How much do each of my appliances and electronics cost to run during a price spike?

Note: The estimates on power usage of appliances in this article are just general guides. Every appliance is different and the power consumption of a given device can be affected by several different variables.

The devices and appliances in your home use vastly different amounts of power. That's why some appliances are much more important to shift away from price spikes than others.

We've included some estimates below. If you want to try to estimate the running costs for your own specific devices, you can skip to the bottom of this article which explains the terms used here and how to run calculations like this on your own.

Summary

Shift your usage

• Air-conditioner
• Electric heater
• Electric cooktop
• Electric oven
• Electric vehicle charging
• Dishwasher
• Washing machine
• Electric hot water
• Electric kettle
• Microwave
• Non-essential devices

Continue with normal use

• Electric fans
• Lights
• Fridge
• Television
• Laptops and tablet

Air-conditioner - Shift your usage

Your air conditioner is one of the most energy intensive appliances in your home, and one of the most expensive appliances to run during a price spike. Since price spikes typically happen in the evening, we recommend pre-cooling your home with the air conditioner in the hours before the price spike, then switching off the air-conditioner for an hour or two until the price spike is over (as long as you can keep your home at a safe and comfortable temperature this way).

You can also run ceiling, pedestal and desk fans during a price spike. They use a tiny fraction of the power an air conditioner consumes. You can see how much they'll cost to run during a price spike below.

This CSIRO study of Aussie households found that most air conditioners average around 2kW when running, even when accounting for big differences in rated power consumption. That's partially because more powerful air conditioners typically have a shorter duty cycle - meaning they need to run less often to keep the temperature within the target range.

Air conditioner running cost estimate during a price spike (inc. GST)*

* Assumes a typical 70% duty cycle.

Electric heater - Shift your usage

Electric heating can be highly energy intensive, although some forms of heating are much more efficient than others. When a price spike is forecast for a cold evening, we recommend pre-heating your home in the hours before the price spike, then switching off your electric heater for an hour or two and rugging up with your best winter woollies until the price spike is over (as long as you can keep your home at a safe and comfortable temperature this way).

You may be surprised to learn that although reverse cycle split system air conditioners (A.K.A. heat pumps) are typically larger and more powerful than small portable heaters, they're usually cheaper to run thanks to their super-efficient heating capabilities.

Electric heater running cost estimate during a price spike (inc. GST)*

* Assumes a typical 70% duty cycle.

Electric cooktop - Shift your usage

Running two of your large burners during a price spike can consume as much power as an air conditioner. As price spikes usually occur in the evening, you'll want to shift your dinner prep prior to the price spike if possible. Alternatively, you might decide to prep a meal that doesn't require cooking, like a salad, or go out to a restaurant, or order delivery.

Electric cooktop running cost estimate during a price spike (inc. GST)

Electric vehicle (EV) charging - Shift your usage
In general, we recommend that you only charge your EV during the middle of the day or overnight to make the most of Amber's cheaper and greener pricing. Limiting your EV charging to these times will also help ensure you never charge your EV during a price spike, which could cost you hundreds of dollars. Price spikes are extremely unlikely to occur outside peak times due to lower demand on the grid and higher availability of renewables.

Electric oven - Shift your usage

As with an electric cooktop, electric ovens use a fair amount of power. You'll also want to shift your cooking time before or after the price spike, or sort out an alternative option for dinner that doesn't require the oven.

Electric oven running cost estimate during a price spike (inc. GST)

Dishwasher - Shift your usage

Dishwashers can be expensive to run during a price spike, so it's best to run the dishwasher before the price spike starts, or after it's ended. If you really need to clean a few dishes and utensils during a price spike, hand-washing will be the cheapest option for you.

Dishwasher running cost estimate during a price spike (inc. GST)

Washing machine - Shift your usage

It's a good idea to do your washing earlier or later in the day to avoid paying much higher prices than usual.

