Hot-water use and running costs in Greater Brisbane

HotWaterWise supports Brisbane City, Moreton Bay City, Logan City, Ipswich City and Redland City. The same disclosed planning rates apply across these five councils. They are starting assumptions, not current retailer offers or measured council averages.

A postcode helps identify the supported council area. Some postcodes need an explicit region confirmation; unsupported locations do not receive a guessed Brisbane result. The calculator explains when more location information is needed.

Record the number of people, shower duration and flow, baths and kitchen use. Check whether the dishwasher and washing machine actually connect to hot water. An appliance that heats its own cold supply does not draw that water from the household hot-water system. YourHome explains these end uses.

The Household Usage calculator combines these answers. Its “Not sure” appliance option includes an assumed contribution and labels the uncertainty. Confirm the connection when possible. A water-efficiency label can help with flow or consumption, but does not by itself establish the hot-water connection.

Litres flowing from a shower are mixed hot and cold water. HotWaterWise converts end uses to an equivalent volume at 60°C, rounds each end use to whole litres and then sums them. That common basis lets the cost calculators compare systems. It is not a suggested shower temperature or a measured tank withdrawal.

Consider an illustrative household using 150 litres per day on the 60°C-equivalent basis. With the accepted 21°C inlet assumption, the temperature rise is 39°C. The annual useful heat is 150 × 4.186 × 39 × 365 ÷ 3,600 = 2,482.82125 kWh, or about 2,483 kWh.

For electric storage, the planning efficiency is 0.90. Purchased energy is therefore about 2,759 kWh a year. At the internal general-electricity assumption of 28.5 cents/kWh, the Hot Water Cost calculator displays $786 a year and $66 a month. It calculates with unrounded energy before rounding the displayed costs. Multiplying the rounded monthly figure by twelve will not reproduce the annual figure exactly.

This is an example, not typical consumption for a Brisbane household. The 150 litres can be replaced by the household estimate and the rate by the relevant bill rate. The result covers modelled hot-water energy, not the entire electricity account, water charges or maintenance.

Find the usage charge in cents per kilowatt-hour for electricity, or cents per megajoule for mains gas. Keep a daily supply charge separate. A controlled-load line may apply to the water heater while the general rate applies to other appliances. Ask the retailer to identify the line if the bill is unclear.

For bottled gas, use the 45 kg LPG guide rather than converting a mains-gas rate. For a household with solar panels, read the circuit and tariff checklist. Rooftop-PV self-consumption receives no numerical credit in these estimates.

Submit a realistic usage estimate, carry it to Hot Water Cost, then review the system and rates before calculating. Submitted details travel between calculators; the result still needs a fresh calculation at the destination.

Cold-water temperature, habits and system performance vary. The reference temperature is not a daily weather model. Compare a lower and higher plausible demand when habits are uncertain. If the next decision is replacement, the heat-pump value guide explains how running costs differ from payback. The complete equations and exclusions remain in Methodology.