk.

The insulation needs to be a good thickness and continuous. This means keeping interruptions to the insulation to a minimum. If penetrations or cut throughs must be made for construction, it should be done with materials that are less conductive, like timber. Or thermal breaks can be used, whereby a material that doesn’t conduct heat well separates two conductive materials (like metal).

Wall wrapping is one example of a commonly used insulation barrier. However, unless it is properly wrapped, sealed and incorporated around joints, joins and windows it can easily be ineffective in areas.

Thermotek Windows & Doors - Passive House Design

5. High-Performance Windows

Windows should have good levels of insulation, prioritising low-emissivity double or triple glazing with thermally broken or non-metal frames. The size of the windows should also be consistent with the building envelope, to allow for the right amount of solar radiation in summer and winter.

Windows should have rubber seals for airtightness, plus frames should either have a thermal break or be made from a non-conductive material like uPVC.

Thermotek windows are engineered in Germany and manufactured in Australia, crafted for outstanding thermal performance and energy efficiency.

The uPVC used has high thermal insulation properties, while the IGUs (insulated glass units) use standard Low-E glazing with argon gas.

Our frames consist of various fusion welded air chambers. These give a superior seal which increases insulation, and the dual TPE (thermoplastic elastomer) seals further enhance thermal performance.

The gap between the two panes in Thermotek windows is the main source of insulation, which slows down thermal transfer by conduction. The systems slow down air circulation to reduce the amount of heat lost in winter and gained in summer.

Thermotek windows keep your home’s temperature more stable, and cuts down the number of times your heating/cooling system must switch on and off.

Thermotek Windows & Doors - Passive House Design

Passive House Design: Frequently Asked Questions (FAQs)

What are the key benefits of Passive House design?

Passive House design principles are positive for both people and the planet, using the building envelope to increase thermal comfort without energy consumption. It:

  • Creates durable, resilient buildings that reduce heating energy use by as much as 90%.  
  • Decreases operational carbon emissions.  
  • Cost-effective and predictable energy performance gains.  
  • Healthy, comfortable, calm, and quiet interior environments, full of clean, filtered fresh air. 

What types of buildings can be created with Passive Design principles?

Passive buildings include houses, high-rise office towers, apartments, schools, or any building type. Passive House design improves energy efficiency in new construction as well as retrofits. There are generally three building performance targets:  

  • Very low thermal energy use. 
  • Very low total energy use. 
  • Superior air tightness.

How does Passive Design help achieve Zero Carbon Buildings?

Passive design optimises both building performance and value for zero-carbon buildings by:  

  1. Maximising energy efficiency. 
  2. Minimising the embodied or upfront carbon emitted from construction. 
  3. Electrifying everything.  
  4. Powering it all with clean energy.  

Can Passive Houses make you healthier?

There are many benefits to Passive House design, including health benefits. The U.S. EPA estimates that 90% of our lives take place indoors. Better internal air quality can significantly improve health, with reduced pollutants and CO2 levels.

Passive design promotes clean, oxygen-rich air when inside thanks to the ventilation systems. The engineering of passive houses also reduces condensation, mitigating dangerous mould and mildew.

Why are Passive Houses more comfortable dwellings?

Reasons for superior comfort levels include: 

  • Nice even surface temperatures thanks to thermal bridge-free building assemblies.  
  • Super-insulation.  
  • High-performance windows.  
  • Minimal stratification of interior air temperatures thanks to those even surface temperatures. 

The smart design of both solar gain and shading, etc. 

Are Passive Houses quiet?

Passive homes are insulated against noise thanks to their robust high-performance walls, windows, and doors. They also reduce sound transmission from outside.

You will notice the significant difference in ambient noise as soon as you walk inside a passive house.

How do Passive Design principles help meet NCC requirements?

The recent updates to the National Construction Code (NCC) put the focus squarely on energy efficiency. There were two key changes to residential works, including apartment buildings:

  1. Thermal performance requirements were raised to 7 stars under the Nationwide House Energy Rating Scheme (NatHERS).

  2. A new Whole-of-Home Rating must be met by new homes. This applies to heating and cooling, hot water systems, lighting, swimming pool and spa pumps, windows and doors. Renewable and sustainable energy systems, such as solar panels, aren’t mandatory but can be installed to keep a home’s energy under budget.

Passive house design principles help achieve optimal thermal performance, plus also reduce the need for appliances and heating/cooling systems.

Thermotek Windows & Doors - Passive House Design

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