Property Glossary
The hot water system is one of the largest contributors to household energy costs. Gas, electric resistance, heat pump and solar systems vary significantly in running cost and efficiency. Understanding what a property has — and what it would cost to upgrade — is useful due diligence at any price point.
Hot water heating is typically the second-largest energy cost in a Queensland home after space cooling. Understanding what type of hot water system a property has — and how efficient it is — is a relevant part of both sustainability and running cost assessment.
A gas-fired storage tank heats water using a gas burner and maintains it at temperature. Common in homes built with gas connections. Has lower upfront cost than heat pump systems but ongoing gas bills. As gas prices rise and households shift toward fully electric operation, gas hot water is increasingly viewed as a transition technology rather than a long-term solution.
Heats water on demand with no storage tank — no standing heat losses. More efficient than gas storage on a gas-per-litre basis, but still dependent on ongoing gas supply and gas pricing. Popular for households that want hot water immediately without the cost of maintaining a stored tank temperature.
The least efficient electric option. Uses an electric element — similar to a kettle — to heat stored water. High energy consumption relative to heat pump alternatives. Very common in existing Queensland homes due to low upfront cost. Running costs can be reduced by configuring the system to heat during off-peak periods, but it remains significantly less efficient than a heat pump.
Uses the same principle as a refrigerator in reverse — extracting heat from surrounding air and transferring it to the water. 3 to 4 times more energy-efficient than an electric resistance system. Operates on electricity, making it compatible with solar generation. The preferred hot water solution for fully electric homes in Queensland. Higher upfront cost than electric resistance but significantly lower running costs. Requires adequate outdoor space for the unit and works best in environments with ambient air above about 5°C — well suited to Queensland's climate.
Roof-mounted solar collectors (not solar PV panels) heat water directly using solar radiation, supplemented by an electric or gas booster for periods of low solar irradiance. Effective in Queensland's sunny climate. Requires roof space for collectors separate to any solar PV panels. Reduces hot water energy costs significantly but at higher upfront installation cost.
When assessing a property, the hot water system is worth a few minutes of specific attention:
Identify the hot water system type from a physical inspection — or ask the selling agent directly. The system type determines its efficiency, running costs and how it fits with the property's energy infrastructure. A gas system in a property you intend to fully electrify is an upcoming replacement cost. An electric resistance system in a property with solar is a missed efficiency opportunity.
Most hot water systems have a practical lifespan of 10–15 years. An older system is an upcoming replacement cost that should be factored into your assessment of the property's value and condition. A system that is clearly at or near the end of its life should be reflected in negotiations. Ask the selling agent for any documentation on the system age and service history.
An undersized hot water system for the household's needs leads to running out of hot water — an undersized tank or an underpowered heat pump. Confirm the tank capacity or flow rate is appropriate for the number of occupants.
If the property has an old electric resistance system or an aging gas system, estimate the cost of upgrading to a heat pump water heater. Supply and installation of a quality heat pump hot water system typically costs $3,000–$5,000 — less with available government rebates. This is a relatively modest cost relative to Noosa property values and can be negotiated into the purchase price if the system is clearly aging.
Queensland government incentives — including the Home Energy Upgrades Fund and relevant rebate programs — periodically provide financial assistance for upgrading hot water systems to more efficient alternatives. Confirm current available incentives at the time of purchase.
Noosa's warm, humid subtropical climate is well-suited to heat pump hot water systems — which require ambient air above approximately 5°C to operate effectively. Noosa's minimum temperatures rarely approach this threshold, meaning heat pump systems operate at close to peak efficiency year-round. This is in contrast to cooler parts of Australia where heat pump performance degrades in winter.
The prevalence of solar PV on Noosa homes — and the strong solar irradiance of the Queensland coast — also makes the pairing of solar PV with a heat pump hot water system particularly effective. A smart heat pump controller can be configured to heat water during periods of peak solar generation, effectively using excess solar electricity that would otherwise be exported to the grid at a low feed-in tariff rate. The result is hot water heated essentially for free during sunny days.
Gas hot water systems remain common in established Noosa homes — many properties were built with natural gas connections and have maintained gas hot water systems through successive replacements. The trend toward fully electric homes is gradually changing this — buyers who purchase with sustainability intentions often prioritise replacing gas hot water as part of an overall electrification program.
For the checklist-oriented buyer: in Noosa's market at current energy prices, a heat pump hot water system paired with solar PV is the highest return sustainability investment available after ceiling insulation.