Understanding the energy rating system for appliances

Energy ratings aren’t as simple as ‘five-star is good and one-star is bad’. We explain how to understand them better to help you save energy.

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8 min read
Household appliances can use more energy than you’d expect. Learning how to purchase the most energy-efficient appliances is key, which ones may be using more power than they’re actually worth and cost you more in the long run.

As a sustainability consultant and energy auditor, Graeme Ambrose of Ecodecisions in Victoria works with residential and commercial customers to help them reduce their energy usage and running costs.

While there are always some relatively predictable energy drains, one home – in particular – stands out for him.

“When I work with any home or business, I always start by looking at their bills and the graphs. That way I can get a sense of how much energy they are using and where the peaks are,” he says.

“This particular house was regularly pulling 16kWh hours a day, and all of a sudden it went up to 23kWh hours a day.

“Six-kilowatt hours a day was the family’s old fridge, and I accounted for the other 10, but I couldn’t work out where the extra seven kilowatt hours came from. I went for another walk around the house, and eventually found the culprit.

“The eldest son had built this big gaming computer where the power supply was rated in amps, not watts.” Because amps and watts are different measures of energy use and consumption in amps looks much lower than it would in watts, the high consumption of the system had slipped under the radar – an extra 7kWh a day.

“Their energy use – and bill – went up nearly 50% because of that. It was costing them an extra $890 per year,” Ambrose says.

“It’s very common for teenagers to have these gaming machines. They spend all day on them, and it just chews the energy, but people don’t realise just how much they impact your energy bills.”

Understanding energy star ratings

For most of us, the biggest users of energy in our homes (aside from the big game consoles) are our home appliances – TVs, washing machines, air-conditioners, fridges and freezers. And we’re all accustomed to seeing their energy star ratings.

The more stars, the more energy efficient the product is, right?

Well, sort of.

“For a start, the star rating has changed three times in the last 12 years, as appliances get more and more efficient,” says Ambrose. “So, a product that was rated five stars six years ago wouldn’t get five stars today.”

Choosing new appliances by energy star rating

Rather than looking at the stars when purchasing new appliances, Ambrose advises looking at the bar in the centre of the sticker.

Look carefully, and you’ll see a number – that’s the number of kilowatt hours or units of energy per year that appliance will use when new, based on standard uses.

Take note of the kWh per year in the middle of the sticker and then multiply it by your current kWh rate on your bill. For example, if your kWh rate was $0.33, and your washing machine uses 380 kWh per year, you might spend approximately $125.4 on running that appliance per year – depending on whether you were using it during peak or off-peak times of the day.

And this is important because the energy star system only compares similar appliances – TVs of the same size, for example, rather than all TVs.

“Look at the kWh per year in the middle of the sticker and then multiply it by your current kWh rate on your bill.”

“I recently bought a new fridge freezer, and compared a couple of five-star models,” Ambrose explains.

“One was 550 litres and would use 450-kilowatt hours a year. The other was 450 litres and would use 300-kilowatt hours a year.

“Both were rated five stars, one was 100 litres smaller than the other, but one would use 50% more energy – and cost me 50% more per year to run!”

It’s always a good idea to keep the energy sticker on products to refer back to and remember that the energy efficiency rating applied as new.

“Energy efficiency of fridge/freezers will decrease by around 3% per year. The seals harden so it tends to leak, the compressor motor wears out, bearings get worn – a whole lot of things eventually mean the fridge runs a lot less efficiently than when it was new.”

In some cases buying a new, more efficient product will save you more money than persevering with something old.

Other common energy drains in the home

Continuing the fridge theme, beer fridges are typically a huge consumer of energy. Often, a new fridge for the kitchen will mean a new beer fridge for the garage.

Bad move.

“It costs so much to run an old fridge in a hot garage. In fact, I once worked out that one bloke’s beer fridge was costing him the equivalent of 35 slabs of beer each year! That was the end of that fridge.”

Pool pumps, air conditioners and hot water systems also have high running costs.

“Another is those little fan heaters,” says Ambrose, explaining that a small fan heater running for seven hours uses 16kWh – more energy than the average four-person domestic house uses in a day.

Another unseen source of energy use is washing machines that only go to standby – and don’t turn off entirely unless you flick the switch at the mains.

Some appear to be turned off, Ambrose explains, but are only on standby, with no light to indicate it.

“People are often furious when they find this out. It will cost them around $13 per year. Now, while it may not be much in the grand scheme of things, it all adds up, and it’s $13 that should be in your pocket.”

You can buy usage monitors to identify which devices are still drawing power, or use smart powerboards to cut off standby power. But just turning off the powerpoint at the wall makes sure any appliance isn’t drawing standby power.

Understand your bills to get energy savvy

The best thing people can do to understand their energy usage, says Ambrose, is to learn how to read their energy bills.

“Don’t look at the dollar values because that will tell you very little,” he says. “Look at how many cents per kilowatt hour you’re paying, and look at the graph to see what’s happening with your energy usage.

“If it’s spiking around May, June and July, then you’re using a lot in heating. If you’re spiking in December, January and February, then you’re using a lot in cooling. The rest of the appliances should stay fairly common or fairly flat.”

If you notice any spikes or any consistent increase in usage, then take a look around.

And if you have a teenager (or a teenager at heart) in your home, maybe start your search in the places they hang out.

Get in tune with your energy usage

Using smart meter data and clever algorithms, Energy Insights estimates how much electricity your home uses on heating, cooling, lighting, laundry, standby and more. You have greater visibility of your electricity usage and can take control of running costs to find out where you could start saving.

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