Every heated waterer 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. Waterers are grouped into heated poultry waterers, heated buckets and heated automatic waterers. Value and capacity use a separate scale for each group, because a 1.5 gallon automatic trough and a 1.5 gallon bucket do very different jobs. The other factors use one scale for all three.
| Factor | Measures | Weight |
|---|---|---|
| Value | price per gallon of capacity, against others of the same kind | 30% |
| Capacity | gallons held, against others of the same kind | 15% |
| Cold rating | lowest temperature the maker says the water stays ice-free at | 20% |
| Features | thermostat, protected cord, a cord of 6 ft or more, and insulation | 20% |
| Warranty | warranty length | 15% |
Where the numbers come from
Capacity, wattage, cold rating, cord length, features and warranty come from the maker’s product pages, manuals and brochures, or the maker’s own copy on a retail listing. Where a maker’s figures conflict, the maker’s own spec page or brochure is used over a retail listing. Prices are checked at Amazon and the maker’s own store, and the lowest price at a store the page links to is used.
The factors
Value is the current price divided by the capacity in gallons, on a log scale, so halving the price always counts the same. For poultry waterers, $40 per gallon scores zero and $12 full marks. For heated buckets, $30 per gallon scores zero and $6 full marks. For automatic waterers, $500 per gallon scores zero and $75 full marks.
Capacity is the water held. For poultry waterers, 2 gallons scores zero and 5 gallons full marks. For heated buckets, 2 gallons scores zero and 16 gallons full marks. For automatic waterers, 1.5 gallons scores zero and 20 gallons full marks.
Cold rating is the lowest air temperature at which the maker says the water stays ice-free: 20 °F scores zero and -20 °F full marks. A rating that refers only to the plastic not cracking, rather than the water staying liquid, is not counted.
Features is 30% for a thermostat that runs the heater only near freezing, 30% for a chew-protected cord, 20% for a cord of 6 ft or more and 20% for an insulated body or lid. A waterer that is wired in, with no cord, gets both cord shares.
Warranty is the maker’s warranty: none scores zero and 5 years full marks.
What isn’t scored
Wattage, weight, material, drinker type, the head count the maker gives and release date are listed but not scored. Wattage shows what a waterer costs to run, but more watts is neither better nor worse in itself, so it is shown rather than scored.
Missing data
If capacity isn’t published, value and capacity get the neutral middle score (50) and the product page marks them as estimated. Features score neutral only when none of them is published; a feature the maker doesn’t mention otherwise counts as absent. Two factors are exceptions. The cold rating is what most separates one heated waterer from another, so a maker that publishes no rating gets none counted: that factor scores zero and is marked estimated. Warranty works the same way, so a maker that doesn’t publish a warranty gets no warranty counted.
Ties and discontinued models
Products are ranked by score within each group. Discontinued models stay listed but rank below every current model and can be hidden with the “Hide discontinued” filter.