Aquasana HealthShield RO
#9 in TanklessFull review
For a buyer who wants the broadest certification in a fast tankless system and doesn’t mind the price. Most households get similar output for much less elsewhere.
Amazon $1,299.99$1,299.99
The Aquasana HealthShield RO is the better under-sink reverse osmosis system overall, rated 3.2 to 3.0. The Aquasana HealthShield RO leads on certification and warranty. The iSpring RO800G wins on filter cost and price. The iSpring RO800G costs $841 less ($458.99 vs $1,299.99).
iSpring RO800G
#14 in TanklessFull review
For big households that want fast tankless RO with low waste and cheap filters. It lacks the third-party certification of pricier rivals.
Amazon $458.99$458.99
Prices were last checked November 2, 2026 and are subject to change; the price and availability shown by the retailer at the time of purchase apply.
Which should you buy?
- Choose the Aquasana HealthShield RO for certification (certified to NSF/ANSI 58 vs no third-party certification) and warranty (2-year warranty vs 1-year warranty).
- Choose the iSpring RO800G for filter cost ($85 a year in replacement filters vs $350 a year in replacement filters) and price ($458.99 vs $1,299.99).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every tankless under-sink reverse osmosis system; a clear win is highlighted. How we rank explains each one.
| Factor weight | Aquasana HealthShield RO | iSpring RO800G |
|---|---|---|
| Overall rating | 3.2/5 | 3.0/5 |
| Certification 25% | 100 certified to NSF/ANSI 58 | 0 no third-party certification |
| Filter cost 20% | 0 $350 a year in replacement filters | 67 $85 a year in replacement filters |
| Water wasted 15% | 94 1.8:1 pure to drain | 98 2.5:1 pure to drain |
| Output 10% | 71 800 gallons a day | 71 800 gallons a day |
| Price 15% | 0 $1,299.99 | 53 $458.99 |
| Warranty 15% | 25 2-year warranty | 0 1-year warranty |
Specifications
| Aquasana HealthShield RO | iSpring RO800G | |
|---|---|---|
| Filtration | ||
| Output | 800 gallons a day | 800 gallons a day |
| Pure to drain | 1.8:1 | 2.5:1 |
| Stages | 2 | 2 |
| Remineralization | No | No |
| NSF/ANSI 58 | Yes | No |
| Other certifications | NSF/ANSI 42, 53, 372, 401 | - |
| Replacement filters | $350 a year | $85 a year |
| Build | ||
| Tank | Tankless | Tankless |
| Booster pump | - | Yes |
| Smart faucet | No | No |
| Warranty | 2 years | 1 year |