Rheem vs Stiebel Eltron: Which Hot Water Heat Pump Is Better? (2026)
Quick Verdict
Rheem is the more efficient choice with a higher COP rating, meaning lower running costs over time.
Side-by-Side Comparison
| Feature | Rheem | Stiebel Eltron |
|---|---|---|
| Price range (installed) | $6,400 - $11,000Lower | $7,300 - $9,500 |
| COP (efficiency) | 4Higher | 3.8 |
| Tank warranty | 5 years | 5 years |
| Compressor warranty | 5 years | 5 years |
| Noise level | 42dBQuieter | 44dB |
| Annual running cost | ~$300/yr | ~$250/yrLower |
| Refrigerant type | R134a | R134a |
| Country | New Zealand / Australia | Germany |
| New Zealand brand | Yes | No |
| Best for | Homeowners who want a trusted name, the biggest installer network, and the most affordable entry price | 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
Rheem starts from $6,400 installed (indicative, June 2026), while Stiebel Eltron starts from $7,300. That is a difference of roughly $900 at the entry level. Rheem 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. Rheem achieves a COP of 4, while Stiebel Eltron reaches 3.8. The Rheem 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
Rheem offers a 5-year tank warranty and 5-year compressor warranty. Stiebel Eltron offers a 5-year tank warranty and 5-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. Rheem operates at 42dB, while Stiebel Eltron runs at 44dB. The Rheem is quieter at 42dB. 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. Rheem 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
Rheem
Pros
- Trusted household name in NZ
- Widest installer and service network
- Entry bundles from about $6,400 installed
- Integrated models are simple replacements for an electric cylinder
- Local support and parts availability
Cons
- Integrated models are noisier than split systems
- Standard warranty shorter than premium brands
- Lower COP than CO2 split systems
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 Rheem if...
- You want a lower upfront cost (from $6,400 vs $7,300)
- You want the best efficiency and lowest running costs (COP 4 vs 3.8)
- Quiet operation matters to you (42dB vs 44dB)
- You want to buy from a New Zealand brand with local support
Choose Stiebel Eltron if...
- 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 Rheem 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