Rinnai vs Stiebel Eltron: Which Hot Water Heat Pump Is Better? (2026)
Quick Verdict
Rinnai is the more efficient choice with a higher COP rating, meaning lower running costs over time.
Side-by-Side Comparison
| Feature | Rinnai | Stiebel Eltron |
|---|---|---|
| Price range (installed) | $6,500 - $9,500Lower | $7,300 - $9,500 |
| COP (efficiency) | 4Higher | 3.8 |
| Tank warranty | 7 yearsLonger | 5 years |
| Compressor warranty | 5 years | 5 years |
| Noise level | 45dB | 44dBQuieter |
| Annual running cost | ~$300/yr | ~$250/yrLower |
| Refrigerant type | R134a | R134a |
| Country | Japan / New Zealand | Germany |
| New Zealand brand | No | No |
| Best for | Households wanting a well-supported mid-range option, especially larger families needing 275-340L capacity | Buyers who value German engineering and want a proven integrated unit with direct manufacturer support |
Specifications and pricing are indicative for the NZ market as at June 2026. Confirm current models and exact pricing with your installer.
Price Comparison
Rinnai starts from $6,500 installed (indicative, June 2026), while Stiebel Eltron starts from $7,300. That is a difference of roughly $800 at the entry level. Rinnai is the more budget-friendly option upfront, though Stiebel Eltron may deliver savings through lower running costs over time. Both prices are full installed prices in NZD including GST. There are no government rebates for hot water heat pumps in New Zealand, so the quote you receive is the price you pay.
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 4, while Stiebel Eltron reaches 3.8. The Rinnai is 5% more efficient, which translates to roughly $50 less per year in running costs. Over a 10-year lifespan, that efficiency advantage adds up to approximately $500 in savings.
Warranty Comparison
Rinnai offers a 7-year tank warranty and 5-year compressor warranty. Stiebel Eltron offers a 5-year tank warranty and 5-year compressor warranty. The Rinnai has the stronger warranty coverage with 7 years on the tank, giving you 2 extra years of protection compared to the Stiebel Eltron. A longer tank warranty can provide significant peace of mind, as the tank is the most expensive component to replace.
Noise Comparison
Noise is an important consideration, especially for suburban installations where the unit may be close to bedrooms or neighbouring properties. Rinnai operates at 45dB, while Stiebel Eltron runs at 44dB. The Stiebel Eltron is quieter at 44dB. At this level, it is similar to a quiet office and should be unnoticeable from inside most homes.
Climate Suitability
The type of refrigerant a heat pump uses significantly affects its performance in cold weather. Rinnai uses R134a refrigerant, while Stiebel Eltron uses R134a. Both units use the same refrigerant type, so cold-weather performance should be comparable. R134a performs well across most of New Zealand but loses some efficiency in the coldest inland areas, so check the low-temperature rating if you are in Central Otago, Southland or inland Canterbury.
Pros and Cons
Rinnai
Pros
- Large NZ installer network and local support
- HydraHeat 340L suits big households
- Competitive installed bundles
- 7-year cylinder warranty
- Easy swap from an existing Rinnai system
Cons
- Integrated units are audible (45-46dB)
- Not as efficient as CO2 split systems
- Premium models approach split-system pricing
Stiebel Eltron
Pros
- German build quality, 100+ year heritage
- Direct NZ subsidiary and support
- Solid efficiency for an integrated unit
- Smart-element variants integrate with solar
- Proven in NZ conditions
Cons
- Heavier units
- Costs more than local mid-range brands
- Standard 5-year warranty
Which Should You Choose?
Choose Rinnai if...
- You want a lower upfront cost (from $6,500 vs $7,300)
- You want the best efficiency and lowest running costs (COP 4 vs 3.8)
- You want a longer tank warranty (7 years vs 5 years)
Choose Stiebel Eltron if...
- Quiet operation matters to you (44dB vs 45dB)
- You want lower annual running costs (~$250/yr vs ~$300/yr)
No rebates in NZ, whichever brand you pick
New Zealand has no STC-style scheme and no rebate for hot water heat pumps, so the installed price is the full price for both Rinnai and Stiebel Eltron. What can help: bank green home loan top-ups (about 1% p.a. fixed for 3 years at ANZ, ASB and BNZ; 0% up to $50,000 over 5 years at Westpac, if you have a home loan and equity). And if you currently have gas hot water, the NZ gas supply crunch is a reason to switch at end-of-life rather than buying another gas unit.
Where are you?
See indicative costs and local installers for your area