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Getting rid of old, energy-inefficient homes and replacing them with new, greener ones may seem a logical step to reduce greenhouse emissions and energy use - but not always so, finds a new study.
Instead of tearing down your older home and building from the ground up, your humble abode can be given an eco make-over that not only makes sense based on time, cost and resources, but "can also lead to reduced energy use in buildings in both the short and long term," said Anne Power, from London's Sustainable Development Commission in the UK, author of the study.
However, homes that are badly dilapidated should be demolished, the study indicates.
Demolishing the poorest and oldest of homes to improve the efficiency of housing is a trend quickly gaining ground in Europe, she said, but "work on refurbishment shows that existing homes, often in brick-built terraces, are relatively easy to upgrade and, with careful reinvestment in the existing buildings, can achieve as high environmental efficiency standards as current new build[ings]."
Germany has used this strategy successfully, reducing energy use in many homes by 80 per cent, and cutting carbon dioxide emissions significantly, by upgrading rather than levelling older housing.
Powers describes a range of environmental, social and economic benefits in favour of renovating. Refurbishing an existing house instead of rebuilding an entire new one, she said, requires fewer materials be manufactured and transported, and reduces the amount of waste dumped in precious landfill space.
Building materials and processes are highly energy intensive, and new homes can use four to eight times more resources than an equivalent renovation. So building anew with new materials, however good the long-run energy efficiency of the building in use, has major energy, carbon and…environmental impacts, Power said.
Environmental architect Dick Clarke, from Envirotecture in Sydney agrees with the finding, but cautions that a number of variables should be factored in, such as the value of raw materials, the structural condition of the building and the adaptability of the layout and orientation.
"Some buildings lend themselves to renovation, some do not. It is important to make that call correctly, so a good building is not wasted, or on the other hand, an opportunity to start again is not hampered," he said.
When a building is deemed suitable for renovation, it's not just the environment that benefits; it is also a great option for preserving cultural character and continuity in an area, Clarke said.
Something old, something new
But can a renovated old home ever be as energy efficient as a sparkling new one? "It really depends upon the base building - if its fundamentals are right, or can be made right with little rebuilding, then it is already ahead of the new building and heading in the right direction."
In the UK at least, the Royal Commission on Environment Pollution have estimated that refurbished homes can perform, over a 60-year period, just as well as new homes built to current standards. And over a shorter term of 10 years, they save more carbon emissions and energy use than new counterparts.
But before we all get renovation-happy, Kirsty Máté, head of the Interior Architecture Program at the University of New South Wales in Sydney, warns against unnecessary renovations, particularly when it comes to internal fit-outs.
"Kitchens and bathrooms are the most renovated spaces in homes and can be changed every seven years…This not only creates a lot of waste and use of resources, but could also result in high energy consumption.
"There is evidence…that in commercial buildings where the rate of change and amount of materials used is very high, the embodied energy of all of this stuff churned on a regular basis is greater over the life of the building than the operational energy," Máté said.
- Fixing your home's orientation: Get the living areas into or out of the sun, depending upon where [your house] is on this big island continent. Get the kind breezes in, keep all harsh sun and winds out.
- Zoning off internal spaces: Separate living from bedrooms and utilities.
- Using thermal mass to store warmth and "coolth" (that's materials able to absorb the heat or cold, like concrete, brick and sandstone, which help you cut down on use of energy-guzzling heaters or air conditioners.)
- Making use of insulation: Add the right insulation for [your] topography and climate zone - pick off the worst problem (heat or cold) first.
- Using ventilation: All Aussie houses need it, like a shearer needs a beer.
- Getting glazing: Use thermally efficient glazing so the rest of your hard work doesn't go out the window. Double glazing older, sound windows in-situ is both possible and very cost-effective.