1. What energy is actually connected?
This single answer removes most of the options. Homes with reticulated gas can consider gas storage and continuous flow alongside electric options. All-electric homes are choosing between conventional electric storage and a heat pump. Availability varies street by street in parts of Perth, so confirm it for your address rather than assuming.
2. How much hot water does the household need?
Sizing follows occupants, bathrooms and simultaneous use — not the size of the house. A storage system is sized on volume and recovery rate. A continuous flow unit is sized on litres per minute at a given temperature rise, which is what determines how many showers can run at once.
| Household | Storage guide | Continuous flow guide |
|---|---|---|
| 1–2 people, 1 bathroom | Smaller storage volume | Lower flow-rate unit |
| 3–4 people, 1–2 bathrooms | Mid-range storage volume | Mid flow-rate unit |
| 5+ people, 2+ bathrooms | Larger volume or faster recovery | High flow-rate, or two units |
Use the table as orientation only. Actual capacity is confirmed on site against how your household really uses hot water.
3. Where will the unit go?
- Gas units need clearance to windows, openings and boundaries for the flue
- Heat pumps need airflow clearance and a position where fan noise is acceptable
- Storage tanks need a sound, level base and access for future servicing
- Internal installations need a safe tray and a drain point
4. Up-front cost or running cost?
Conventional electric storage is usually the cheapest to install and the most expensive to run. Heat pumps cost more up front and use considerably less electricity. Gas sits between the two, with continuous flow avoiding standing losses from stored water. Which is better depends on how long you will stay in the home and how much hot water you use.
Rebates and incentives for efficient hot water systems change over time and vary by product and household eligibility. Check the current programs applying in Western Australia before assuming a rebate applies.