How much does AC add to your energy bill each year?

Across Australia heating and cooling makes up an average of 40% of household energy consumption. The costs that this generates on your energy bill will depend on a number of factors including:

• the size, condition and age of your air conditioning unit
• the size of the space you are trying to cool
• the brand (some units are designed around energy efficiency)
• how regularly you turn the unit on
• which state you reside in and thereby your climate
• at what temperature you operate the system and how long for
• which electricity provider you are signed up to.

States and territories such as Queensland and NSW generally have warmer summers than Victoria, the ACT and Tasmania so the costs of running air conditioning is likely to be higher in these states.

The average number of days exceeding 28 degrees in recent years has been roughly 169 days in Brisbane, 66 in Sydney, 55 in Melbourne, and 97 in Adelaide.

These are days when we are most likely to switch on our air conditioning system to control the temperature in our homes. The hotter it is, the more energy we tend to use and the more likely we are to be struck with a hefty bill.

There is also peoples’ tolerance of heat and cold to take into account – some may prefer the warmer weather and use the unit more in winter or vice versa.

Cooling costs

On average, cooling a room costs more than warming it, which will be reflected on your energy bill.

For split systems, depending on the size of the room you are trying to cool an average reverse cycle air conditioner could set you back around $0.25 – $0.35 per hour to run. Moving up to a medium sized room, say a master bedroom, might run at $0.36 – $0.70 per hour. A larger area such as a 50sqm lounge could cost between $0.70 and $0.95 per hour. At first glance these charges don’t seem like much. But, added up over peak periods, they can translate to hundreds of dollars a year.

When we factor in air conditioner size and how much running costs for the year (say, 3 months of summer) the figures look a lot higher:

There are of course difference factors that can further affect the cost of running your system. For example:

• the difference between running a 15-year-old split system and a newer model can range between $57 to $166 per year.
• Some brands and models are more energy efficient than other
• Some systems are more energy efficient, for example inverter split systems.

Making sure your system is in good shape with regular services can assist in your air conditioning unit working efficiently and thereby not adding to your utility bills. You may also have access to concessions that bring your energy costs down.

For ducted systems, in terms of system energy usage, ducted reverse cycle air conditioning systems cost more to run. At a rate of between $1.45 – $2.12 per hour you can expect to pay around $1,000 for the luxury of using this type of system during summer. However, these costs can be offset with a reasonably priced energy provider or access to your own renewable energy system.

Heating costs

For split system, the good news is that the average reverse cycle air conditioners are quite cost efficient, at around $0.13 – $0.36 per hour, for heating purposes.

Other types of heating such as electric radiant heaters cost around $0.36 per hour, as with an electric panel heater at $0.43 and a gas heater at $0.43 – $0.51 per hour. Portable heaters are less efficient as they heat a smaller area.

With heating you can reduce utility costs by:

• Maintaining your unit
• Closing the blinds in the area you are heating
• Wear a jumper rather than turning the heater on full blast
• Making sure doors and windows are closed to keep the heat in
• Using a unit appropriate to the size you need to heat.

It is worth noting that compared to other appliances, an air conditioning system, even one that has been well looked after, generally seems more expensive because we use them over longer periods of time. However, other appliances can cost more per hour to run. For example running your microwave costs $0.28 – $0.53 each hour withclothes dryers starting at $0.50 and typically costing anything up to $3.14 per hour to run. Comparatively cooling or heating your space via air conditioning may cost less to run, but it all adds up.

Increasing cost efficiency

It’s good to be mindful of what air conditioning can add to our energy expenditure so as not to be surprised by higher bills in summer. We can utilise this knowledge to be more efficient; dressing appropriately for the weather, using smart devices to cool or warm the house moderately rather than all at once while using a lot of power.

Each degree we add or minus in temperature while heating in winter or cooling in summer increases our energy consumption by about 5–10%.

In most Australian climates, setting our thermostats to 25 degrees for cooling in summer, and around 20 degrees for heating in winter should provide enough comfort while keeping high bills at bay.

If you are still concerned about how much your air conditioning bill adds to your utility costs each year it may be time to consider updating your unit to a more energy efficient one, looking for a more reasonably priced energy provider or considering an alternate source of power such as renewable energy. There are many ways you can reduce costs without compromising your comfort.