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Passive House 101 Part 4

28 September 2023
Now the main living area, with views to the Brindabellas, this room used to be used only at Christmas time as it was either too hot, too cold, or too dark. It was separated from the main living spaces

Committing to a building project is a daunting, if exciting prospect enough, without budget parameters becoming a sobering consideration. So, imagine consolidating your dream brief with not only successful execution but daily reminders of your economy from a Passive House standard home!

 

A Certified Passive House ensures your home will be comfy and healthy all year round, worldwide. This is achieved through good design married with reliable products, and resulting in simple, efficient and cost-effective applications. The Passive House Planning Package (PHPP) tool generates optimum values for a building design which informs the selection of matching components. A system of product certification has been integrated into PHPP, which includes a component database orientated for energy balance the world over. Energy balance criteria for components factor in optimum lifecycle costs of products, which means the energy performance levels result in the lowest cost during an estimated economic lifecycle. These ‘cost-optimal levels’ are Passive house qualities.

example of energy cost saving

Full life cycle costs for renovation of single family home - Example of energy cost savings as calculated by PHPP energy balancing tool.

The growing concern for our planet’s environment has created an upsurge in Passive House compatible components. Together with increasing interest in recognised qualifications for designers and building professionals in recent times, this has led to a dramatic drop in the costing of Passive House standard buildings. With experienced and qualified professionals on board, recent research has shown the construction costs of Passive Houses and current industry standard developments are comparable. While more aspiring energy efficiency options can lead to higher investment costs, the approach of the Passive House concept is to find the optimal scenarios wherein increased efficiency results in doing without other conventional service components. With the competitive market of compatible components unabating, and current rising energy prices, Passive Houses present prominently as cost-optimal building solutions.

 

A major requirement in energy efficiency assessment is the concept of ‘energy balancing’. As this involves some background knowledge of physics and, the learning of important equations and how they work together, we’ll try and simplify it to fit into your lunch break. 

thermal bridges, regular VS passive house

Top: Neighboring (conventional) building with many thermal imperfections.

Bottom: Passive House building with very good thermally insulated envelope and only small thermal bridges above the windows.

Energy efficiency assessment or modelling involves combining a few basic elements in a building design. Firstly, the qualities of ‘heat’. Heat is a form of energy, called thermal energy. It can’t usually be seen and manifests as temperature. Another quality of heat is that it moves from warmer to colder bodies or spaces, therefore a source of high heat creates energy that can be used to increase the temperature of a colder body or space. To slow down cooling, a form of change or flux is needed, like insulation. This can also happen in reverse.

 

Secondly, the reduction of thermal bridges between the exterior and interior is a critical element in attaining high energy efficiency ratings. Thermal bridge-free construction is a basic principle of Passive Houses, ensuring the integrity of a thermally insulated envelope. These two elements combined with thermal resistance (heat flux), thermal conductivity, and heat transfer, are key values in the calculations used in energy modelling to push the limits of ‘cost optimal levels’ in Passive House designs.

 

Check in with our blog next week for more information on the different classes of the Passive House standard.