Passive solar design & passivehaus
Passive Solar Design and Passivhaus are design philosophies gaining a lot of traction in the construction industry. Here we look at the differences between these approaches so you can be better informed in your research on building a sustainable home.
Passive solar design
This is a major part of energy efficient design and with careful design considerations can make up 90% of the overall energy efficiency of your home. There are several factors to consider in homes designed for the climate with the most important being building orientation, materials selection, ventilation and air-flow, and the location of living areas, services and wet areas. The term “passive solar” can be somewhat misleading as a passive solar home requires inhabitants to actively operate the home. It’s the use of design solutions that will optimise solar access and maximise energy efficiency that can help homes remain comfortable for longer all year round.
In the South West region of Western Australia, from Geraldton in the North to Pemberton in the South we experience a Mediterranean climate. The implementation of correctly located thermal mass in our homes becomes important to offset heat gain and heat loss throughout the year. To maximise performance, both horizontal as well as vertical mass are needed. Just as important is the size and orientation of glazing as windows incorrectly located can be a weak spot for heat loss and heat gain.
This is a technique developed in Germany with a set of rigorous standards set in place to make conventional artificial heating/cooling obsolete, making homes extremely energy efficient. According to the Passive House Institute US, these standards will change depending on the climate in where these homes are built. The German Passivhaus Institute (PHI) believes the standards as set will work in any climate.
The design principles typically used to meet the standard are: super insulate the building envelope, eliminate thermal bridging, make it airtight, install an energy or heat-recovery ventilator and use high-performance windows and doors. The design is then modelled using the Passive House Planning Package (PHPP) software tool to ascertain energy gains and losses. On average passive houses are reported to be more expensive upfront than conventional buildings.
Ultimately, home owners are looking for a comfortable home that meets their needs, and future needs, as well as minimises energy use and their impact on the environment. This is the heart of sustainable home design.