iStore vs Stiebel Eltron: Which Heat Pump Is Better? (2026)
Quick Verdict
Stiebel Eltron is the more efficient choice with a higher COP rating, meaning lower running costs over time, while iStore is more budget-friendly with a lower upfront cost starting from $2,800.
Side-by-Side Comparison
| Feature | iStore | Stiebel Eltron |
|---|---|---|
| Price range (installed) | $2,800 - $4,200Lower | $3,500 - $5,000 |
| COP (efficiency) | 3.2 | 3.8Higher |
| Tank warranty | 5 years | 5 years |
| Compressor warranty | 5 years | 5 years |
| Noise level | 49dB | 44dBQuieter |
| Annual running cost | ~$340/yr | ~$340/yr |
| Refrigerant type | R134a | R134a |
| Country of manufacture | Australia | Germany |
| Australian made | Yes | No |
| Best for | Budget-conscious households wanting maximum rebate impact and simple installation | Those who value German engineering and build quality at a mid-to-premium price point |
Price Comparison
iStore starts from $2,800 installed (before rebates), while Stiebel Eltron starts from $3,500. That is a difference of roughly $700 at the entry level. iStore is the more budget-friendly option upfront, though Stiebel Eltron 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. iStore achieves a COP of 3.2, while Stiebel Eltron reaches 3.8. The Stiebel Eltron is 19% more efficient, which translates to roughly $0 less per year in running costs. Over a 10-year lifespan, that efficiency advantage adds up to approximately $0 in savings.
Warranty Comparison
iStore 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. iStore operates at 49dB, 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. iStore 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 in moderate climates but may lose some efficiency in very cold conditions.
Pros and Cons
iStore
Pros
- Most affordable option
- Australian company
- Simple installation
- Good rebate value (low cost means rebates cover more)
- Widely available
Cons
- Lower COP than premium brands
- Shorter warranty
- Noisier than split systems
- Higher running costs long-term
Stiebel Eltron
Pros
- German engineering quality
- Good efficiency
- Solid warranty backing
- Established global brand (100+ years)
- Strong Australian support network
Cons
- Higher cost than local brands
- Heavier unit
- Not Australian-made (misses higher VIC rebate tier)
Which Should You Choose?
Choose iStore if...
- You want a lower upfront cost (from $2,800 vs $3,500)
- You want Australian-made (eligible for higher VIC rebate tier of $1,400 vs $1,000)
Choose Stiebel Eltron if...
- You want the best efficiency and lowest running costs (COP 3.8 vs 3.2)
- Quiet operation matters to you (44dB vs 49dB)