InstaShower Ultra
RV Tankless Water Heater with Mixing Tank
$729.99
$899.99
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More stable hot water from startup to shower.
InstaShower Ultra combines 66,000 BTU output, up to 3.9 GPM flow and a built-in mixing tank designed to reduce cold-water interruption. Segmented combustion targets steady outlet temperature.
View all features ↓66,000 BTUHigh-output propane water heating
Up to 3.9 GPMFlow for showers and daily use
±1°FTemperature stability target
0.5 GPMLow-flow burner activation
Best for high-demand travel, colder inlet water and customers prioritizing the strongest flow plus mixing-tank comfort.
Secure checkout
More options available at checkout
BACKED BY FOGATTI
Official WarrantyAutomatically activated with your direct order.2-year warranty · Original parts included
Reference valueReference value $60.00$0.00
Included
No forms · Latest-batch priority
Details
Original parts included
Your appliance, its original components and all original accessories included with your purchase are covered against defects in materials and workmanship.
2-year warranty
No separate registration required
Your direct order is your proof of purchase. Use your order number for warranty support—no registration form needed.
Priority for the latest available production
Direct orders receive priority for the newest available production batches for the selected model, color and fulfillment location. Product refinements may vary by batch; new features are not guaranteed.
Free contiguous U.S./Canada shipping30-day returns
Coverage period, exclusions, labor and shipping terms depend on your model. Review the full warranty terms before purchase.
View warranty terms (opens in a new tab)Specifications & support
Compare models
Choose your InstaShower
CURRENT MODEL
InstaShower Ultra
66K BTU · up to 3.9 GPM
Choose Ultra whenThe strongest flow and mixing-tank comfort are priorities under high demand.
InstaShower 9 Pro
66K BTU · up to 3.6 GPM
Choose 9 Pro whenA larger rig needs mixing-tank stability with slightly lower peak flow.
InstaShower 8 Plus
55K BTU · up to 2.9 GPM
Choose 8 Plus whenBalanced everyday family shower demand makes value and straightforward replacement more important.
What’s included
- ✓Water heaterInstaShower Ultra tankless unit
- ✓Access doorSelected color and door-size configuration
- ✓ControllerSmart wired controller
- ✓Safety valve150 PSI pressure relief valve
- ✓Product documentationInstallation hardware and user manual
Gas, water and electrical connection materials vary by RV.
Specifications
- Heat input
- 66,000 BTU
- Hot-water flow
- 0.5–3.9 GPM
- Temperature control
- ±1°F target
- Fuel
- LP propane
- Electrical supply
- 12V DC
- Maximum altitude
- 9,800 ft
Quick answers
How do I choose the door size?
Choose the option that matches your current door dimensions. Available sizes update with the selected
color.
What does the mixing tank do?
It buffers and blends water to reduce brief cold-water interruption when shower flow changes.
Does it need 120V power?
Controls and ignition use 12V DC; the burner uses LP propane. No 120V supply is required.
Complete your RV setup
Complete your RV setup
Pair the water-heater upgrade with climate equipment matched to the RV roof and duct layout.
For non-ducted travel trailers and fifth wheels
InstaCool Ultra
+$1,169.99
$1,749.99
Add quiet rooftop cooling and heat-pump warmth with a standard non-ducted roof opening and 115V supply.
Check roof fit and options
For larger ducted RVs and cold-weather travel
InstaHeat 35K
+$699.99
$1,299.99
Add stronger propane heat through a furnace matched to the RV cabinet and central duct system.
Check furnace fit and options![Fogatti Tankless Water Heater Door Gray [For InstaShower Ultra]](http://fogatti.com/cdn/shop/files/18_x18_door_1.jpg?v=1778818247&width=240)
Gray RV Heater Door
+$89.99
$189.99
Gray RV Heater Door Trim
+$49.99
15 × 18 Filling Block
+$24.99
$29.99
18 × 18 Filling Block
+$49.99
InstaShower Ultra
Checkout code
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$729.99
$899.99
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THE HIGHEST-FLOW INSTASHOWER
Smoother showers with maximum flow
InstaShower Ultra combines 66,000 BTU output, flow up to 3.9 GPM, a built-in mixing tank and a ±1°F temperature-control target. It is built for owners who want the strongest Fogatti tankless platform and fewer cold-water interruptions during normal RV shower use.
