Is Retrofit expensive?

There is so much confusion in the housing industry about retrofitting Australia’s homes. Lots of people (builders, architects and real estate agents included) will tell you that it’s too hard and too expensive to improve the energy efficiency of our existing houses. WRONG! It’s not rocket science, its building science.

Watch the video below to hear Jenny talk about the three levels of Retrofit work we have done at Light House. The budgets vary enormously but they all have significant impacts on energy use, comfort and health.

If you want to know more - come back and read the additional text below the video.

Unfortunately, some of our own integrated architecture and science work at Light House has been used to undermine the value and cost-effectiveness of our science-only services (see links to info about that and some case studies at the end of this blog).

We have done many great architectural renovation projects over the years. All of them have integrated science with the design process and resulted in significant thermal improvements while also architecturally rejigging, renovating, refreshing, often slightly extending and, nearly always, completely modernising.

These projects have budgets in the hundreds of thousands of dollars, however, only a fraction of that budget was spent on energy efficiency measures. Sadly, this where the confusion begins. When main stream media articles like this say things like: “The recent retrofit of the Little Loft House in Canberra increased energy efficiency from 3.8 stars to 7.7 stars, for a cost of $400,000” they are sending the wrong message.

A completely incorrect message that perpetuates the idea that its all too hard and expensive to improve existing homes and the millions of people that live in them will just have to keep suffering… or knockdown and rebuild a new one to ever be comfortable (NOTE: this is not what we want or need if we’re serious about a low carbon, climate resilient future and completely unaffordable for the vast majority of people).

The truth (backed by science) is that we could have taken the energy efficiency rating of this tired, old, daggy 1980s house from 3.8 to 7.7 stars:

  • without extending it and adding a new loft space

  • without completely stripping it - removing walls and moving walls

  • without doing a whole new kitchen

  • without doing a whole new bathroom

  • without adding a second toilet

  • without new flooring throughout

  • without a new study

  • without new wardrobes in all bedrooms

  • without two new window seats and integrated bookcases

  • without custom joinery throughout

  • without new heating/cooling

  • without new hot water system

  • without new kitchen appliances

  • without a new water tank plumbed to the toilet and laundry

  • without new pergola and outdoor entertaining area

These things did not affect the amount of energy required to keep the house at comfy temperatures all year round but these things cost hundreds of thousands of dollars. The clients chose to do these things because (like thousands of Australians every year) they wanted to upgrade their home aesthetically and functionally. They did not do the wrong thing, they were fully informed about the costs and thermal benefits. By contrast, thousands of Australians collectively spend millions of dollars superficially renovating their homes each year without doing any thermal upgrades - this is the horrifying story and one that journalists and TV shows need to pay much more attention to.


The things that changed the EER (which is about the thermal properties of the building envelope ie. heating and cooling only) were the insulation, draught sealing and new double glazing - these things were less than $60k.


When we add in the move off gas and making the switch to all-electric, which has caused energy bills to drop even more, then you’ve got another $15k or so. In the case of this home that was for two RCAC split systems, ceiling fans in all bedrooms and living areas, a hot water heat pump plus induction cooktop).

As you’ll see/hear in the video, and from reading our other case studies, much lower budgets can achieve great things.

Read about our science services here and some case studies here.

Light House Architecture and Science