So we’re building a Passive House…

It’s been an exciting month in the tree changer house – we’ve (finally!) kicked things off with council for our new house build.

Are we crazy for doing this all again after a horrendous experience building in Sydney? Quite possibly!

Is it going to be the project of a lifetime?  Absolutely!

We’re doing something a little bit different this time and building a Passive House. We’re doing this for a few reasons:

• We want to be able to slow down our lives & work less in the future, and a building system where you spend a bit more upfront to save money in the long run, will help us a achieve that.
• We’re building in a stunning spot and wanted to build something that’s lower impact and better for the environment we live in.
• We seem to have a knack for finding new and unusual things to do!

While the Passive House is a relatively new trend in Australia, Europe has been building them for decades since the ‘Passivhaus’ concept originated in Germany in the early 1990s.

We’ve only just kicked off the approvals process with our local council, but we’re already discovering our new house is a bit of a novelty, and getting lots of questions about what it means and how it works, so here’s my non-techy run down.

The way I describe it is we’re building a house that uses very little energy, but delivers a healthy indoor environment that is comfortable year-round in terms of temperature and humidity. This is achieved by smart design and using special materials and building techniques.

We’re working with a brilliant team on this – Sue and Alice from Sue Connor Architects & Gaea Architects and Darryn from Eclipse Passive House.

A lot of time has gone into the design of the house and the materials it will use to make sure it makes maximum advantage of the sun and breezes for heating and cooling – including poring over 12+ months of weather data from our onsite weather station!

The team has taken this data and our brief for how we like to live and come up with an incredible pavilion design that is orientated for best effect on our building site. This includes lots of windows to take in the views and optimise the natural light and warmth our site enjoys.

The design also incorporates five key elements which are considered the foundations of a Passive House:

• Extreme insulation (my term!) – our house will be built with prefabricated panels that are packed with high–performance insulation.
• Airtight construction – our house will be sealed tight to ensure no uncontrolled air leakage.
• Use of mechanical heat recovery ventilation – basically our house will have a special system to let fresh air into the house without letting warm or cold air escape.
• High-performance windows that insulate and seal – in our case, we’ll have triple glazed windows coming to us all the way from Poland!
• No thermal bridges – our house will be built in a way that ensures there are no ways for warmth to escape.

We’re working toward having our new house certified as a Passive House, which means lots of modelling using special software to make sure it meets the (currently voluntary) standard.

For people that love detail, this means the house needs to perform within certain levels and limits set for a healthy and comfortable passive home, including:

• Heating demand limited to 15kWh/m2/year.
• Humidity maintained below 12g/kg of air (basically 65% relative humidity at 25°C) for at least 80% of the year.
• Temperatures of more than 25°C capped to 10% of the year if no mechanical cooling (aircon) is used.

At the end of this process, we should have a house we love to live in, that’s comfortable all year round. As a bonus we’ll be minimising our energy bills (the estimate is a Passive House typically saves 80-90% on heating and cooling versus traditional homes), reducing our carbon footprint and hopefully having a critter-free house thanks to it being airtight!

But the job won’t be done when we finish building. Passive Houses need ‘Active Users’ to make them work! This means we’ll need to make sure we have a good understanding of how the house works across the year and remember to open windows or adjust shading at different times to help the house do its thing.

Stay tuned for updates when we get building underway and if you’re interested to learn more about Passive Houses, check out:

• Gaea Architects and Sue Connor Architects
• Eclipse Passive House
• The Australian Passive House Association

Or leave a question below & I’ll do my best to answer it!