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Week Eight - Dial Down The Heat

Turn down the heater 3 degrees to save 111 kilograms CO2e per person per year

· Weekly experiments

My preschooler

- Mummy, I have a good idea. If Shadow's too cold to jump into bed, we can get a dog lift.


- Perhaps we'd save more power by turning the heater back on?

Dog elevator

Won't somebody think of the dogs?

This has been a week of surprises.

Last Sunday, I turned the gas central heating off. I expected ear-splitting tantrums from my preschooler. She didn't even notice.

I thought I'd freeze on the days I worked from home, but I stayed comfortable with a layer of thermals under my usual outfit. We snuggled under a doona in front of TV at night, which we do anyway in winter.

The only one to suffer was the dog. By the week's end, our elderly kelpie was having strange shuddering fits and refusing food. I rushed her to the vet. $266 later, the vet concluded that the dog's arthritis was playing up. I turned the heater back on.

Statistics say we can't all be better than average

I had another surprise when I compared our typical usage with the average. We're conscious of power, we have good insulation and we don't spend hours in the shower. I knew we were greener than most. It turns out I was wrong.

When I compared our winter usage with the average three-person household in my suburb using this handy tool, I discovered that we're about average on electricity and above average on gas. It's a great idea to gauge your own power use. We definitely have room for improvement.

Winter's day - frost and hail

Frost, mist and hail - a good week to turn the heater off.

How much CO2e did I save?

This week, I turned the gas central heating off for five days and ran it at 13 degrees for the remaining two. I also used a small electric heater in my preschooler's room overnight, which we usually do in winter.

The experiment slashed our carbon dioxide and equivalent emissions (CO2e). Emissions from gas dropped by over 80%. That's no surprise to those who claim that every extra degree on the thermostat adds 10% to your energy usage (and your bill).

Interestingly, our electricity emissions also dropped, even though we didn't consciously cut back. I tracked electricity - there's no point saving gas if you start having long, hot showers to make up for it - but I wasn't expecting any change. It dropped by 20%.

If we stuck to this regime for the whole winter, we'd save around a tonne of CO2e from gas and another 300 kilograms from electricity.

Green Virtue versus the Rebound Hypothesis

I can only explain our cuts on electricity with what I'll label 'Green Virtue' and what my grandmother would have called prudence. UK carbon economist, Chris Goodall, has described the same phenomenon. Goodall says 'energy saving begets energy saving'. Like most British households, Goodall noticed that his family's energy usage had been gently drifting upwards over the past decade as they got used to higher and higher internal temperatures. As soon as he installed solar panels, their consumption dropped.

Solar panels change the source of power, but they shouldn't affect the amount used. But according to those in the solar industry, they often do. The mere act of trying to reduce emissions leads to reduced overall consumption by triggering dozens of unnoticed, painless decisions. People turn off lights they're not using. They set the heater one degree cooler. They take shorter showers.

Green Virtue is a powerful force in areas where social norms have set our standards higher than we need for actual comfort. Frankly, this is much of modern life. Unfortunately, a competing factor called the 'Rebound Hypothesis' works in the opposite direction. Improved energy efficiency makes it cheaper to use more fossil fuel and thus cancels out any savings. You may have witnessed this directly. A house or office installs better insulation and immediately sets the temperature higher during winter because it's cheaper to run. They end up using as much energy as they used before they installed the insulation.

This is why technology alone cannot save us from climate change. We also need to change our behaviour.

What's the right temperature?

Every household has a different comfort point, and sick or older family members may genuinely need more warmth. I don't recommend anyone in Canberra permanently dismantle their heater.

Long-term, we've decided to set it to 14 degrees during the day and 10 degrees overnight. It's a lot cooler than many might find comfortable, but it works for us. We used to run the heater at 14 degrees years ago, but like Goodall, our thermostat gradually crept up. Turning it off was a great way to recalibrate.

If you're not sure what a reasonable temperature is, try dropping your heater down three degrees. Leave it there for a week and see if you adjust. You may be surprised at what you find comfortable with an extra layer of clothing. If your family is running around in T-shirts mid-winter, you're doing it wrong.

Dog wearing coat and beanie

An extra layer of clothing makes a surprising difference.

Factoring in my trip to the vet, Week Eight didn't save money, although it might long-term. It did lead to a drastic CO2e cut that's easy to maintain, provided I can make my dogs see reason.

Spreadsheet calculations, data sources and references in 'Notes' section, Week Eight.


Author's note: My 12 1/2 year old kelpie wasn't suffering from the cold that week. She had an unrelated neurological illness and died a month later. We were heartbroken but we're ok now.