Dometic DFSD20121
For a van, truck camper or small trailer that needs a low-draw doorless furnace.
Amazon $1,092.49$1,092.49
The Dometic DFSD20121 is the better RV furnace overall, rated 2.0 to 1.8. The Dometic DFSD20121 leads on power draw. The Suburban SF-20FQ (2551A) wins on value. The Suburban SF-20FQ (2551A) costs $141.31 less ($951.18 vs $1,092.49).
Prices were last checked November 9, 2026. Product prices and availability are accurate as of that date and are subject to change; the price and availability shown on Amazon or the retailer's site at the time of purchase apply. As an Amazon Associate we earn from qualifying purchases.
Suburban SF-20FQ (2551A)
A like-for-like replacement for an older 20,000 BTU Suburban SF furnace in a small trailer.
Amazon $951.18$951.18
Which should you buy?
- Choose the Dometic DFSD20121 for power draw (4.8 A running, 0.3 A per 1,000 BTU vs 7 A running, 0.3 A per 1,000 BTU).
- Choose the Suburban SF-20FQ (2551A) for value ($47.56 per 1,000 BTU ($951.18, 20,000 BTU) vs $60.69 per 1,000 BTU ($1,092.49, 18,000 BTU)).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every under 25,000 BTU RV furnace; a clear win is highlighted. How we rank explains each one.
| Factor weight | Dometic DFSD20121 | Suburban SF-20FQ (2551A) |
|---|---|---|
| Overall rating | 2.0/5 | 1.8/5 |
| Value 40% | 5 $60.69 per 1,000 BTU ($1,092.49, 18,000 BTU) | 24 $47.56 per 1,000 BTU ($951.18, 20,000 BTU) |
| Power draw 35% | 36 4.8 A running, 0.3 A per 1,000 BTU | 0 7 A running, 0.3 A per 1,000 BTU |
| Warranty 25% | 0 warranty not published, scored as none | 0 warranty not published, scored as none |
Specifications
| Dometic DFSD20121 | Suburban SF-20FQ (2551A) | |
|---|---|---|
| Heat and power | ||
| Input capacity | 18,000 BTU | 20,000 BTU |
| 12 V amp draw | 4.8 A | 7 A |
| Airflow | - | 300 CFM |
| Discharge | Ducted | Ducted |
| Fit | ||
| Height | 7 in | 7.5 in |
| Weight | 20.8 lb | 29 lb |