Energy efficient where possible

Transport efficiencies through New Urbanism are one important goal. But so is building energy-efficient homes and offices.

We can now build comfortable low energy apartments that keep us warm in winter and cool in summer, with much lower or even zero air-conditioning bills! Even the materials we use can improve minimise impact on the environment. But let’s start with the design.

First, let’s design our home or office with our local climate in mind.  Most climates can use thermal mass to store an ambient, comfortable temperature, but but how they do so in each climate will vary according to where we live. There are more guidelines here, as I’m not going to analyse all the options but just want to highlight that local considerations are important.

But what is thermal mass in the first place? As the Australian Government website says:

Thermal mass is the ability of a material to absorb and store heat energy. A lot of heat energy is required to change the temperature of high density materials like concrete, bricks and tiles. They are therefore said to have high thermal mass. Lightweight materials such as timber have low thermal mass. Appropriate use of thermal mass throughout your home can make a big difference to comfort and heating and cooling bills.

The graph below shows how the right materials positioned in the right place store the sun’s heat for later that day. Note how the single unbroken line rises and falls with the outside temperature, but a clever building with good heavy, sun-absorbing materials and insulation can keep your home or office building much more comfortable.


So how does it work? There are special plans for different climates. Tropical plans are all about cooling the house, while sub-tropical areas like Sydney have more thermal mass positioned for heating in winter, and cooling in summer. Remember, while these diagrams show individual homes, we’re actually after eco-designed apartments.

Winter stores heat


Summer releases heat


Indeed, the whole Your Home site has more detail about environmentally friendly, energy efficient designs and materials than I want to go into right now.  You can download their free 10 page PDF YOURHOME-2-PassiveDesign-9-ThermalMass-(4Dec13) if you’re planning a renovation or want more detail. It covers glass-to-mass ratios for different climates, building for cool temperate and alpine climates and hot dry climates, positioning, materials, foundations and concrete slab work, where to put the termite barriers and even Phase Change Materials (PCM’s) that absorb heat and then release it later at night. It’s a comprehensive site, and has PDF’s on saving water in the home, materialsenergy, and so on. I highly recommend a good browse and downloading some of their PDF’s for later.

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