Rinnai vs Dux: Which Heat Pump Is Better? (2026)
Quick Verdict
Dux is the more efficient choice with a higher COP rating, meaning lower running costs over time.
Side-by-Side Comparison
| Feature | Rinnai | Dux |
|---|---|---|
| Price range (installed) | $3,350 - $6,000 | $3,300 - $3,850Lower |
| COP (efficiency) | 3.9 | 4.7Higher |
| Tank warranty | 7 years | 7 years |
| Compressor warranty | 5 yearsLonger | 3 years |
| Noise level | 45dB | Not published |
| Annual running cost | ~$304/yr | ~$252/yrLower |
| Refrigerant type | R134a | R134a |
| Country of manufacture | Japan/Australia | Australia |
| Australian made | No | Yes |
| Best for | Homeowners wanting a trusted household name with the best installer availability and an Australian-made option | Victorian households chasing the higher locally made rebate tier, and anyone who wants an Australian-built tank |
Price Comparison
Rinnai starts from $3,350 installed (before rebates), while Dux starts from $3,300. That is a difference of roughly $50 at the entry level. Dux is the more budget-friendly option upfront, though Rinnai may deliver savings through lower running costs over time. Both prices are for fully installed systems before government rebates and STCs, which can reduce the out-of-pocket cost by $1,000 to $3,000 depending on your state.
Efficiency Comparison
COP (Coefficient of Performance) is the key efficiency metric for heat pumps. A higher COP means more heat output per unit of electricity consumed. Rinnai achieves a COP of 3.9, while Dux reaches 4.7. The Dux is 21% more efficient, which translates to roughly $52 less per year in running costs. Over a 10-year lifespan, that efficiency advantage adds up to approximately $520 in savings.
Warranty Comparison
Rinnai offers a 7-year tank warranty and 5-year compressor warranty. Dux offers a 7-year tank warranty and 3-year compressor warranty. Both brands offer the same tank warranty length, so warranty coverage is comparable.
Noise Comparison
Noise is an important consideration, especially for suburban installations where the unit may be close to bedrooms or neighbouring properties. Rinnai publishes 45dB for its quietest model, and Dux publishes none either. Makers measure sound level at different distances, and one of these two does not publish a figure at all, so ask the installer for the model's data sheet before you compare them on noise.
Climate Suitability
The type of refrigerant a heat pump uses significantly affects its performance in cold weather. Rinnai uses R134a refrigerant, while Dux uses R134a. Both units use the same refrigerant type, so cold-weather performance should be comparable. R134a performs well in moderate climates but may lose some efficiency in very cold conditions.
Pros and Cons
Rinnai
Pros
- Australia's most trusted hot water brand
- AR Series is Australian-made (higher VIC rebate)
- Widest installer network in Australia
- 340L is largest integrated residential heat pump in Australia
- Smooth transition path from Rinnai gas
Cons
- Not the most efficient COP vs CO2 brands
- Only AR Series is Australian-made
- E-Series has shorter warranty
- Standard R134a refrigerant
Dux
Pros
- The Ecosmart DHC range is designed and manufactured in Australia
- On the Solar Victoria locally made list, so it earns the higher Victorian rebate tier
- 7-year tank warranty
- Y-class commercial enamel tank with dual anodes
- Published COP of 4.63 on the 285L
Cons
- Dux publishes no sound level for any Ecosmart model, so you cannot compare it on noise
- Only 3 years on the heat pump components, and 1 year on everything else
- The Pro-Series makes no Australian-made claim and is not on the locally made list
- The model sold as 300DHC25 holds 285L, not 300L
- No minimum operating temperature published for the DHC range
Which Should You Choose?
Choose Rinnai if...
- Homeowners wanting a trusted household name with the best installer availability and an Australian-made option
Choose Dux if...
- You want a lower upfront cost (from $3,300 vs $3,350)
- You want the best efficiency and lowest running costs (COP 4.7 vs 3.9)
- You want lower annual running costs (~$252/yr vs ~$304/yr)
Buying in Victoria? Stack up to $2,700 in rebates
Whichever brand you pick, Victorian households can stack the Solar Victoria Hot Water Rebate ($1,000-$1,400), the Victorian Energy Upgrades discount ($500-$2,000), and federal STCs ($500-$1,200) ahead of the 1 March 2027 gas ban deadline. Rinnai has models on Solar Victoria's locally made list, which qualify for the higher $1,400 tier.
Heat pump guides
- Every Australian heat pump rebate, with the dated changes
- The best heat pump hot water brands in Australia
- Heat pump hot water cost in Australia
- Victoria heat pump rebates
- New South Wales heat pump rebates
- Queensland heat pump rebates
- South Australia heat pump rebates
- Australian Capital Territory heat pump rebates
- Western Australia heat pump rebates
- Tasmania heat pump rebates
- Northern Territory heat pump rebates
What are you replacing?
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