Every RV furnace 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. Furnaces are grouped by rated input (under 25,000 BTU, 25,000 to 30,000, and 35,000 and up).
| Factor | Measures | Weight |
|---|---|---|
| Value | price per 1,000 BTU of input | 40% |
| Power draw | 12 V amps per 1,000 BTU, which is battery drain on a dry camp | 35% |
| Warranty | warranty on the furnace | 25% |
Where the numbers come from
BTU rating, amp draw, airflow, weight and warranty come from the maker’s spec sheet, manual or product page where one is published, and otherwise from the Amazon listing. Suburban’s service and user manuals, and Dometic’s product pages, are the main maker sources. Many sellers publish only a BTU figure, and the product page says where a number comes from. Prices are Amazon prices; the product page notes a price from a sale offer.
The factors
Value is the current price divided by the rated input in BTU, per 1,000 BTU, on a log scale, so going from $60 to $30 per 1,000 BTU counts as much as going from $30 to $15. $65 scores zero and $18 full marks.
Power draw is the 12 V current while the furnace runs, divided by its rating: amps per 1,000 BTU, where lower means less battery drain on a dry camp. 0.35 A per 1,000 BTU scores zero and 0.12 A full marks.
Warranty is the limited warranty on the furnace: 1 year scores zero and 3 years full marks.
What isn’t scored
Airflow, ducted or direct discharge, height and weight are listed but not scored. Airflow figures aren’t measured the same way by every maker, and a higher number isn’t better for every duct layout. Noise isn’t scored because only a few makers publish a rating, and the ones that do (such as a “40 dB sleep mode” claim) don’t say how it’s measured.
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 seller 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.
What isn’t ranked
Replacement cores sold without the housing, blower or controls, parts, 120 V AC park-model furnaces, wall and portable heaters, and diesel air heaters aren’t ranked.
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.