What is Passive House?
Imagine living in a comfortable warm house without significant drafts or temperature variations, an environment full of fresh air free of pollen and other pollutants, with minimal heating or cooling requirements. This is Passive House living.
Conventional Australian houses are poorly built and rely on expensive active heating or cooling systems to maintain an acceptable range of internal temperatures. These systems are usually powered by expensive fossil fuels and contribute a
significant proportion of Australia’s greenhouse gas emissions.
By contrast Passive Houses are built with a highly efficient external shell so they stay at a comfortable temperature year-round with minimal energy inputs. The buildings are almost “passive” as they require hardly any active heating or cooling systems.
HOW DOES IT WORK?
The well-insulated airtight house is naturally heated through targeted passive solar gains combined with waste energy from internal sources and a heat recovery ventilation system.
Cooling requirements are minimised because of the highly insulated airtight fabric. High performance glazing is careful orientated and strategically shaded. Additional cooling is provided by the heat recovery ventilation system and sometimes from air conditioning powered by electric heat pumps.
Passive House is today’s most energy efficient building standard.
The 5 Main Principles
A continuous layer of insulation from the foundation to the roof cavity creates a highly efficient unbroken building envelope to minimise heat gain in the summer and heat loss in the winter, maintaining a comfortable living temperature year-round and reduced risk of condensation.
GLAZING (ORIENTATION & SHADING)
Glazing is the weak spot in the buildings thermal defence and typical poorly sealed single glazing is a huge cause of unwanted heat losses and gains.
By contrast, Habitech Systems use energy efficient passive house windows that are highly insulated with low-emissivity double or triple glazing and thermally broken or non-metal frames. Using these high-quality windows with optimal positioning and shading ensures the correct balance of solar gains are admitted when beneficial and excluded when not desired.
The building envelope must also include the windows. Single glazing is common here in Australia and is commonly known to be the weak spot in the buildings thermal defence, often being the coldest/hottest place in the house. Passive House windows are highly insulated with low-emissivity double or triple glazing with thermally broken or non-metal frames, strategically positioned to make optimal use of the sun’s energy year-round.
Our panel system with its continuous layer of insulation makes it easier to achieve thermal bridge free construction. This means there are minimal weak spots in the building envelope where a conductive material spans between exterior and interior surfaces. Avoiding penetrations through the insulation will lessen the chance of thermal bridging that causes uneven temperatures and moisture damage and mould growth from condensation.
Creating an airtight barrier free of gaps and cracks ensures a comfortable internal environment, boosting energy efficiency, while preventing draughts and mould. An airtight envelope allows the use of highly efficient heat recovery ventilation systems to be installed.
A Heat Recovery Ventilation (HRV) system is the lungs of a Passive House building, replacing stale humid indoor air with fresh filtered outdoor air. It also maintains a comfortable temperature by recovering the energy from the indoor air and transferring it to the fresh air being distributed throughout the home. In summer the warmer incoming air is cooled by the outgoing air. In winter the warmer outgoing air heats the cooler incoming air. This ventilation system reduces environmental pollutants and can be beneficial for people with allergies. You can still operate windows and doors as usual.
Comfortable temperatures close to 21C without drafts. Reduced seasonal and daily temperature variations.
IMPROVED AIR QUALITY
Health benefits from continuous supply of filtered fresh air (HRV system) reducing dust, pollen, odours, excess moisture and pollutants. If you wish, you can still open windows and doors as usual.
Comfortable conditions are maintained even in the event of a power outage or possible fuel shortage concerns. A stable internal temperature is also a good precautionary measure against climate change.
Reduced energy consumption from conventional heating and cooling systems (80-90% less than typical constructions).
Using Habitech Systems' insulated wall and roof panels creates a very quiet airtight house.
Advanced design, better building components and proven building science ensure an environment free from mould and condensation creating a healthier and longer lasting home.
Simple mechanical systems and high quality durable building components are simple to operate and inexpensive to maintain.
The marginally higher initial costs of a passive house building are far outweighed by the long-term savings required to run larger heating and cooling systems in a conventional building.
NET ZERO POTENTIAL
Simply installing a renewable energy system could turn a passive house into a Net Zero energy home or energy exporter. Some clients go fully off-grid and others receive credit payment from their electrical utility networks.
Computer energy modelling during the design stage is proven by blower door testing during construction stage. Independent third-party verification after completion provides assurance and verified performance. Habitech also monitor energy generation and consumption in completed projects for research development, and quality assurance purposes.
WHY CHOOSE Habitech Systems TO BUILD YOUR PASSIVE HOUSE?
Modular construction is perfect for Passive House. It ensures a simpler, quicker, more cost effective way to achieve a beautiful passive house.
Habitech is one of the few established modular construction companies offering fully bespoke architecturally designed houses to PassivHaus standard. Our system offers complete freedom in design and is appropriate for all types of projects, sites and climate conditions.
Our team are all experienced architects, designers and documenters with completed projects in climate zones including VIC, NSW, TAS, ACT and in New Zealand. Every project is unique and our high performing envelope system means that design innovation and architectural beauty never suffer for reasons of cost or environmental performance.
Our system is based on structural insulated wall and roof panels that make it very easy to achieve air-tightness and elemental u-values with no additional cost or mitigation measures required. Walls have a base insulation rate of R4.3 and Roof Panels R5.3. This level of superinsulation is deployed in a continuous layer with no noggins, studs, battens or rafters to act as thermal bridges.
The modules are prefabricated to a very high degree of tolerance so they fit together very closely when installed on-site with their airtight junction components. The rapidly assembled panels require no additional weathering or cladding layers so it is far easier to ensure airtightness with simple taping at edges. The robust surface layers of MGO and Plywood (or metal sheet roofing) eliminate the cost and expense of additional membranes with their practical difficulties of ensuring air-tightness on site. These durable panel skins are immune to the risks of puncture or rips that affect membranes and cannot be installed incorrectly through ignorance laziness or oversight.
HEAT RECOVERY & RENEWABLES
All of our projects include the design, detailing and cost provision for MVHR and renewable technologies as standard. Our airtight envelope ensures these technologies are integral to the planning and performance of the house from the outset so they are never omitted later for cost reasons.
As a standardised system it is easy for the designers to accurately model all of the approved certified elements, details and junctions exactly as they will be built on site. Unlike traditional construction methods where energy modelling is based on fantastical ideal scenarios, our buildings do not vary based on installer incompetence or shortcuts on site. In fact our experience of post-occupancy monitoring shows that our projects are performing better than expected.
Monitoring and assessment – Depending on client requirements Habitech can install either temporary or permanent energy monitoring equipment in the completed home. We can provide a solution that enables the home owner to monitor their energy generation, export and consumption by category over set time periods. An example of this is our Reservoir project that has been monitored in use for more than 18 months. This home achieved passive house performance and a significant energy surplus bonus to the owners despite passive house performance never being part of their brief. It wasn't a specific design objective so it actually achieved passive house performance by accident!
Our design philosophy does not see passive house performance as an additional layer or cost. It is simply a given with our modular system.
passive house - habitech senior designer
Niall has over 11 years experience in sustainable residential and commercial building design, both in Ireland and Australia. He co-founded and ran an architecture practice in Dublin where he designed and completed highly energy efficient homes and heritage renovations.
Since moving to Melbourne Niall has designed many award winning homes on rural and urban sites, including passive house projects. He recently designed and led two mixed use apartment and medical centre projects currently in construction Malvern and Clayton. These cross laminated timber structures will be built to Passive House standards and will be the first of their kind in Australia.
Niall joined Habitech in October 2017 as senior designer and head of the passive house team.