Fogatti InstaShower Ultra (FS10B1SGD)
#10 in TanklessFull review
A tankless heater rated 66,000 BTU for endless hot water in an RV that has the cutout for it.
Amazon $799.99$799.99
The Fogatti InstaShower Ultra (FS10B1SGD) is the better RV water heater overall, rated 3.0 to 2.2. The Fogatti InstaShower Ultra (FS10B1SGD) leads on value. The Girard 2GWHAM 42,000 BTU costs $165.38 less ($634.61 vs $799.99).
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.
Girard 2GWHAM 42,000 BTU
#18 in TanklessFull review
A tankless heater rated 42,000 BTU for endless hot water in an RV that has the cutout for it.
Amazon $634.61$634.61
Which should you buy?
- Choose the Fogatti InstaShower Ultra (FS10B1SGD) for value ($12.12 per 1,000 BTU ($799.99, 66,000 BTU) vs $15.11 per 1,000 BTU ($634.61, 42,000 BTU)).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every tankless RV water heater; a clear win is highlighted. How we rank explains each one.
| Factor weight | Fogatti InstaShower Ultra (FS10B1SGD) | Girard 2GWHAM 42,000 BTU |
|---|---|---|
| Overall rating | 3.0/5 | 2.2/5 |
| Value 40% | 22 $12.12 per 1,000 BTU ($799.99, 66,000 BTU) | 10 $15.11 per 1,000 BTU ($634.61, 42,000 BTU) |
| Hot water output 35% | 100 up to 3.9 GPM | 50 maximum flow not published (neutral score used) |
| Warranty 25% | 0 warranty not published, scored as none | 0 1-year warranty |
Specifications
| Fogatti InstaShower Ultra (FS10B1SGD) | Girard 2GWHAM 42,000 BTU | |
|---|---|---|
| Heat and water | ||
| Input capacity | 66,000 BTU | 42,000 BTU |
| Maximum flow | 3.9 GPM | - |
| Fuel | Propane | Propane |
| 12 V amp draw | - | 3 A |
| Fit | ||
| Weight | - | 23 lb |
| Warranty | ||
| Warranty | - | 1 year |