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Home > Example Homes > Papakowhai Renovations - House 10

Papakowhai Renovations - House 10

Home Details

Building area
170 m2 m2
Year built
4 bedroom(s), 1 bathroom(s)
House 10 in the Papakowhai Renovation project saved 30% on annual power bills, through full insulation and double glazing combined with an efficient heating source, improving indoor temperatures and family health. Solar water heating and wetbacks on both the solar system and woodburner provided most of the family's hot water needs, reducing hot water power bills considerably.

House 10 was part of Beacon Pathway's first renovation research project which tested various combinations of energy, water and indoor environment retrofits on nine ordinary 1970s homes. The houses were monitored before and after the renovations to determine how well each house performed.

Results showed that simply providing ceiling and underfloor insulation does not, on its own, make a home warm, dry and healthy. Rather, to recognise significant benefits the whole thermal envelope must be targeted – floor, ceiling and walls – and coupled with an efficient heating system.

House 10 is one of the Papakowhai success stories. Built in the 1970s, it is typical of the split level homes in the hilly suburb, oriented to the view rather than the sun. Additionally, insulation was not included in homes of this era, and the split levels and variety of building materials and systems – from skillion to cavity roofs, and suspended to uninsulated concrete floors – produced homes considered difficult to energy retrofit. The house had been poorly maintained, with timber window frames rotten through in places, drainage problems, and leaks in the building envelope. The homeowners had been progressively relining parts of the house, and installed double glazed window units in the bedrooms.

To improve its performance, House 10 underwent a major renovation:

 double glazing was installed in new aluminium frames
 insulation was fitted in the walls (R2.4 batts) and under the floor (R2 foil backed batts)
 a polythene vapour barrier was installed under the floor
 the skillion ceiling was lowered and insulated with R3.6 batts, and the remaining ceiling was insulated with two layers of R2.6 batts
 an old wood burner was replaced by an NES-compliant wood burner with wetback. Spot heating was used in the bedrooms.
 a solar hot water system with a wetback and a new wrapped 300L cylinder was installed

This household saw substantial benefits from their renovation. The family of five reduced their winter power bills by 23%, from 4,090kWh to 3,160kWh. Their annual reticulated energy use reduced by 30% to 5,600kWh per year.

The solar water heater provided 70% of the family’s hot water – in winter! During May-September almost all the energy for water heating was being supplied by the wetback and solar connections (reticulated energy for water heating dropped from 2,050kWh to 600kWh). Again, this is despite the family enjoying longer showers and using 29% more hot water in winter.

Inside the house, the family enjoyed much warmer, healthier living. The average winter temperatures in the family room rose by 1.4°C and in the bedroom by 2°C. A heat transfer system is the next step, to spread the warmth from the living areas to the bedrooms. The family say they have had “A lot less colds; kids always had runny noses, less colds and flu”.

The family found the extractor fans in the bathroom and laundry to be “excellent”, especially when combined with new windows. The dampness went from the main living areas and, with everyone using the fan in the shower, from the bathrooms. The family's dehumidifiers were no longer needed.

The renovation kickstarted changes the family had planned to address cold, damp and mould. They appreciated the new warmth of the house, which they attributed to the combination of heating and insulation, but found the cost savings associated with reduced energy consumption a very real benefit.

An unexpected benefit was the very considerable cost reductions they were able to achieve with solar water heating and the wetback. The family was originally sceptical about solar water heating but would now place solar water heating at the top of their priority list. With their water costing less to heat, they no longer worried about their hot water use - “As the family have grown we don’t have to worry about the water – we used to boil water on the fire and share the bath with the kids”.

Even better has been the sense of family well-being the changes have brought. They all felt more relaxed, and being warmer makes them happier. Prior to the renovation, they “were on edge before, and cold, it was a nightmare, this has taken a weight off us”

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