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calculation assumptions

assumptions underlying energy costs and savings

assumptions we make about your energy consumption

We use your current energy use to estimate future costs and savings

The Switchwise calculator uses the usage information you provide on our search form to calculate estimates of the cost of your current electricity and/or gas plan(s) for the next 12 months, assuming no change in prices. The calculator then compares this cost to the cost of a range of plans offered in your suburb by other retailers and any differences in yearly costs are shown as savings or additional costs.

We annualise your energy use where less than 12 months usage data is provided

If on our search form you only tell us your electricity and/ or gas usage for a month or a quarter or other period of less than 12 months we annualise this usage in making our calculations. So if you tell us your usage for a quarter we will multiply that usage by 4 to get an annual figure. Similary, a monthly usage figure would be multiplied by 12 to get an annual figure. If the usage figure you provide is unusually high or low then your annual usage may be over- or under-estimated and the potential savings available may be over- or under-estimated.

Usually a household's energy consumption will change from month to month depending upon the seasons and weather patterns. For example, if you experience unusually hot weather one month it would be normal to expect that your electricity consumption in that month would be higher than normal (assuming you use an air-conditioner or fan to cool down).

We assume you have a single-rate meter if you do not provide detailed usage data

If you are unable to provide detailed usage information (i.e. peak, off-peak and shoulder usage where applicable), either because you do not have your electricity bill or gas bill with you or you are moving into a new home and you are unsure how much energy you are likely to use there, Switchwise can make an estimate of your annual energy consumption. You have the choice of an estimate using your household size and type or an estimate based upon your approximate monthly, quarterly or annual spend. As we are unable to determine the type of electricity meter you would have at your property based upon this limited information we assume you have a single-rate meter where you pay the same rate for all your electricity consumption 24/7. Single rate meters are currently the most common meter type but if you have a different meter such as a two-rate meter, where you have off-peak hot water heating for example, or a time-of-use meter, where you have three daily time intervals which are charged at different rates, you will be quoted rates for a different meter type to the one in your property. However, your newly selected energy supplier will determine your correct meter type and send you as part of your welcome pack the pricing information for that meter type. Remeber that you have a 10 business day cooling-off period to cancel should you be unhappy with the rates provided by your new supplier. Therefore we strongly advise that you take the time to enter usage information from your energy bills into our search form to ensure you get the most accurate quote for your property.

Please note that using the usage estimation options provides estimates only - every household has a different consumption pattern depending upon many factors resulting in unique yearly costs and savings but the usage assumptions we make should provide a good relative ranking of our range of plans from cheapest to most expensive.

assumptions we make about electricity and gas tariffs

Potential savings are estimated on the basis of current tariffs

The costs and savings figures displayed on the search results page are calculated only for the first 12 months and are based upon the usage and other information you tell us. These estimated savings are based upon each relevant retailer's current published tariffs and do not factor in future price changes. Note that energy suppliers do not usually offer fixed price (tariff) contracts; energy providers usually change their prices periodically so you must understand that the tariffs quoted today could change at any point in the future and this might impact the level of savings you could achieve by switching. Unfortunately, we do not have a crystal ball so we cannot make predictions about future price changes or other new offers that might become available and how this might impact costs and savings. We base our calculations upon the information that is available at a point in time. We endeavour to maintain up-to-date tariff and plan information for all of the plans we compare so that you can make the right decision at a particular point in time.

Unless you tell us which energy plan you are on potential savings assume you currently pay standard tariffs

If you don't tell us on our search form which plan(s) you are on with your current energy supplier(s), we make the assumption that you are being charged that supplier's standard (standing offer) rates for your suburb (i.e. without any discounts applied). All costs and savings displayed in our search results will be based upon this assumption. So if you do in fact receive a discount from your current supplier(s) on these standard rates you will need to adjust accordingly the savings figures presented to you on our search results table.

A range of estimated costs and savings is displayed for homes in suburbs with multiple distribution networks

If your home is located in a suburb where there are multiple electricity and/or gas distribution networks, our calculator will estimate costs and savings for all network areas in your suburb. In such a situation our search results table will display a range of costs and savings for each applicable retailer and plan. Upon receipt of your completed application your new energy supplier will confirm which distribution network is applicable to your property and the tariffs that will apply.

A range of estimated costs and savings may be displayed where off-peak usage data is provided

If your home has a two-rate electricity meter to support a dedicated off-peak electricity appliance such as electric hot water or storage heating (also called off-peak controlled load) there might be a range of off-peak tariffs that could apply depending upon the type of appliance you have. When you enter off-peak usage data into our search form our calculator will estimate costs and savings for all relevant off-peak tariffs and our search results table will display a range of costs and savings for each applicable retailer and plan. Upon receipt of your completed application your new electricity supplier will confirm which off-peak tariff is applicable to your property.

There is a slight variation to this rule for Victorian residents, where there are five sets of off-peak controlled load tariffs that can be bundled with the single rate GD/GR tariff as well as a separate 'Winner' time-of-use tariff any which of could apply to your property. When you enter off-peak usage data our calculator will estimate costs and savings across all these six tariff types and display the results as a range. Click on this link to read more about off-peak electricity in Victoria. Upon receipt of your completed application your new electricity supplier will confirm whether one of the five controlled load off-peak tariffs or the time-of-use tariff is applicable to your property.

assumptions we make about discounts and bonuses

We assume you qualify for all discounts and bonuses associated with each plan

We assume you qualify for all discounts and bonuses associated with each plan displayed in our search results table. Clicking on view details for any plan shown in the results table will display all the details of that plan including what has and hasn't been included in the costs and savings calculation.

Each supplier usually offers different discounts, bonuses and other incentives to reduce the amount you pay for your electricity and gas. The most common form of discounting used by energy retailers is to offer pay-on-time discounts, which means that you only receive a discount if you pay your bills before the due date. Some retailers also offer standard discounts, which mean you receive a discount regardless of whether you pay your bills on time. A few suppliers also offer sign-up rebates or bonuses which are credited to your energy bills - usually spread over a couple of billing periods or credited on your next bill after your first 12 months.

The first year cost and savings figures for each electricity or gas plan shown on the Switchwise website are calculated by determining the electricity and/or gas tariffs applicable to your home, multiplying them by your annualised electricity and/or gas consumption and deducting any applicable discounts and first-year bonuses or rebates. The Switchwise calculator assumes that you pay your bills on time.

We assume you will stay with your new supplier for a minimum of 12 months

The Switchwise calculator assumes that you intend to stay with your new supplier for a minimum period of 12 months. It is important to note that any sign-up bonuses or rebates are often one-off amounts and do not occur each year. In other words, you would receive bonuses or rebates only in the first year so the savings you could receive in the second year would be lower by the amount of the bonus. If you are likely to remain with your new supplier for several years then you should take this into account when choosing a new energy supplier and plan.

We do not include gifts and other incentives in the estimated savings figures

The Switchwise calculator does not include the value of benefits given to you as a customer but not credited to your energy bills. Some energy providers might offer cash vouchers for use in their retail shops or to offset the cost of other services they offer. Others might offer free gifts such as a gift card, magazine subscriptions, movie tickets or DVD players. These types of incentives are not included in the cost and savings calculations we make as we believe either that their value is too subjective or that they do not actually reduce the size of your energy bills. However, if such incentives are of benefit to you personally and you value them then you should factor this into your final decision about which supplier and plan to select.


Switchwise is a useful tool to provide a comparison of the costs of a range of energy suppliers and plans available in your suburb. We recommend that you also use other information sources such as energy suppliers' websites to assist you to determine the right supplier and plan for your particular situation.