There is a future for your ex-govie
With a research grant from the Alastair Swayn Foundation, Iain Maxwell has shown that simple energy efficiency measures (such as installing insulation and glazing upgrades) can significantly raise the thermal performance of the typical Canberra ex-govie.
It is great to see independent, academic research that supports our beliefs and validates our tried and tested experience on many ex-govies over the last decade.
The study focused on the retrofit of a ‘Plan Type 405’ built in 1961 in Downer as part of the Canberra 400-series housing program. Using Nationwide House Energy Rating Scheme (NatHERs) thermal performance modelling software, this simple 112.6 m2, 3 bedroom, 1 bathroom home with good orientation rated 2.9 stars, well below the current National Construction Code (NCC) 6 star requirement for new homes.
The 2.9 star rating is based on a house with typical specifications:
brick veneer with no wall insulation
R3 ceiling insulation
no floor insulation
single glazed aluminium windows.
Sound familiar? With winter now here, this scenario makes us shudder!
The retrofit measures
Using NatHERS, six incremental retrofit scenarios were modelled to assess the impact on the EER:
RS1: draught sealing around doors and windows, and capping exhaust fans increased the EER to 3.7
RS2: adding minimum NCC levels of insulation for the ACT (R4 to ceiling, R2.5 to walls and R2.5 to floor) raised the EER to 5.9
RS3: then upgrading windows to aluminium double-glazed further increased the EER to 6.9
RS4: raising floor insulation to R4 and ceiling insulation to R6 raised the EER to 7.3
RS5: upgrading the windows to uPVC double-glazed further increased the EER to 7.9
RS6: upgrading windows to high performance aluminium triple-glazed raised the EER to 8.2
[Please note that thermal performance modelling assesses a wide range of factors specific to a house including size, orientation, size, type and placement of windows, as well as insulation and wall type. So not every ex-govie will start at 2.9 stars or can be raised to 8.2 stars. However you can make retrofit upgrades to any home and gain significant energy efficiency and thermal comfort benefits.]
Sounds good to us and is similar to what we modelled and then implemented in the work we did with the ACT Government and low income households back in 2012. Read that report here.
The cost and environmental impact of the measures
However the study does not stop there. It goes further to consider the cost and environmental impact of the measures. Chasing higher energy ratings leads to increased costs but also an increase in your carbon footprint (embodied energy) and greenhouse gas emissions. For example, RS6 includes high performing triple-glazed windows that come with a hefty price tag and triple the embodied emissions. This brings into question whether is makes good financial and environmental sense to go all the way to RS6, or whether there is a sweet spot around RS4 or RS5. The report concludes that both “RS4 and RS5 are cost effective, well-performing and balanced approaches”.
We agree that triple-glazing rarely stacks up from a thermal bang for buck perspective. The way we design at Light House, our projects don’t need it.
The carbon footprint of our existing homes
The report also draws an important link between housing supply and construction, and the embodied energy that already exists in our housing stock. When you take into consideration the overall environmental impact of a house, the study suggests that by retrofitting energy efficiency measures “we are in a position to capitalise on the embodied energy already invested in our homes, and avoid knocking them down just to make way for newer, larger and only marginally better [or perhaps even poorer] performing homes”.
We agree. It’s why more than half of the work we do at Light House is renovation and retrofit.
What does this mean for you and your own home?
Australia builds the largest homes in the world at an average size of 236m2. Even more disappointing is the fact that Canberra builds the biggest houses in Australia, and therefore the world, at an average size of 256m2!
It is time to start looking at our existing homes, and our desperate need for newer and bigger, differently.
So if you are thinking of knocking down your ex-govie (or any home for that matter) and building a modern home, we encourage you to think about whether there is a better way:
Retrofit may be enough
If you don’t need more space, perhaps a new kitchen or bathroom and a few retrofitted energy efficiency measures is all you need.
Read a classic case study where we saved the clients from building a whole new home! Turner Cottage.
Rejig Reno without extension
If the orientation or layout of your home isn’t good, perhaps a floor plan rejig (and an increased EER) is what you need.
We love these types of projects, and to show you how well this can work, check out these reno projects where we did not extend: Pettit & Sevitt Revival, The Fab-ode, Three Generation House, Bamford House and Vasey House (which was only extended by 1m2 for a pop-out wardrobe).
Alterations & Additions
If you do need more space, perhaps a reno and extension (plus a better EER) is in order. While it is not always the case, it can often be cheaper to renovate and extend than rebuild, and you are also reducing your home’s carbon footprint by capitalising on the embodied energy in your existing home.
We have done plenty of these types of projects too. Take a look at our gorgeous recently completed ex-govie reno Blackburn House, where we extended by just 21m2. Little Loft House is another a recent project, where we extended by only 13m2. Other examples are Curtin Reincarnation (which actually reduced in size), Chapman House, Black Mountain House and Longstaff House.
You can read the full report ‘Another Canberra House’ here.