Suburban SF-42VHFQ
For a 40,000 BTU furnace in an RV with no exterior door and a long duct run.
Amazon $1,185.98$1,185.98
The Suburban SF-42VHFQ is the better RV furnace overall, rated 3.4 to 3.0. The Dometic DFLD40121 costs $30.44 less ($1,155.54 vs $1,185.98).
Prices were last checked November 4, 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.
Dometic DFLD40121
For a large motorhome or fifth wheel with a doorless Dometic furnace to replace.
Amazon $1,155.54$1,155.54
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every 35,000 BTU and up RV furnace; a clear win is highlighted. How we rank explains each one.
| Factor weight | Suburban SF-42VHFQ | Dometic DFLD40121 |
|---|---|---|
| Overall rating | 3.4/5 | 3.0/5 |
| Value 40% | 61 $29.65 per 1,000 BTU ($1,185.98, 40,000 BTU) | 63 $28.89 per 1,000 BTU ($1,155.54, 40,000 BTU) |
| Power draw 35% | 50 12 V amp draw not published (neutral score used) | 50 12 V amp draw not published (neutral score used) |
| Warranty 25% | 50 2-year warranty | 0 warranty not published, scored as none |
Specifications
| Suburban SF-42VHFQ | Dometic DFLD40121 | |
|---|---|---|
| Heat and power | ||
| Input capacity | 40,000 BTU | 40,000 BTU |
| Discharge | Ducted | Ducted |
| Fit | ||
| Height | 7.5 in | - |
| Weight | 28 lb | 35.5 lb |
| Warranty | ||
| Warranty | 2 years | - |