66,000 BTUHighest heat input
Up to 3.9 GPMHighest flow in the range
Built-in mixing tankSmoother restart
±1°FTemperature-control target
Reduce the frustrating parts of RV showers
Ultra is not only a larger burner. Its water path and staged combustion are designed around temperature stability during real use.
BUILT-IN MIXING TANK
Restart with less cold-water shock
The internal pre-mix system blends water before it leaves the heater, reducing the brief cold interruption that can happen in an RV plumbing loop.
SEGMENTED COMBUSTION
Adjust the flame as conditions change
Lower flame staging helps reduce overheating in warm conditions, while the full burner supports colder inlet water and higher demand.
HIGHER FLOW
Add flow margin for frequent showers
Ultra provides the strongest flow platform in the range, with delivered flow shaped by inlet-water temperature and temperature rise.
WEATHER-READY OPERATION
Travel higher and through colder routes
Correct propane, ventilation, 12V power and winterization remain essential for safe operation.
WHO SHOULD CHOOSE ULTRA?
Choose Ultra for maximum shower comfort
Ultra is designed for frequent users who value the mixing tank, higher output and steadier shower restarts.
A strong fit for frequent showers and higher demand
The 3.9 GPM platform adds more headroom for couples and families who use hot water often.
The mixing tank is the main comfort difference
It is designed to reduce cold-water interruption when the shower stops and restarts.
Choose 8 Pro or 8 Plus when the top output is unnecessary
The lower models can be a better value when household demand is lighter.
Door options for common RV water-heater openings
Choose 15×15, 15×18 or 18×18 from the actual wall opening and exterior trim coverage.
FIT AT A GLANCE
Door options for common RV water-heater openings.
Choose 15×15, 15×18 or 18×18 from the existing wall opening and exterior trim coverage; the installation guide covers utilities and venting.
- Minimum clear opening
- 13 × 13 in
- Door options
- 15×15 / 15×18 / 18×18 in
- Fuel
- LP propane
- Electrical supply
- 12V DC
- Maximum altitude
- 9,800 ft
White is offered in the configured 15 × 15-inch package; gray packages include the wider door options.
Compatible Accessories
In the Box
| Item | With Door | Without Door |
|---|---|---|
| Gas Water Heater × 1 | ✓ | ✓ |
| Installation and Operation Manual × 1 | ✓ | ✓ |
| Controller × 1 | ✓ | ✓ |
| Screw (ST5 × 25) × 12 | ✓ | ✓ |
| Screw (ST4 × 16) × 2 | ✓ | ✓ |
| Screw (M4 × 8) × 10 | — | ✓ |
| Screw (M4 × 6) × 4 | — | ✓ |
| Insulation Strip × 1 | ✓ | ✓ |
| Waterproof Sealing Strip (EPDM) × 1 | ✓ | ✓ |
Choose by flow, stability and fit
Choose Ultra for the 3.9 GPM platform and mixing tank, 8 Pro for 3.1 GPM control, or 8 Plus for everyday 2.9 GPM value.
InstaShower Ultra
For the highest flow, tighter control and reduced cold-water interruption.
- Heat input
- 66K BTU
- Flow
- Up to 3.9 GPM
- Comfort
- Built-in mixing tank
InstaShower 8 Pro
For regular shower use, up to 3.1 GPM and a ±1°F stability target.
- Heat input
- 62K BTU
- Flow
- Up to 3.1 GPM
- Best for
- Frequent use
InstaShower 8 Plus
For continuous hot water and everyday midsize-RV shower demand.
- Heat input
- 55K BTU
- Flow
- Up to 2.9 GPM
- Best for
- Everyday replacement
See Ultra performance and installation
Mixing-tank operation, full retrofit and owner performance in three practical videos.
▶
FULL REPLACEMENT
See a tankless replacement from removal to startup
A complete installation walkthrough covering the opening, connections and first hot water.
▶
TEARDOWN + TEST
See the mixing tank and burner before installation
An internal look at the parts designed to improve shower stability and service access.
▶
OWNER EXPERIENCE
See why the mixing tank matters in normal use
A practical review focused on cold-water interruption and shower consistency.
What owners say
FAQs
InstaShower Ultra FAQs
See how the mixing tank, high-flow platform and door choices support a confident upgrade.
Ready for smoother high-flow showers?
Choose the matching color and door package above. Review the installation guide before ordering.