Every patio heater gets a score from 0 to 100% built from four 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. Heaters are grouped by fuel, gas and electric, and value and heat output have their own scale for each group.
| Factor | Measures | Weight |
|---|---|---|
| Value | price per 1,000 BTU/h of heat | 35% |
| Heat output | gas input in BTU/h, or electric power in W | 25% |
| Safety | tip-over shutoff, safety listing | 20% |
| Warranty | warranty length | 20% |
Where the numbers come from
BTU, wattage, safety features and warranty come from the maker’s product page, spec sheet or manual, or the maker’s own copy on its Amazon listing. Prices are checked at Amazon and the maker’s own store, and the lowest is used.
The factors
Value is the current price divided by the heat output in thousands of BTU per hour, on a log scale, so going from $8 to $4 counts as much as going from $4 to $2. An electric heater’s watts are converted at 3.412 BTU/h per watt. For gas heaters, $12 per 1,000 BTU/h scores zero and $2 full marks; for electric heaters, $80 scores zero and $10 full marks.
Heat output is the maker’s maximum gas input for gas heaters, where 10,000 BTU/h scores zero and 48,000 BTU/h full marks, and the rated power for electric heaters, where 1,000 W scores zero and 3,000 W full marks.
Safety counts two things: a tip-over shutoff that cuts the heat if the heater falls, and a listing from a testing lab (CSA, ETL or UL). Each is half the factor. A wall, ceiling or hanging heater can’t tip over, so it gets that half.
Warranty is the length of the warranty: 1 year scores zero and 3 years full marks.
What isn’t scored
The heated area the maker claims, style, ignition, remote, ingress rating and weight are listed but not scored. Heated area claims rest on assumptions that differ from maker to maker; heat output is compared instead.
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 group. Discontinued models stay listed but rank below every current model and can be hidden with the “Hide discontinued” filter.