Passive House: The Value of a Healthy Home 5

Tuesday, March 15th, 2016
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I’m not sure I could find anybody, should I try, who would openly and readily agree that the type of home they want to live in would include stuffy rooms, condensation on the windows, cold floors, draughty doors and dust galore.

Why would you?

But that’s what most of us endure in our buildings in this country (perhaps I’ve lived in more than my fair share). Worse still, many of us develop ailments like asthma and allergies; worst cases see others contract skin or respiratory conditions due to issues such as mould or mites. Others suffer severe worsening of medical symptoms due to cold living conditions, perhaps coupled with high humidity in winter.

We’ve perhaps become so used to these issues that we think of them as part of life; I know that condensation on the windows and a bit of mould in the musty corners of dark rooms was something I thought was standard growing up. In reality, these are reflections of poor building design and/or construction practice, and all entirely or largely avoidable.

The picture painted here is one regarding of quality of life. I’ve perhaps been lucky to avoid ailments like asthma, perhaps not being otherwise predisposed. But I can’t think of a single house I’ve lived in that hasn’t either been bitterly cold in winter or used a whole lot of energy to keep warm (and many, many trips to cut firewood!) There were winters where I slept in two layers of pyjamas and blankets so heavy they could have suffocated me, as well as summers where sleep would never come as it was impossible in such heat. We’ve all been there.

Would I pay more for a home that was comfortable, healthy and cost less to run? Readily. And doesn’t that imply value for this provision? Yes, of course. How will I do this? By applying good building principles, notably the application of the Passivhaus standard. There is no other standard that delivers the benefits of indoor environment quality and energy efficiency, while maintaining a focus on the economic impost.

At its core, the Passivhaus, or Passive House, standard is an exercise in affordability. The entire premise of the standard’s criteria is based around extensive analysis of the cost impact of the approach. Passivhaus is placed exactly where it is on the cost-energy curve precisely because this is the point at which major heating systems (a boiler or furnace) are deemed unnecessary because of the thermal comfort and energy efficiency gained through the approach.

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Recognising that this sweet spot has been analysed for the European context, we can still take the principle and apply it to the Aussie situation. It would be near impossible to find a new home being built that won’t have air conditioning, probably used for a whack of cooling in summer, but also intended for heating through a longer than commonly realised heating period.

According to the CSIRO, Melbourne has over 1,300 hours per year with temperatures below 10 degrees Celsius but just 170 over 30 degrees Celsius; Sydney has more heating than cooling hours, but temperatures sit in the 10 to 30 degrees Celsius band over 95 per cent of the time.

Key facets of the Passive House standard include the provision of a highly insulated and airtight building envelope as well as a significant reduction in overall building energy use, including plug loads. Key design factors that help with efficiency include the use of daylight, natural ventilation (when outdoor conditions are favourable) and careful selection of lighting and major appliances such as fridges and dishwashers.

With over 50,000 Passivhaus projects in climates ranging from Antarctica to Jakarta, the breadth of solutions has surely been examined.

Imagine that your accountant came to you and said you can’t have that marble benchtop or those beautiful timber floors or those fantastic pendant lights because the return on investment doesn’t stack up. This is a very familiar argument to anyone who’s ever done assessment of renewable energy systems – if the ‘payback’ doesn’t match or exceed the traditional financial models that the numbers guys are used to assessing, then it’s a no-go.

Well, as well as the obvious (reduced energy consumption, reduced carbon emissions, lower demand resulting in reductions to grid infrastructure [on a grand scale] or smaller PV systems that meet net energy use [local scale]), maybe we could just start applying these systems because it feels right – because there is a greater impetus than your bank balance to moving away from fossil fuel use. Then the renewable argument starts to win.

That’s also the case with a building fabric approach such as Passive House. While the net effect of envelope upgrades over mechanical system savings may add costs to buildings, the intangible benefits can and will reign supreme. Improvements in indoor environment quality surely ‘pay off’ when you consider that children may then not develop respiratory ailments such as asthma – Australia and NZ rank among the highest in the developed world (OECD) for asthma hospitalisation.

And how about improved environments that result in better learning outcomes? Elimination of irritants and allergens in air supplies can result in fewer complaints from those who suffer when levels increase, and it’s a well documented outcome where sick days (particularly in commercial buildings) reduce in buildings with great IEQ.

There has been some research on house prices in Australia and overseas showing that the price fetched at sale for green or eco homes is up to $140,000 more than similar homes. If you want a green home, they can be relatively hard to locate and competition is rife. This surely adds fuel to the argument that ‘value’ means different things to different people.

Achieving the Passive House standard often comes at a premium, and this is largely attributable to extra costs for better glazing, extra insulation, heat recovery ventilation systems and build costs associated with airtightness measures. The industry has rapidly caught up with demand, though, and the availability and knowledge is very much meeting demand. In some instances, the suppliers and manufacturers are becoming the educators, bringing with them a wealth of expertise from overseas and being willing to engage with the industry and public for the sake of improving local practices.

There is also renewed focus on homes and health; as Australia’s climate heats up, the cost impact to, as well as the readiness of, the health system is gaining scrutiny. This week, the Climate Council highlighted that heat stress is Australia’s number one natural killer, accounting for more deaths than floods, cyclones, bush fires and storms combined. A key point was the increasing risk of this danger despite the increasing prevalence of homes with air conditioning, and critical risks like power failure. The report noted a call for more considered response, such as policy around how urban areas are designed.

It’s all the unquantifiable benefits of good design and construction approaches that mean the standard is gaining traction in key areas – housing, education and health. In these types of developments, the outcomes go beyond pure financial measures and it becomes less about the bottom line.

This single measure that developers use to measure success becomes blurred amongst things like health and amenity, and a triple bottom line approach prevails. Suddenly everyone is happier: the bean counters, the occupants and the environment.

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  1. Peter Tomkinson

    I could agree wholeheartedly if low energy equated to a very healthy home but unfortunately many of the so called Green Houses and the features prioritised in their design and construction WILL contribute to the un-healthiness of the environments they create. Put human health first, and then add passive house concepts where they benefit the health of people who will live in them and I am all for it. Mould needs only moisture, air and a food – sealed up housing, with im-permeable structure and artificial blown air heating in a chemically laden plastic interior is a recipe for mould, dust and mites. Cough!!

    • Dale N Bickenbach

      Mr. Tomkinson, please I encourage you to study more prior to inserting comments. Comfort, healthy indoor quality, and energy conservation have long been incorporated into the design of the most advanced home/facility design. I would invite you to attend one of the conferences in North America either as a vacation, excuse to travel, or as a business trip to see what the Northern latitudes are achieving. My preferred group,, has gone beyond the initial passive house concept, PHI, to allow for differences in climate, which translates into better material quantity usages, money saved by using what is actually needed in the area. This is done in concert with quality materials, the best building science, and indoor quality requirements.

    • Willa Montague

      Did you actually read the article?

  2. Elrond Burrell

    Peter you are right about "low energy" and 'so-called green' houses. In contrast, the Passivhaus Standard is a rigourous scientifically established standard that protects human health against all those issues. It requires rigorous quality assurance during design and construction to endure the requirements are met, unlike other 'good intention' standards.

  3. Jason

    Nice article and well said. FYI the graph has the construction and heating energy costs legend swapped though. When you eliminate the furnace the construction costs drop while the energy costs are a linear function of the energy used to heat the home.