A. O. Smith AOS-DFRO800 vs Aquasana HealthShield RO

Last updated: November 2, 2026

The A. O. Smith AOS-DFRO800 and the Aquasana HealthShield RO are evenly matched, rated 3.3 and 3.2. The A. O. Smith AOS-DFRO800 leads on price. The A. O. Smith AOS-DFRO800 costs $850 less ($449.99 vs $1,299.99).

A. O. Smith AOS-DFRO800 vs Aquasana HealthShield RO

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?

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 weightA. O. Smith AOS-DFRO800Aquasana HealthShield RO
Overall rating3.3/53.2/5
Certification 25%100 certified to NSF/ANSI 58100 certified to NSF/ANSI 58
Filter cost 20%0 $290 a year in replacement filters0 $350 a year in replacement filters
Water wasted 15%50 drain ratio not published (neutral score used)94 1.8:1 pure to drain
Output 10%71 800 gallons a day71 800 gallons a day
Price 15%54 $449.990 $1,299.99
Warranty 15%25 2-year warranty25 2-year warranty

Specifications

A. O. Smith AOS-DFRO800Aquasana HealthShield RO
Filtration
Output800 gallons a day800 gallons a day
Pure to drain-1.8:1
Stages22
RemineralizationNoNo
NSF/ANSI 58YesYes
Other certificationsNSF/ANSI 372NSF/ANSI 42, 53, 372, 401
Replacement filters$290 a year$350 a year
Build
TankTanklessTankless
Smart faucetNoNo
Warranty2 years2 years

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