#1 Passive House Retrofit Melbourne
What is Passive House, and why are we undertaking a Passive House retrofit (Enerphit) of our house in Melbourne, Australia?
Welcome to this blog where I’ll be documenting the steps, trials, and tribulations of our attempt to retrofit our house to the Passive House Enerphit standard. As this is the first post, I thought it pertinent to briefly introduce what passive house is, and why we are embarking on this journey.
Firstly, a brief disclaimer. Whilst I do work in the energy efficiency sector, I am not a Certified Passive House designer. The intent of this series of posts is to share the experience from the ‘consumer/customer’ perspective rather than provide ‘expert’ advice. With that out of the way, let’s get into it.
What is Passive House?
The best introduction to Passive House is this 90 second explanatory video.
As the video explains, a Passive House has five main principles; thermal insulation, airtightness, heat recovery ventilation, high-performance windows, and thermal bridge free construction. The Passive House standard sets out the a strict set of criteria for airtightness, total heating, cooling, and overall energy demand, as well as occupant comfort and indoor air quality. This results in a comfortable, healthy and efficient house.
For retrofits of existing houses, the requirements are relaxed somewhat to account for things like the orientation of a house being fixed, and limited ability to remove some thermal bridges. The retrofit standard is referred to as “Enerphit”.
Why do an Enerphit retrofit?
There are several reasons and events that have led to our decision to undertake an Enerphit project:
I’ve always wanted to have a highly efficient, sustainable house
The poor quality of houses in Melbourne often results in mould, and the associated poor health outcomes. Passive House principles address this.
Melbourne is cold, particularly for someone who grew up in Queensland, and the idea of having a comfortable home that doesn't cost a fortune to keep warm is very appealing.
I have also experienced first-hand being in a completed Passive House, and this sealed the deal. The quality of product and workmanship was visible, and the feeling of comfort noticeable. The best comparison I can make is the difference between driving an electric vehicle vs a normal petrol or diesel car. Once you've experienced being in an EV it just feels right, and there's a similar intangible feeling of being in a Passive House.
If you're contemplating undertaking a Passive House project, I strongly recommend visiting an existing certified Passive House, and experiencing it for yourself.
Won’t it be prohibitively expensive / invasive / unachievable?
At the beginning of the process, we honestly weren’t sure what the answer to this was. Given all the potential benefits of a Passive House though, we wanted to find out. One thing that did appeal to us about the ‘Enerphit process’ was that it lays out a step-by-step plan to get to the end result without necessarily having to commit to doing it all at once. For example, you might be able to do the insulation and airtightness barrier now, but not do the high-performance windows, or you may do all measures but only for part of the house.
As we’ve just bought our house we aren’t looking to do major works, so throughout the process we’re looking at what we can do within our budget that isn’t invasive or impractical. There aren’t many examples of completed Enerphit projects in Australia, particularly those that don’t coincide with major renovations, so we’re testing the waters a bit here.
Helpful Resources
In the early stages of contemplating a Enerphit project I found the following resources very informative:
Recently released, this has plenty of example Passive Houses in Australia (mostly new build), and answers a lot of the frequently asked questions about Passive House.
EuroPHit Step by Step retrofits with Passive House Components
As you’ve probably gathered, Europe has been doing Passive House projects for much longer than Australia. This document was a part of a program called ‘EuroPHit’ that looked to increase the uptake of Enerphit projects.
This is a long document but highly focused on Enerphit projects. The pertinent reading is the Introduction and Basics section. It goes into much more detail in later sections but probably only valuable if you’re really keen.
A Guide to Passive House Building
Another good high-level overview of Passive House from the Australian Passive House Association
I’ll share more resources in later posts.
What Next?
In the following posts I’ll go into how we went about writing a design brief, and engaging a Passive House designer.