A 6-gallon steel tank heater on propane for a straight swap in an RV with the matching cutout.
Amazon $399.99The KingRVer 6 Gallon Propane DSI rates 2.8 among tank RV water heaters; the Suburban ST-42 (5481A) rates 2.6 among tankless ones. The KingRVer 6 Gallon Propane DSI costs $5 less ($399.99 vs $404.99).
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.

A tankless heater rated 42,000 BTU for endless hot water in an RV that has the cutout for it.
Amazon $404.99Scores side by side
These two sit in different type classes (tank and tankless), and each is scored against the reference points for its own class, so a rating says how well each does among its own type peers. How we rank explains each factor.
| Factor weight | KingRVer 6 Gallon Propane DSI | Suburban ST-42 (5481A) |
|---|---|---|
| Overall rating | 2.8/5 | 2.6/5 |
| Value 40% | 50 $66.67 per gallon of tank ($399.99, 6 gal) | 35 $9.64 per 1,000 BTU ($404.99, 42,000 BTU) |
| Hot water output 35% | 50 recovery rate not published (neutral score used) | 50 maximum flow not published (neutral score used) |
| Warranty 25% | 0 warranty not published, scored as none | 0 warranty not published, scored as none |
Specifications
| KingRVer 6 Gallon Propane DSI | Suburban ST-42 (5481A) | |
|---|---|---|
| Heat and water | ||
| Input capacity | - | 42,000 BTU |
| Tank size | 6 gal | - |
| Fuel | Propane | Propane |
| Fit | ||
| Weight | 36.2 lb | 21 lb |