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Short answer: most homes moving from gas to a heat-pump hot water system land on 270–315 L storage. Smaller households with light use can be comfortable at 160–200 L if the unit can run during the day, while bigger families or anyone chasing off-peak tariffs should look at 315–400 L for steady comfort and low running costs. At Too Hot To Handle, we size and install Reclaim, Apricus and iStore systems across those ranges.
Why does cylinder size matter?
Gas is usually instantaneous; it makes hot water on the spot, so you rarely think about storage. Heat-pump hot water stores energy in a tank, then uses a super-efficient compressor to top it back up. That’s why the cylinder size matters.
- Daily demand: A simple planning guide is ~50 L of hot water per person per day with a safety buffer. A 4-person family often lands at 270–315 L.
- Use pattern: Showers back-to-back, a weekend bath, or hot-fill laundry will push you toward the 315–400 L end.
- Tariff or solar strategy:
- Rooftop solar users often prefer a slightly smaller tank that reheats in the middle of the day.
- Off-peak controlled loads suit larger storage, so you can coast through busy mornings and evenings.
Where do the brands fit? In broad strokes:
- Reclaim – known for strong recovery and high set-point temperatures, great when you want a mid-sized tank that behaves like a larger system at the tap.
- Apricus – robust all-rounders with sizes that slot neatly into 160, 270 and 315 L use-cases.
- iStore – popular family picks with straightforward controls and tank sizes that map well to common household patterns.
(We’ll match the brand and size to your usage, space and tariff; the right pairing often matters more than the badge.)
How heat-pump hot water works and why recovery matters
A heat pump moves heat from the air into the tank. Quality units deliver several times more heat than the electricity they consume (high COP), which is why bills drop so sharply after the switch.
Two details steer your tank choice:
1. Recovery window: Will you heat mostly in daylight to use your solar, or on off-peak overnight? Day-only operation often needs more litres so you don’t run short at dinner time.
2. Daily production: Some systems can reheat quickly after a run of showers, letting a 270–315 L tank cover families that once assumed they’d need 400 L.
How the brands help:
- Reclaim units pair well with 270–315 L for 3–5 people who want fast top-ups and hot water ready for the breakfast rush.
- Apricus gives flexible options across 160–315 L, handy for apartments or tight plant areas.
- iStore offers family-friendly setups in 270–315 L with simple scheduling to chase solar or off-peak.
A quick sizing table for your hot water heat pump
| Household | Typical pattern | Good starting size | Brand-fit notes |
|---|---|---|---|
| 1–2 people | Short showers, laundry on cold | 160–200 L | Apricus 160–200 L or compact iStore options. Reclaim also works if you want higher temperature set-points in a small footprint. |
| 3–4 people | Daily showers, dishwasher uses cold, some weekend peaks | 270–315 L | Sweet spot for all three – Reclaim 270/315 for fast recovery; Apricus 270/315 for balanced value; iStore 270/315 for easy scheduling. |
| 5–6 people | Teens, back-to-back showers, occasional bath | 315–400 L | Reclaim 315 often covers this with confident recovery; Apricus or iStore 315–400 L if you’re on strict off-peak. |
| 6–8 people or frequent guests | Morning and evening peaks, baths | 400 L+ | Ask us about larger storage plus smart timing to keep comfort high and bills low. |
If you’re moving from gas instantaneous, remember you’re swapping ‘infinite’ flow for smart storage plus efficient recovery. Size for your peak hour, not just your average day.
‘Will I run out?’ + other common scenarios
- Two long showers and a bath in a row. A 315 L tank with a high-recovery unit (e.g., Reclaim) usually sails through.
- Frosty winter mornings. Colder inlet water means each shower draws slightly more from the tank. 315 L takes the anxiety out of busy mornings.
- Off-peak only. If your hot water runs on a controlled load, larger storage (315–400 L) gives you headroom so you’re not chasing reheats during the day.
Cost, comfort and safety
- Bills: Heat pumps use a fraction of the energy of old electric tanks and often undercut gas. Pair the tank size with solar-midday or off-peak schedules for best savings.
- Comfort: Bigger tanks reduce the risk of the last shower going lukewarm. Prefer a smaller cylinder to save space? Choose a unit with strong recovery and set a smart timer.
- Safety: Tanks typically store around 60 °C then mix down at the tap. We set tempering valves correctly and commission each system so the water is safe and consistent.
Real systems we install all the time
- 160–200 L: Apartments and couples who run the unit on solar between 10 am and 3 pm – often Apricus or compact iStore, with Reclaim as a high-set-point option.
- 270–315 L: The family sweet spot – Reclaim 270/315 for quick reheats, Apricus 270/315 for balanced value, iStore 270/315 for simple scheduling and quiet operation.
- 400 L: Busy households on controlled-load tariffs – we’ll pair larger storage with brand settings that keep bills in check and showers steamy.
FAQs
Do I need to upsize when switching from gas instantaneous? Usually, yes. Storage plus recovery is the new equation. Most families land at 270–315 L to cover peak hours comfortably.
Can a 160 L tank work?
For 1–2 light users, absolutely. Especially if the unit runs in the middle of the day on solar. We’ll check your shower lengths and layout before recommending it.
What brand should I pick – Reclaim, Apricus or iStore?
All three are quality. We match brand to household pattern: Reclaim for quick recovery and higher set-points, Apricus for compact installs and solid value, iStore for family-friendly controls across common sizes.
How loud are heat pumps?
Comparable to a modern split-system outdoor unit. We’ll position the outdoor section to keep bedrooms and neighbours happy.
What if my household grows?
Tank size is hard to change later. If you’re torn, sizing up to 315 L is a safe move; it covers school-holiday guests and winter mornings with ease.
Ready to size it properly?
Book a heat-pump hot water assessment with Too Hot To Handle. We’ll measure your peak-hour demand, check your solar and tariff, and recommend the right tank + heat-pump combo from Reclaim, Apricus or iStore, 160, 270, 315 or 400 L, tailored to your family, space and budget. You’ll get a clear quote and a plan to lower bills without running out of hot water.
