Retrofit case #1


Mr C is an older man who is living alone in his home, with ducted gas and air conditioning which he finds he is using more as he gets older. The ceiling had blow in cellulose insulation which he topped up with R3.5 fibreglass batts a few years ago, as well as rigid foam board under floor insulation. Just like my parents, he does not want to spend a lot of money retrofitting his home given that he reckons he won’t be around too much longer and whoever lives in his house next is likely to make alterations.

At the initial assessment with the blower door we found he had 10.37 ACH@50Pa which is lower than the average Australian home but is still way too leaky to be considered energy efficient. There was a large ventilation hole above his fridge and microwave which led straight into the roof space, a floor drain that led straight under the house, gaps around his doors and pipe penetrations as well as a few around architraves, skirting boards (felt through the carpet even), cavity sliding doors and electrical sockets. His gas storage heater had the short section of hot water pipe leading into the house unlagged and the PTR valve was exposed and toasty warm- wasting heat 24 hrs a day. His energy use has been  higher than average for a single person dwelling in Victoria, mainly due to the gas heating.

Given his desire for a minimalist retrofit we agreed on some simple draught proofing and installation of pipe lagging and a valve cosy. The valve cosy is pictured above- simple to install and relatively cheap. It is easily popped apart to activate the PTR valve as needed.


His leaky back door was fitted with a bottom door seal


and good quality compression door seals in a hardwood strip around the sides and top. The front door just needed the compression seals.


This is the floor waste in the laundry with the plastic grill insert removed, showing that it leads to the void under the floor with no more plumbing. You can also see the polystyrene sub floor insulation. We will go back and install a u-bend which he will need to occasionally fill with water as it evaporates, to create an air seal. Some extra plastic fittings required!

The biggest air leak was, of course, the hole into the roof space above the fridge. There was plenty of room around the fridge so the extra ventilation really is not necessary and is a big source of escape of wanted heat or coolth. We closed that off with a piece of unwanted corflute signage and sealed it with caulking, then covered it with insulation. Lastly was some general caulking around pipe penetrations, sealing up a leak in his dryer duct work and then recheck the blower door test to see how we’d done.


This shows the pressure gauge indicating the blower door is keeping the pressure difference between inside and outside at 50Pa and the air changes per hour (ACH) is at 8.196. That is quite a bit better than baseline and we still have the floor drain to fix. Blocking it temporarily brought the ACH down to 7.9. Is this getting to a level of air tightness that is problematic for adequate ventilation? Not even close. We’d have to get the ACH well under 5@50Pa before he would even have to start to think about it.

Mr C should notice that he doesn’t need to run his heater or cooler quite as much and that his bills go down, down, down! We’ll check back with him in a year and compare his spending on gas and electricity. Our total cost for the assessment (which covered all the areas of the Energy Freedom Home), report and this bit of retrofitting was around $500 which he should get back in energy savings over a year or two. There’s a link to the BBSN website with contact details here.


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