Every salt chlorinator gets a score from 0 to 100% built from five factors, which maps onto the 5-point rating shown on the site (a 0% score would be 1.5 stars; a perfect score, 5). Each factor is scored against fixed reference points, not against the other products in the list, so adding a new model never moves another model’s rating. Systems are ranked within their pool type: above-ground systems, in-ground systems rated under 35,000 gallons, and in-ground systems rated for 35,000 gallons or more.
| Factor | Measures | Weight |
|---|---|---|
| Value | current price per pound of chlorine a day | 30% |
| Cell cost | replacement cell price per pound of chlorine a day | 20% |
| Warranty | cell and control center cover, on dealer-installed terms | 20% |
| Features | salt readout, Wi-Fi, automation links and safety cutoffs | 20% |
| Certification | NSF/ANSI 50 pool equipment standard | 10% |
Where the numbers come from
The chlorine output of each cell, in pounds of chlorine a day at its full setting, comes from the maker’s manual or spec sheet, or from the system’s NSF/ANSI 50 listing. Where a maker gives grams per hour, it’s converted (24 hours, 453.6 grams to the pound). Pool size ratings aren’t used for scoring: they’re the maker’s own claim and different brands rate the same output for quite different pools. Each product page links its sources.
The factors
Value is the current price of the complete system (control center and cell) per pound of chlorine a day, on a log scale: $3,000 per lb/day scores zero and $400 per lb/day full marks. Prices are checked and dated on each product page. Systems sold only through pool dealers and installers, with no published price, get the neutral middle score.
Cell cost is the price of the genuine replacement cell per pound of chlorine a day, on a log scale: $1,800 per lb/day scores zero and $300 per lb/day full marks. A cell lasts a few years, so over the life of a pool this is often the biggest cost.
Warranty is the years of full cover: the cell counts for 70% and the control center for 30%, with 1 year scoring zero and 5 years full marks. Prorated years don’t count. The terms scored are the maker’s best residential terms, which for Hayward, Pentair and Jandy means a system bought from an authorized dealer and professionally installed. Bought online and installed yourself, those makers often give less, and each product page lists the full terms.
Features adds up what makes a system easier to live with: a salt level readout (25%), built-in Wi-Fi with an app (25%, or 15% for an optional Wi-Fi module), control from a pool automation system (20%), automatic shutoff in cold water (10%), a flow switch or gas sensor that stops the cell when the water isn’t moving (10%), and a boost or super-chlorinate mode (10%).
Certification is whether the system is certified to NSF/ANSI 50, the standard for pool and spa equipment, which checks that the chlorine output claim holds up and the unit is safe in pool water. It scores full marks with a listing from NSF or another certifier, and zero without one.
What isn’t scored
Pool size rating. It’s shown, filterable and used to put systems in their pool type, but the chlorine output is what the score uses.
Cell life. Few makers publish it, and those that do quote hours under ideal conditions. Where it’s published, it’s listed on the product page.
Salt range, voltage and pipe size. These decide whether a system fits your pool and equipment pad, not how good it is. They’re listed on each product page.
Missing data
If a figure isn’t published, that factor gets the neutral middle score (50) and the product page marks it as estimated.
Ties and discontinued models
Products are ranked by score within each pool type. Discontinued models stay listed but rank below every current model and can be hidden with the “Hide discontinued” filter.