Washing machine cost estimate during a price spike (inc. GST)

Electric hot water - Reduce your usage unless on a controlled load tariff

Electric hot water systems operate under a variety of configurations, and your setup will determine whether you'll want to limit your hot water usage during a price spike.

If you have a controlled load tariff at home then you can generally continue using hot water as normal during a price spike. That's because your hot water system typically runs during the middle of the night and will not run during a price spike. If you use hot water during a price spike, it'll come from your pre-existing store of hot water. (If you have a controlled load tariff it will be visible in the Amber app).

If you're not on a controlled load tariff then this means your hot water system will run as needed throughout the day, or may be on a timer. You'll want to reduce your hot water usage during price spikes to minimise the chance that your hot water system heating element switches on during a spike. For example, a price spike is a very expensive time to have a shower.

Electric hot water cost estimate during a price spike (inc. GST)

Electric kettle, 4 minute boil - Shift your usage

Electric kettles use a lot of power, but only for a few minutes. This means having a cup of tea or coffee during a price spike will cost much more than normal, but won't make a big difference to your bill overall. Still, it's best to shift your usage away from the price spike - unless you really need a cuppa!

Electric kettle cost estimate during a price spike (inc. GST)

Microwave - Shift your usage

Like an electric kettle, your microwave uses a lot of power for a brief period of time. It's best to avoid using your microwave during a price spike, or use it for only very brief periods (e.g. 2 - 3 minutes).

Microwave cost estimate during a price spike (inc. GST)

Non-essential devices - Shift your usage

There may be non-essential devices in your home that you can temporarily switch off on days when a price spike is forecast to save on your electricity costs. A few examples include: pool pumps, spas, bar fridges, and wine coolers.

Electric fans - Continue with normal use

Electric funs (such as ceiling fans) are approximately 60x cheaper to run than an air conditioner during a price spike. This means you could run around 60 ceiling fans at the same time for the same amount of power it takes to run one standard air conditioner! For most people, the comfort a fan provides during hot weather will be worth the slight additional cost during a price spike.

Electric fan cost estimate during a price spike (inc. GST)

Lights - Continue with normal use

You can continue with normal use of your lights during a price spike, although LED and incandescent bulbs are much cheaper to run than inefficient halogen bulbs.

Light bulbs cost estimate during a price spike (inc. GST)

Fridge - Continue with normal use

Modern fridges are highly energy efficient, needing to run only around 1/3rd of the time while the fridge's sealing and insulation do most of the work to keep things cold inside. There's no need to unplug the fridge during a price spike. 

* Assumes a typical 33% duty cycle.

Television - Continue with normal use

LED TVs are highly energy efficient and can continue to be used during price spikes without making a noticeable impact on your bill.

LED TV cost estimate during a price spike (inc. GST)

Computer - Continue with normal use of tablets and laptops

Tablets and laptops are relatively cheap to charge during a price spike if you need, although you can save even more by charging your electronics in advance of higher prices. It will be much more expensive than usual to run a full desktop PC and monitor setup, particularly one that is high-powered, so it's best to shift usage of higher-powered setups earlier or later in the day if you want to reduce your costs as much as possible.

How to run the numbers for a specific device or appliance

First, a bit of jargon - a kilowatt hour (kWh) is the amount of energy consumed by a 1,000 watt (or 1 kilowatt) appliance running for 1 hour.

You can calculate the power consumption - and therefore the cost - of your specific appliances per hour if you know the following.

1. Appliance kW usage (if stated in watts, divide by 1,000). The power consumption of your appliances is typically stated on a sticker on the appliance, or in the user manual.
2. Current wholesale price (30 minute live price in the Amber app).

Here is a formula you can use:
Appliance kW * Wholesale price = approx. cost to run for one hour OR
Appliance wattage / 1000 * Wholesale price = approx. cost to run for one hour

For example, a 1kW appliance running for 1 hour when the wholesale price is $19 will cost $19 to run. (1kW * $19 = $19 per hour).