I am an architect and a Certified Passive House Designer. Over the last ten years my practice has completed numerous residential new builds, alterations, renovations, and extensions in Melbourne and regional areas.
I am now pleased to be offering bespoke high-performance, ultra-low energy, comfortable and healthy Passive House design to our clients.
As an Architect, I am passionate about Passive House, and excited to be involved in the early uptake of this fast-growing movement in Australian construction.
This post contains much of the important information we teach our clients about Passive House construction in Melbourne, and the regional Victoria.
The Benefits of Passive House vs Regular Construction
What is Passive House?
Passive House is a contemporary innovative building standard that is creating new insights for architects and engineers. Industry responses are positive, with market forces driving economics and innovation, with highly efficient products being created.
The Passive House Standard was born out of a conversation between building physicists Wolfgang Feist and Bo Adamson, who asked themselves how buildings could be created in a sustainable, ultra-low energy way. This resulted in research that led to the first Passive House being completed in Germany in 1991, which provided a built example of ultra-low energy, with comfort, affordability, and excellent indoor air quality.
The building was a row four terrace houses, which still preforms as it was planned. With the annual energy use being consistently less than the prescribed 15 kWh per square meter of habitable space.
Passive House homes are a combination of comfort and ultra-low energy use. The key elements of Passive House buildings include high performance windows, continuous high level of insulation, air-tightness, thermal bridge free construction, and mechanical ventilation with heat recovery.
Appearance wise, Passive House can be adapted to any architectural style. Passive House is a performance standard which does not prescribe a specific construction method. It must meet specific energy demands, whilst designers can choose the best construction method to meet these targets.
Increased comfort, less energy consumption
With Passive House buildings careful planning and procurement is critical. Attention to detail is paramount to ensure a minimal energy demand, with the heat of four people (or 10 tea light candles) being able to keep an area of 20 m² in the height of winter, even in extremely cold climates. In practice a Passive House is not heated with tea lights; however, the equivalent energy use is used with efficient heating systems in combination with mechanical ventilation with heat recovery. And in Summer Passive House homes provide great comfort levels, with no or little reliance on air conditioning. Thus, with a Passive House the energy needed for heating and cooling is extremely low.
What helps make Passive House more comfortable?
The Passive House has five principles, which are:
- Continuous high-level of insulation
- High performance window frames and glazing
- An airtight building envelope
- Mechanical ventilation with heat recovery
- Thermal bridge free design and construction
The super-insulated continuous envelope of a Passive House keeps the indoor temperatures at a consistent comfortable level, without temperature extremes or draughts, whilst also providing an extremely quiet home from external noises from busy urban areas. And, the mechanical ventilation with heat recovery (MVHR) provides a supply of continuous fresh filtered air at room temperature, which provides protection from pollutions, smoke, pollen, and odours.
To achieve Passive House ultra-low energy levels high quality building physics are used, with the three key aspects being a continuous insulation, an airtight building envelope, along with thermal bridge free construction. This results in the building having structural longevity, with ultra-low risks of condensation within the building structure (and interiors).
Future-proofing your home
Since 1990, the uptake of the Passive House Standard has been huge, and as of 2016 there have been approximately 60,000 buildings completed world-wide; whilst it’s popularity in Australia is rapidly increasing with 100s of buildings in the design and construction phase. Building a Passive House is not only a sound investment, it simply makes sense.
Several hundred Passive Houses have been monitored and tested, with consistently positive results.
Economics and Affordability
Passive House projects are high performance and high-quality buildings, where the initial investment costs are typically – but not always – higher due to the additional design input and superior building components. However, over the building’s life span they are more cost effective than your standard build, due to the low running costs.
When it comes to Passive House and building costs there are misconceptions. Typically there is a premium, however, with smart design this can be kept to a minimal, and in some cases there can be a substantial saving.
There is a case study of two completed houses in Victoria where significant saving were made taking the projects from passive solar design to Passive House. They were both fully design, documented, and costed as passive solar houses, then it was decided to bring them up to the Passive House Standard. One project saved 7% of the construction costs, whilst the other saved 15%. You can read more about these projects here.
There is also another interesting case study on a completed project, where they have concluded that the cost premium for Passive House in Sydney is negligible. This case study can be found here.
Passive House also has the benefit that it doesn’t require thermal mass, unlike a passive solar design. This provides additional savings.
Ultra-low energy is the key component of Passive House. When compared to a standard building, there is typically a reduction of 90 percent in energy use for heating and cooling.
When you take these running costs into account, Passive House is even more cost effective.
Reducing energy requirements further
To further reduce the energy use it is important to use efficient electrical appliances. Whilst to run the mechanical ventilation with heat recover is negligible with it being roughly 2 kWh/m², which is less than an LED light bulb.
