Gridly
IMPORTANT: This product is discontinued in Australia
The Stiebel Eltron WWK 302 is no longer in active supply to the Australian market. As with the WWK 222, any units available are from existing retailer stock. Manufacturer parts support, service pathways, and warranty backing are at risk following discontinuation.
This review exists to document the product for buyers researching it from existing installations or retailer listings - not to recommend it as a new purchase. See alternatives at the bottom if you are actively selecting a heat pump.
COP 3.58: the worst in market
The WWK 302’s COP of 3.58 is the lowest of any heat pump water heater available in Australia - measured under the European EN 16147 test standard. Even accounting for test methodology differences (EN 16147 tests at lower ambient temperatures than the Australian AS/NZS 5125.1), the WWK 302 sits below all current R290 and CO2 competitors on efficiency.
For a household of 3–4 people:
- WWK 302 at COP 3.58: approximately 1,200–1,500kWh/year
- iStore 270L at COP 4.82: approximately 850–1,050kWh/year
- Difference: approximately 350–450kWh/year
- At 35c/kWh: approximately $120–$158/year additional running cost
Over a 10-year product life, that is $1,200–$1,580 more in electricity costs compared to a current-generation R290 competitor - before factoring in the reliability risk documented below.
ProductReview: 2.2/5
The same 2.2/5 rating from ProductReview.com.au applies to the entire WWK range. For the WWK 302:
- Multiple users document units failing within 1 year of warranty expiry (year 5–6)
- Compressor failure is the primary documented failure mode
- Replacement compressor costs have been reported as exceeding half the new unit price
- Regional service technician availability is limited in many areas of Australia, and worsens post-discontinuation
A 2-year compressor warranty on a 302L unit costing $4,000+ represents the weakest warranty-to-price ratio in the market. Competing products at similar prices offer 5–6 year compressor cover.
R134a at this scale
At 302L, the system refrigerant charge is larger than on a 222L unit. The R134a GWP of 1,430 is the highest of any residential heat pump in Australia, and the larger charge amplifies environmental impact in any leak event. Future re-gas costs carry increasing uncertainty as HFC phase-down progresses.
Alternatives for 300L+ indoor installation
If you genuinely need 300L+ in an indoor location:
- Sanden 250L or 315L CO2 split: Tank inside, compressor outside. Requires refrigerant line run but tanks can be positioned in most indoor locations. No backup element but -10°C rated. Better solution than the WWK 302 in almost all indoor scenarios where an external wall or ventilated space is accessible.
- Reclaim 315L CO2: Same indoor-tank / outdoor-unit approach. Australian-made. -10°C rated.
- Ducted arrangement for R290 all-in-one: Some all-in-one units can be ducted - consult your installer about whether the WWK 302’s indoor position could instead accommodate a ducted iStore or similar product.
Before accepting that an indoor all-in-one is the only solution, get a plumber’s assessment of whether a split system (compressor outside, tank inside) is achievable at your property. In most cases it is.
