What to note down
- How many people live in the home, and whether that's likely to change soon.
- How many showers or baths tend to run back to back, especially in the morning rush.
- Whether your current system ever runs out of hot water, and at what time of day.
- Which kind of system you're leaning towards: a storage tank heated by gas, electricity, a heat pump or the sun, or a continuous flow unit that heats water as it passes through.
- What you have now. The label on your current unit usually shows the brand, the model and when it went in, so take a photo of it.
How to use your answers
Treat your notes as the start of a conversation, not an order. Headcount is only part of it: the type of system, how close together your showers are and where the unit will sit all change the right size.
Send the plumber your notes with a photo of your current unit's label. If your old system never ran out, say so; that's useful information too.
Size limits that affect discounts
For STCs, the federal certificates that can lower the price, an air source heat pump must be under 425 L and a solar water heater under 700 L. The model also has to be on the register. If you're counting on a discount, check the model before settling on a size. STCs explained has more.
Questions to ask the plumber about size
- Does this size cover how many of us shower in the morning?
- Will a bigger tank fit where the old one stands, or does it need to move?
- Is this model on the STC register?
- Would a different type of system change the size I need?
Once your notes are ready, we match you with a plumber who specialises in hot water to check the size against your house.