Since 2021 when the schism in thinking about Passive House was painfully brought to our attention, the sceptics have edged their way into the world of mainstream architecture.
In Sydney a surprising number of influential architects will tell you “Nah, I just don’t buy it”
Why? you ask.
“Well in Australia, we like a bit of a ‘leaky building’,” they say. “Passive House is fine for Europens where it’s cold – but Aussies? We have a balmy climate, especially in Sydney and Brisbane, where you can let the breezes cool your house most of the time – and use aircon for the few months that they don’t. The grid is almost decarbonised anyway.”
The German developed methodology claims to build houses and now offices the way they should always have been built – with high quality thermal properties that don’t have incidental nail holes, faulty sealing around windows and doors, sloppy insulation and other impediments to high quality products that don’t cost the Earth to heat and cool.
Airtightness is a measure of that quality, and it’s balanced by a low energy, high efficiency heat recovery aircon and air filtration system that screens out pollutants.
The critics say it’s precisely the sealed nature of these buildings that has been implicated in overheating and mould issues. And they’re worried about the system ending up in building regulations and sustainability tools.
The problems could well be sheeted home to user error – people forgetting to turn the aircon system on or not opening doors and windows for normal aeration. But people will be people.
Then there is the steep cost of the filters for the aircon. And the overall costs of Passive House are high.
The sceptics say we can achieve excellent thermally efficient and comfortable houses without going to a full PH system.
The grid and decarbonisation
On the grid being almost decarbonised though, that’s not quite correct. Or it was until the past few months when the sheer number of data centres – and hyperscalers – roaring into the country with their ferocious appetite for energy (and water) became apparent.
Despite the massive advance in renewables, this is an era when we’re still far from renewable rich. They’re expensive both to build and in embodied carbon.
If DCs indeed swallow up 20 per cent of available energy within 10 years, as the experts predict (and who among us would say this number won’t go higher?) , there will be an even bigger need for energy efficiency, transmission lines and solar farms as businesses and households everywhere scramble to get off expensive fossil fuels.
Amplifying the problem is the severe shortage of skills and resources to “electrify everything” that’s already biting.
Anyway, do we want to live in fully airconditioned homes even for two months of the year?
In offices airconditioning is a serious cause of misery. Ask any mech-lec engineer and their facilities managers about aircon in offices. It’s the single biggest reason tenants complain, and leave if they can. Or sue if they can’t.
PH needs airconditioning but it’s low energy and its filtration system takes polluting nasties out of the air.
PH advocates will also tell you that the acoustics are also amazing.
Spend a single night in a PH bedroom and be instantly converted by the calm, the steady air temperature and the cleanliness, they say.
Besides many people don’t get the chance to live in places that capture the sea breezes and in this world of increasingly deregulated planning rules many apartments are on noisy, filthy roads.
It’s a tough debate but a good one
Let’s just say there’s a lot of emotion about this issue. So after our Timber and Codes Red debates, we’re asking you, the industry, to step in with the science, the views and a nod to our fast approaching climate future on this fraught topic.
The panel of building physicists, engineers and architects will help to answer your questions in a generous QandA session.
But first we will ask you to vote – before you hear the arguments and then again, after.
We’ll be wanting to know if we’ve helped you change your mind?
Because getting all the data, the science and the views on the table so you can have an informed opinion is always a good thing, because we don’t have time for anything else.
The article above could lead the uninformed reader to believe that a/c is always required in PH. Not so. The mech heat exchange ventilation system (MHRV) is always bringing fresh air into the building, regardless of what inside and outside temperatures are – it simply swaps the outgoing air’s internal temp into the incoming air, with surprising efficiency, assuming the windows and doors are shut. But it’s a free country – you can open windows and doors as you please! – there are no PH Police enforcing they be shut at all times!
A/c is used preferably in conjunction with ceiling fans, only when the internal temp is above or below a desired comfort level. The fans spread that conditioned air much more efficacy than the a/c on its own, making perceived comfort levels easier to achieve on even less energy.
The EFFECTIVE insulation and air tightness (measurable, testable, provable) mean there is less energy wasted – this is why PH runs on such low levels of energy, usually met with ease by a moderately sized rooftop PV system.
This isn’t theory – it’s ‘track record fact’, with [Andy Marlow please insert exact number of completed PH projects we’ve done here] low energy high comfort houses completed, occupied, and loved by their owners now (that’s just Envirotecture – plus dozens more by other PH designers and builders around the country).
Thanks for the clarification Dick… hope to see you on the night! We need that deep dive you guys have of experience… so many passions on the opposite side of this fence… strange as that seems
It’s a good debate, but we should be well past debates – and accept the Active Houses are the newish black.
This means that the Passive House is just basic – but it also should generate surplus energy: this makes it a certifiable, money-making Active House.