Passive Houses are user-friendly and uncomplicated and don’t require user manuals to operate. And, they provide comfortable temperatures, no draughts, and fresh air.
The Passive House Standard is a voluntary ultra-low energy standard, with people being drawn to it for its benefits and simplicity. It can be built by anyone and it makes a sustainable contribution without compromising on comfort, with construction products and the Passive House Planning Package (PHPP) software being accessible.
Whether a Passive House has a basic or unique design, it is always something special.
Adaptability to local climates
The Passive House Standard has a general methodology that is used worldwide, whilst each project will have individual components that respond to the local climate.
For example, to ensure comfort during hot periods in warmer climates greater attention is given to passive cooling, with shading devices and natural ventilation. Thus, each Passive House building will have individual characteristics that are optimised to the local climate.
With ultra-low energy use, Passive House makes the use of renewable energy more affordable with the demands being less, for example you would require less photovoltaic panels than a standard build as your energy demands will be minimal. Passive House ultra-low energy use significantly reduces CO² emissions and provides a positive contribution to minimising climate change.
FREQUENTLY ASKED QUESTIONS
FAQ #1: Will building to Passive House Standard be more expensive?
With smart design an architecturally designed, custom-built, Certified Passive House can be delivered for the same, or even less, than an equivalent house built to the minimum standards required by National Construction Code (NCC).
In milder climates like Sydney, Passive House projects have proven to be cost neutral. And there are examples of houses that have been built in Victoria, where it was cheaper to build the same design to the Passive House Standard, as opposed to solar passive design.
Where it can be more expensive is when you are taking a new home built by a volume-builder – which are designed to be mass produced, large, and inexpensive – to the Passive House standard.
FAQ #2: Is Passive House different to Passive Solar design?
There are common threads between Passive House and passive solar design, however, they are distinctly different. Passive solar design has principles which guide the design, but it lacks in comfort, health, and ultra-low energy use.
A Certified Passive House designer will use passive solar gain – if available – and will accurately model its effects on the home’s overall performance. And it has the health and comfort benefits of constant ventilation, even if no one is home to open the windows.
Passive solar design requires north facing orientation for controlled solar gains, appropriate shading, natural ventilation, along with thermal mass to minimise fluctuating indoor temperatures. In many circumstances passive solar is not feasible due to the site orientation or over shadowing from an adjacent site.
Passive solar design sets out to maintain comfortable average temperatures, but averages can disguise substantial and uncomfortable changes in indoor temperature over a 24-hour period.
There is also the challenge of adequate ventilations vs comfortable indoor temperatures. When outdoor temperatures are extreme windows need to be kept closed to assist in maintaining comfortable indoor temperatures, which limits fresh air.
FAQ #3: Passive House was developed in Europe, is it relevant for an Australia’s climate?
Passive House was developed in the cool temperate climate of Germany, but there have been over 100,000 projects completed worldwide in a range of climate types ranging from very cold, to dry, to humid.
In Europe they focus on minimising heating, whilst in Australia we also consider limiting cooling. Passive House is flexible, it is a performance-based standard, which does not dictate how it is achieved.
Australia has many different climate types, and a Passive House designer uses the modelling software and local climate files in inform the design. A Passive House in Hobart will require more insulation and different glazing to achieve the ultra-low energy use when compared to a location like Darwin.
Data ensures Australian homeowners obtain all the benefits of Passive House at a cost and complexity that suits their site conditions and local climate.
FAQ #4: Can windows be opened in a Passive House?
Windows can be opened in a Passive House, and it is ok if you want to maintain the indoor-outdoor feel by leaving your external sliding doors open, hear the birds, or listen out for your children.
But if you live in a noisy area, or it is hot or cold outside, you will appreciate the quietness of a Passive House when the windows are closed.
In addition to the thermal qualities of double or triple glazing there are also acoustic benefit.
It is not necessary to open windows as the ventilation system is providing continuous fresh filtered air at a constant temperature into your home.
FAQ #5: Passive Houses are airtight, is this healthy?
Passive Houses are airtight, which is different to being sealed. They are healthier than a standard build due to the mechanical ventilation system with heat recovery (MVHR), which continually removes stale, damp air from the interior spaces, and replaces it with fresh filtered air.
Tamamea Passive House
This is a great video to watch about a Passive House in New Zealand.
Please note this particular house it didn’t need heating or cooling system, due to it being in an ideal climate ‘sweet spot’ for building a Passive House. In Melbourne it is typical to have heating and cooling system – which can be as simple as one or two split systems – which are used on the rare occasion where the climate is at it’s extreme.
Get advice from a certified Melbourne Passive House Architect
I love talking about Passive House, so please get in touch if you want to learn more about it’s suitability, costs, processes, and what to expect. I can be contacted for a free consultation via my contact page to arrange a time.