New Efficiency for an Old House

The property is a 50 year old, single-storey brick veneer home situated in the Apollo Bay township. It has a tiled roof and some changes has been to make it more energy efficient. Home to a young family with two children, the house is ripe for a major renovation which is planned in the next few years.

The Owners' Aims

Most immediately the owners want to reduce the large energy bill as well as improve thermal comfort, especially heating. They have recently replaced an old electric storage hot water system with a more efficient heat pump and have just stopped using the old inefficient split system for heating. More generally, the owners are also concerned about frequent power outages and are keen to build more self-sufficiency and resilience into the house through solar installation.

The Assessor's Findings

The assessor observed the south-facing orientation of the main rooms which are unable to access winter sun. He also noted the potential for solar on the large expanse of north-facing tiled roof.

The main household appliances were energy-intense, inefficient and costly to run. These included a gas cooktop with an extractor fan, an electric oven and a Nectre slow-combustion wood fire. A review of the energy bills revealed the house was using 7kWh per day on hotwater alone before the heat-pump was installed.

An investigation of the power meter plus the north facing roof were highlighted as good features for a potential solar system.

Regarding insulation, the assessor identified old insulation in the ceiling with many gaps, and noted that insulating brick veneer is problematic. There was also no insulation on the hotwater pipes in the roof. The owners reported condensation in the bedrooms and the assessor advised that air vents in walls do not provide as much fresh air to inside as would ventilation from windows.

The thermal camera revealed heat leakage around the old incandescent downlights, and these further undermine the insulation. In the bathroom, there are two penetrations (for ceiling fan and heat lamp) that are sources of draughts and heat leakage; similarly the roof-venting in the toilet causes draughts. There are some gaps between the walls and cornices and above some windows.

Currently, there are no effective window coverings, so there is thermal leakage occurring at all windows. Unfortunately, the style of the windows does not allow for secondary glazing.

The Assessor's Recommendations

The assessor made many recommendations to improve the thermal envelope of the building and cut power cost by reduced consumption. He suggested:

  • the replacement of: downlights with IC-rated sealed units; the kitchen exhaust fan with a rangehood, and the bathroom fan-heater with single extractor fan-heater unit with back-draught protection (re-plaster the void);

  • the installation of: a shower dome over shower to reduce condensation; cellular blinds in bedrooms, living room, kitchen (Veneta brand is cost-effective option) to improve window thermal performance and stop unhealthy condensation;

  • wall insulation could be installed and the tiled roof makes this do-able.The assessor recommended the company Enviroflex, and using the wall insulation type 'KNAUF superfill';

  • roof insulation also could be upgraded after downlights replacement, to fill all the gaps and upgrade to 4.5R, going over the top of existing insulation.

Other inexpensive suggested DIY improvements which the owners' appreciated were insulating the hot-water pipes running across the roof cavity and bringing light into the hall way by of installing a 'Kimberley Illume' solar 'skylight' which has a small solar panel on the roof that drives an internal LED light fitted flat on hall ceiling.

In the bigger, longer-term picture the assessor strongly recommended designing the renovation to capture as much winter sun in the back rooms as possible. He also strongly supported installing a solar system on that north-west facing roof space to help power the upgraded appliances such the heat-pump hot water and a new the split system for heating and cooling.

From The Owner's Viewpoint

The assessor first recommended that our plan for a renovation really should include reducing the extent of the back porch to allow more winter sun to penetrate our main living and bedrooms. This is important to us. As well, when we consider a solar installation, we know now that it should be as large as we can afford in order to support general electrification of the house". In summary, the owner said “This is the sort of thinking that is really valuable to us”.

Richard shows thermal imaging of heat loss due to intrusions into ceiling - bathroom light, heater and fan

Themal imaging camera illustrates heat loss around unsealed downlight