Every garage heater gets a score from 0 to 100% built from three 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, electric and gas, and each group has its own value scale and controls list.
| Factor | Measures | Weight |
|---|---|---|
| Value | price per 1,000 BTU of heat output | 40% |
| Controls | thermostat, display, ignition and remote | 25% |
| Warranty | warranty on the heater | 35% |
Where the numbers come from
Heat output, power, efficiency, controls and warranty come from the maker’s product page, spec sheet or manual. Prices are checked at Amazon, the maker’s own store and heating retailers, 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 halving the price per 1,000 BTU always counts the same. For electric heaters $25 per 1,000 BTU scores zero and $4 full marks; for gas heaters $45 scores zero and $6 full marks. Gas heaters use the maker’s output rating, not the input. When a gas heater’s maker publishes only the input, output is modeled as input times the maker’s stated efficiency and marked estimated. When an electric heater’s maker gives only watts, output is worked out as watts x 3.412.
Controls are what come in the box. For electric heaters, a built-in thermostat counts for 50%, a digital display for 25% and a remote or app for 25%. For gas heaters, a thermostat in the box counts for 40%, electronic ignition (spark or hot surface, no standing pilot) for 40% and a remote or app for 20%. A thermostat sold separately doesn’t count, and a control the maker doesn’t mention counts as absent; the neutral score is used only when no controls are published.
Warranty is the maker’s warranty on the heater: 1 year scores zero and 5 years full marks. Longer cover on a gas heater’s heat exchanger is listed but not scored.
What isn’t scored
Power in watts, voltage, the gas types a heater takes, efficiency, venting type, rated garage size, weight and release date are listed but not scored.
Missing data
If a figure isn’t published, that factor gets the neutral middle score (50) and the product page marks it as estimated. The exception is warranty: a maker that doesn’t publish one gets no warranty counted, so that factor scores zero, the same as the shortest warranty on the scale, and is marked 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.