Rheem vs Rinnai: Which Hot Water Heat Pump Is Better? (2026)
Quick Verdict
Rheem is more budget-friendly with a lower upfront cost starting from $6,400, while Rinnai offers better protection with a 7-year tank warranty.
Side-by-Side Comparison
| Feature | Rheem | Rinnai |
|---|---|---|
| Price range (installed) | $6,400 - $11,000Lower | $6,500 - $9,500 |
| COP (efficiency) | 4 | 4 |
| Tank warranty | 5 years | 7 yearsLonger |
| Compressor warranty | 5 years | 5 years |
| Noise level | 42dBQuieter | 45dB |
| Annual running cost | ~$300/yr | ~$300/yr |
| Refrigerant type | R134a | R134a |
| Country | New Zealand / Australia | Japan / New Zealand |
| New Zealand brand | Yes | No |
| Best for | Homeowners who want a trusted name, the biggest installer network, and the most affordable entry price | Households wanting a well-supported mid-range option, especially larger families needing 275-340L capacity |
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 Rinnai starts from $6,500. That is a difference of roughly $100 at the entry level. Rheem is the more budget-friendly option upfront, though Rinnai 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 Rinnai reaches 4. Both systems offer identical efficiency, so running costs will be very similar.
Warranty Comparison
Rheem offers a 5-year tank warranty and 5-year compressor warranty. Rinnai offers a 7-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 Rheem. 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. Rheem operates at 42dB, while Rinnai runs at 45dB. 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 Rinnai 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
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
Which Should You Choose?
Choose Rheem if...
- You want a lower upfront cost (from $6,400 vs $6,500)
- Quiet operation matters to you (42dB vs 45dB)
- You want to buy from a New Zealand brand with local support
Choose Rinnai if...
- You want a longer tank warranty (7 years vs 5 years)
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 Rinnai. 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